[ios, macos] Add support for data-driven property functions

include/mbgl/style/data_driven_property_value.hpp

@@ -26,6 +26,11 @@ private:
         return lhs.value == rhs.value;
     }
 
+    friend bool operator!=(const DataDrivenPropertyValue& lhs,
+                           const DataDrivenPropertyValue& rhs) {
+        return !(lhs == rhs);
+    }
+
 public:
     DataDrivenPropertyValue() = default;
     DataDrivenPropertyValue(                  T  v) : value(std::move(v)) {}

platform/darwin/src/MGLBackgroundStyleLayer.h

@@ -13,11 +13,11 @@ NS_ASSUME_NONNULL_BEGIN
  map content. If the style’s other layers use the Mapbox Streets source, the
  background style layer is responsible for drawing land, whereas the oceans and
  other bodies of water are drawn by `MGLFillStyleLayer` objects.
-
+ 
  A background style layer is typically the bottommost layer in a style, because
  it covers the entire map and can occlude any layers below it. You can therefore
  access it by getting the last item in the `MGLStyle.layers` array.
-
+ 
  If the background style layer is transparent or omitted from the style, any
  portion of the map view that does not show another style layer is transparent.
  */
@@ -31,11 +31,11 @@ MGL_EXPORT
 #if TARGET_OS_IPHONE
 /**
  The color with which the background will be drawn.
-
+ 
  The default value of this property is an `MGLStyleValue` object containing
  `UIColor.blackColor`. Set this property to `nil` to reset it to the default
  value.
-
+ 
  This property is only applied to the style if `backgroundPattern` is set to
  `nil`. Otherwise, it is ignored.
  */
@@ -43,11 +43,11 @@ MGL_EXPORT
 #else
 /**
  The color with which the background will be drawn.
-
+ 
  The default value of this property is an `MGLStyleValue` object containing
  `NSColor.blackColor`. Set this property to `nil` to reset it to the default
  value.
-
+ 
  This property is only applied to the style if `backgroundPattern` is set to
  `nil`. Otherwise, it is ignored.
  */
@@ -56,7 +56,7 @@ MGL_EXPORT
 
 /**
  The opacity at which the background will be drawn.
-
+ 
  The default value of this property is an `MGLStyleValue` object containing an
  `NSNumber` object containing the float `1`. Set this property to `nil` to reset
  it to the default value.

platform/darwin/src/MGLBackgroundStyleLayer.mm

@@ -86,28 +86,34 @@
 - (void)setBackgroundColor:(MGLStyleValue<MGLColor *> *)backgroundColor {
     MGLAssertStyleLayerIsValid();
 
-    auto mbglValue = MGLStyleValueTransformer<mbgl::Color, MGLColor *>().toPropertyValue(backgroundColor);
+    auto mbglValue = MGLStyleValueTransformer<mbgl::Color, MGLColor *>().toInterpolatablePropertyValue(backgroundColor);
     self.rawLayer->setBackgroundColor(mbglValue);
 }
 
 - (MGLStyleValue<MGLColor *> *)backgroundColor {
     MGLAssertStyleLayerIsValid();
 
-    auto propertyValue = self.rawLayer->getBackgroundColor() ?: self.rawLayer->getDefaultBackgroundColor();
+    auto propertyValue = self.rawLayer->getBackgroundColor();
+    if (propertyValue.isUndefined()) {
+        return MGLStyleValueTransformer<mbgl::Color, MGLColor *>().toStyleValue(self.rawLayer->getDefaultBackgroundColor());
+    }
     return MGLStyleValueTransformer<mbgl::Color, MGLColor *>().toStyleValue(propertyValue);
 }
 
 - (void)setBackgroundOpacity:(MGLStyleValue<NSNumber *> *)backgroundOpacity {
     MGLAssertStyleLayerIsValid();
 
-    auto mbglValue = MGLStyleValueTransformer<float, NSNumber *>().toPropertyValue(backgroundOpacity);
+    auto mbglValue = MGLStyleValueTransformer<float, NSNumber *>().toInterpolatablePropertyValue(backgroundOpacity);
     self.rawLayer->setBackgroundOpacity(mbglValue);
 }
 
 - (MGLStyleValue<NSNumber *> *)backgroundOpacity {
     MGLAssertStyleLayerIsValid();
 
-    auto propertyValue = self.rawLayer->getBackgroundOpacity() ?: self.rawLayer->getDefaultBackgroundOpacity();
+    auto propertyValue = self.rawLayer->getBackgroundOpacity();
+    if (propertyValue.isUndefined()) {
+        return MGLStyleValueTransformer<float, NSNumber *>().toStyleValue(self.rawLayer->getDefaultBackgroundOpacity());
+    }
     return MGLStyleValueTransformer<float, NSNumber *>().toStyleValue(propertyValue);
 }
 
@@ -121,7 +127,10 @@
 - (MGLStyleValue<NSString *> *)backgroundPattern {
     MGLAssertStyleLayerIsValid();
 
-    auto propertyValue = self.rawLayer->getBackgroundPattern() ?: self.rawLayer->getDefaultBackgroundPattern();
+    auto propertyValue = self.rawLayer->getBackgroundPattern();
+    if (propertyValue.isUndefined()) {
+        return MGLStyleValueTransformer<std::string, NSString *>().toStyleValue(self.rawLayer->getDefaultBackgroundPattern());
+    }
     return MGLStyleValueTransformer<std::string, NSString *>().toStyleValue(propertyValue);
 }
 

platform/darwin/src/MGLCircleStyleLayer.h

@@ -44,12 +44,12 @@ typedef NS_ENUM(NSUInteger, MGLCircleTranslationAnchor) {
 /**
  An `MGLCircleStyleLayer` is a style layer that renders one or more filled
  circles on the map.
-
+ 
  Use a circle style layer to configure the visual appearance of point or point
  collection features in vector tiles loaded by an `MGLVectorSource` object or
  `MGLPointAnnotation`, `MGLPointFeature`, `MGLPointCollection`, or
  `MGLPointCollectionFeature` instances in an `MGLShapeSource` object.
-
+ 
  A circle style layer renders circles whose radii are measured in screen units.
  To display circles on the map whose radii correspond to real-world distances,
  use many-sided regular polygons and configure their appearance using an
@@ -84,7 +84,7 @@ MGL_EXPORT
 /**
  Amount to blur the circle. 1 blurs the circle such that only the centerpoint is
  full opacity.
-
+ 
  The default value of this property is an `MGLStyleValue` object containing an
  `NSNumber` object containing the float `0`. Set this property to `nil` to reset
  it to the default value.
@@ -94,7 +94,7 @@ MGL_EXPORT
 #if TARGET_OS_IPHONE
 /**
  The fill color of the circle.
-
+ 
  The default value of this property is an `MGLStyleValue` object containing
  `UIColor.blackColor`. Set this property to `nil` to reset it to the default
  value.
@@ -103,7 +103,7 @@ MGL_EXPORT
 #else
 /**
  The fill color of the circle.
-
+ 
  The default value of this property is an `MGLStyleValue` object containing
  `NSColor.blackColor`. Set this property to `nil` to reset it to the default
  value.
@@ -113,7 +113,7 @@ MGL_EXPORT
 
 /**
  The opacity at which the circle will be drawn.
-
+ 
  The default value of this property is an `MGLStyleValue` object containing an
  `NSNumber` object containing the float `1`. Set this property to `nil` to reset
  it to the default value.
@@ -122,9 +122,9 @@ MGL_EXPORT
 
 /**
  Circle radius.
-
+ 
  This property is measured in points.
-
+ 
  The default value of this property is an `MGLStyleValue` object containing an
  `NSNumber` object containing the float `5`. Set this property to `nil` to reset
  it to the default value.
@@ -133,11 +133,11 @@ MGL_EXPORT
 
 /**
  Controls the scaling behavior of the circle when the map is pitched.
-
+ 
  The default value of this property is an `MGLStyleValue` object containing an
  `NSValue` object containing `MGLCircleScaleAlignmentMap`. Set this property to
  `nil` to reset it to the default value.
-
+ 
  This attribute corresponds to the <a
  href="https://www.mapbox.com/mapbox-gl-style-spec/#paint-circle-pitch-scale"><code>circle-pitch-scale</code></a>
  layout property in the Mapbox Style Specification.
@@ -149,7 +149,7 @@ MGL_EXPORT
 #if TARGET_OS_IPHONE
 /**
  The stroke color of the circle.
-
+ 
  The default value of this property is an `MGLStyleValue` object containing
  `UIColor.blackColor`. Set this property to `nil` to reset it to the default
  value.
@@ -158,7 +158,7 @@ MGL_EXPORT
 #else
 /**
  The stroke color of the circle.
-
+ 
  The default value of this property is an `MGLStyleValue` object containing
  `NSColor.blackColor`. Set this property to `nil` to reset it to the default
  value.
@@ -168,7 +168,7 @@ MGL_EXPORT
 
 /**
  The opacity of the circle's stroke.
-
+ 
  The default value of this property is an `MGLStyleValue` object containing an
  `NSNumber` object containing the float `1`. Set this property to `nil` to reset
  it to the default value.
@@ -177,10 +177,10 @@ MGL_EXPORT
 
 /**
  The width of the circle's stroke. Strokes are placed outside of the
- "circle-radius".
-
+ `circleRadius`.
+ 
  This property is measured in points.
-
+ 
  The default value of this property is an `MGLStyleValue` object containing an
  `NSNumber` object containing the float `0`. Set this property to `nil` to reset
  it to the default value.
@@ -190,13 +190,13 @@ MGL_EXPORT
 #if TARGET_OS_IPHONE
 /**
  The geometry's offset.
-
+ 
  This property is measured in points.
-
+ 
  The default value of this property is an `MGLStyleValue` object containing an
  `NSValue` object containing a `CGVector` struct set to 0 points rightward and 0
  points downward. Set this property to `nil` to reset it to the default value.
-
+ 
  This attribute corresponds to the <a
  href="https://www.mapbox.com/mapbox-gl-style-spec/#paint-circle-translate"><code>circle-translate</code></a>
  layout property in the Mapbox Style Specification.
@@ -205,13 +205,13 @@ MGL_EXPORT
 #else
 /**
  The geometry's offset.
-
+ 
  This property is measured in points.
-
+ 
  The default value of this property is an `MGLStyleValue` object containing an
  `NSValue` object containing a `CGVector` struct set to 0 points rightward and 0
  points upward. Set this property to `nil` to reset it to the default value.
-
+ 
  This attribute corresponds to the <a
  href="https://www.mapbox.com/mapbox-gl-style-spec/#paint-circle-translate"><code>circle-translate</code></a>
  layout property in the Mapbox Style Specification.
@@ -223,14 +223,14 @@ MGL_EXPORT
 
 /**
  Controls the translation reference point.
-
+ 
  The default value of this property is an `MGLStyleValue` object containing an
  `NSValue` object containing `MGLCircleTranslationAnchorMap`. Set this property
  to `nil` to reset it to the default value.
-
+ 
  This property is only applied to the style if `circleTranslation` is non-`nil`.
  Otherwise, it is ignored.
-
+ 
  This attribute corresponds to the <a
  href="https://www.mapbox.com/mapbox-gl-style-spec/#paint-circle-translate-anchor"><code>circle-translate-anchor</code></a>
  layout property in the Mapbox Style Specification.

platform/darwin/src/MGLCircleStyleLayer.mm

@@ -136,57 +136,69 @@ namespace mbgl {
 - (void)setCircleBlur:(MGLStyleValue<NSNumber *> *)circleBlur {
     MGLAssertStyleLayerIsValid();
 
-    auto mbglValue = MGLStyleValueTransformer<float, NSNumber *>().toPropertyValue(circleBlur);
+    auto mbglValue = MGLStyleValueTransformer<float, NSNumber *>().toDataDrivenPropertyValue(circleBlur);
     self.rawLayer->setCircleBlur(mbglValue);
 }
 
 - (MGLStyleValue<NSNumber *> *)circleBlur {
     MGLAssertStyleLayerIsValid();
 
-    auto propertyValue = self.rawLayer->getCircleBlur() ?: self.rawLayer->getDefaultCircleBlur();
-    return MGLStyleValueTransformer<float, NSNumber *>().toStyleValue(propertyValue);
+    auto propertyValue = self.rawLayer->getCircleBlur();
+    if (propertyValue.isUndefined()) {
+        return MGLStyleValueTransformer<float, NSNumber *>().toDataDrivenStyleValue(self.rawLayer->getDefaultCircleBlur());
+    }
+    return MGLStyleValueTransformer<float, NSNumber *>().toDataDrivenStyleValue(propertyValue);
 }
 
 - (void)setCircleColor:(MGLStyleValue<MGLColor *> *)circleColor {
     MGLAssertStyleLayerIsValid();
 
-    auto mbglValue = MGLStyleValueTransformer<mbgl::Color, MGLColor *>().toPropertyValue(circleColor);
+    auto mbglValue = MGLStyleValueTransformer<mbgl::Color, MGLColor *>().toDataDrivenPropertyValue(circleColor);
     self.rawLayer->setCircleColor(mbglValue);
 }
 
 - (MGLStyleValue<MGLColor *> *)circleColor {
     MGLAssertStyleLayerIsValid();
 
-    auto propertyValue = self.rawLayer->getCircleColor() ?: self.rawLayer->getDefaultCircleColor();
-    return MGLStyleValueTransformer<mbgl::Color, MGLColor *>().toStyleValue(propertyValue);
+    auto propertyValue = self.rawLayer->getCircleColor();
+    if (propertyValue.isUndefined()) {
+        return MGLStyleValueTransformer<mbgl::Color, MGLColor *>().toDataDrivenStyleValue(self.rawLayer->getDefaultCircleColor());
+    }
+    return MGLStyleValueTransformer<mbgl::Color, MGLColor *>().toDataDrivenStyleValue(propertyValue);
 }
 
 - (void)setCircleOpacity:(MGLStyleValue<NSNumber *> *)circleOpacity {
     MGLAssertStyleLayerIsValid();
 
-    auto mbglValue = MGLStyleValueTransformer<float, NSNumber *>().toPropertyValue(circleOpacity);
+    auto mbglValue = MGLStyleValueTransformer<float, NSNumber *>().toDataDrivenPropertyValue(circleOpacity);
     self.rawLayer->setCircleOpacity(mbglValue);
 }
 
 - (MGLStyleValue<NSNumber *> *)circleOpacity {
     MGLAssertStyleLayerIsValid();
 
-    auto propertyValue = self.rawLayer->getCircleOpacity() ?: self.rawLayer->getDefaultCircleOpacity();
-    return MGLStyleValueTransformer<float, NSNumber *>().toStyleValue(propertyValue);
+    auto propertyValue = self.rawLayer->getCircleOpacity();
+    if (propertyValue.isUndefined()) {
+        return MGLStyleValueTransformer<float, NSNumber *>().toDataDrivenStyleValue(self.rawLayer->getDefaultCircleOpacity());
+    }
+    return MGLStyleValueTransformer<float, NSNumber *>().toDataDrivenStyleValue(propertyValue);
 }
 
 - (void)setCircleRadius:(MGLStyleValue<NSNumber *> *)circleRadius {
     MGLAssertStyleLayerIsValid();
 
-    auto mbglValue = MGLStyleValueTransformer<float, NSNumber *>().toPropertyValue(circleRadius);
+    auto mbglValue = MGLStyleValueTransformer<float, NSNumber *>().toDataDrivenPropertyValue(circleRadius);
     self.rawLayer->setCircleRadius(mbglValue);
 }
 
 - (MGLStyleValue<NSNumber *> *)circleRadius {
     MGLAssertStyleLayerIsValid();
 
-    auto propertyValue = self.rawLayer->getCircleRadius() ?: self.rawLayer->getDefaultCircleRadius();
-    return MGLStyleValueTransformer<float, NSNumber *>().toStyleValue(propertyValue);
+    auto propertyValue = self.rawLayer->getCircleRadius();
+    if (propertyValue.isUndefined()) {
+        return MGLStyleValueTransformer<float, NSNumber *>().toDataDrivenStyleValue(self.rawLayer->getDefaultCircleRadius());
+    }
+    return MGLStyleValueTransformer<float, NSNumber *>().toDataDrivenStyleValue(propertyValue);
 }
 
 - (void)setCircleScaleAlignment:(MGLStyleValue<NSValue *> *)circleScaleAlignment {
@@ -199,7 +211,10 @@ namespace mbgl {
 - (MGLStyleValue<NSValue *> *)circleScaleAlignment {
     MGLAssertStyleLayerIsValid();
 
-    auto propertyValue = self.rawLayer->getCirclePitchScale() ?: self.rawLayer->getDefaultCirclePitchScale();
+    auto propertyValue = self.rawLayer->getCirclePitchScale();
+    if (propertyValue.isUndefined()) {
+        return MGLStyleValueTransformer<mbgl::style::CirclePitchScaleType, NSValue *, mbgl::style::CirclePitchScaleType, MGLCircleScaleAlignment>().toEnumStyleValue(self.rawLayer->getDefaultCirclePitchScale());
+    }
     return MGLStyleValueTransformer<mbgl::style::CirclePitchScaleType, NSValue *, mbgl::style::CirclePitchScaleType, MGLCircleScaleAlignment>().toEnumStyleValue(propertyValue);
 }
 
@@ -213,56 +228,68 @@ namespace mbgl {
 - (void)setCircleStrokeColor:(MGLStyleValue<MGLColor *> *)circleStrokeColor {
     MGLAssertStyleLayerIsValid();
 
-    auto mbglValue = MGLStyleValueTransformer<mbgl::Color, MGLColor *>().toPropertyValue(circleStrokeColor);
+    auto mbglValue = MGLStyleValueTransformer<mbgl::Color, MGLColor *>().toDataDrivenPropertyValue(circleStrokeColor);
     self.rawLayer->setCircleStrokeColor(mbglValue);
 }
 
 - (MGLStyleValue<MGLColor *> *)circleStrokeColor {
     MGLAssertStyleLayerIsValid();
 
-    auto propertyValue = self.rawLayer->getCircleStrokeColor() ?: self.rawLayer->getDefaultCircleStrokeColor();
-    return MGLStyleValueTransformer<mbgl::Color, MGLColor *>().toStyleValue(propertyValue);
+    auto propertyValue = self.rawLayer->getCircleStrokeColor();
+    if (propertyValue.isUndefined()) {
+        return MGLStyleValueTransformer<mbgl::Color, MGLColor *>().toDataDrivenStyleValue(self.rawLayer->getDefaultCircleStrokeColor());
+    }
+    return MGLStyleValueTransformer<mbgl::Color, MGLColor *>().toDataDrivenStyleValue(propertyValue);
 }
 
 - (void)setCircleStrokeOpacity:(MGLStyleValue<NSNumber *> *)circleStrokeOpacity {
     MGLAssertStyleLayerIsValid();
 
-    auto mbglValue = MGLStyleValueTransformer<float, NSNumber *>().toPropertyValue(circleStrokeOpacity);
+    auto mbglValue = MGLStyleValueTransformer<float, NSNumber *>().toDataDrivenPropertyValue(circleStrokeOpacity);
     self.rawLayer->setCircleStrokeOpacity(mbglValue);
 }
 
 - (MGLStyleValue<NSNumber *> *)circleStrokeOpacity {
     MGLAssertStyleLayerIsValid();
 
-    auto propertyValue = self.rawLayer->getCircleStrokeOpacity() ?: self.rawLayer->getDefaultCircleStrokeOpacity();
-    return MGLStyleValueTransformer<float, NSNumber *>().toStyleValue(propertyValue);
+    auto propertyValue = self.rawLayer->getCircleStrokeOpacity();
+    if (propertyValue.isUndefined()) {
+        return MGLStyleValueTransformer<float, NSNumber *>().toDataDrivenStyleValue(self.rawLayer->getDefaultCircleStrokeOpacity());
+    }
+    return MGLStyleValueTransformer<float, NSNumber *>().toDataDrivenStyleValue(propertyValue);
 }
 
 - (void)setCircleStrokeWidth:(MGLStyleValue<NSNumber *> *)circleStrokeWidth {
     MGLAssertStyleLayerIsValid();
 
-    auto mbglValue = MGLStyleValueTransformer<float, NSNumber *>().toPropertyValue(circleStrokeWidth);
+    auto mbglValue = MGLStyleValueTransformer<float, NSNumber *>().toDataDrivenPropertyValue(circleStrokeWidth);
     self.rawLayer->setCircleStrokeWidth(mbglValue);
 }
 
 - (MGLStyleValue<NSNumber *> *)circleStrokeWidth {
     MGLAssertStyleLayerIsValid();
 
-    auto propertyValue = self.rawLayer->getCircleStrokeWidth() ?: self.rawLayer->getDefaultCircleStrokeWidth();
-    return MGLStyleValueTransformer<float, NSNumber *>().toStyleValue(propertyValue);
+    auto propertyValue = self.rawLayer->getCircleStrokeWidth();
+    if (propertyValue.isUndefined()) {
+        return MGLStyleValueTransformer<float, NSNumber *>().toDataDrivenStyleValue(self.rawLayer->getDefaultCircleStrokeWidth());
+    }
+    return MGLStyleValueTransformer<float, NSNumber *>().toDataDrivenStyleValue(propertyValue);
 }
 
 - (void)setCircleTranslation:(MGLStyleValue<NSValue *> *)circleTranslation {
     MGLAssertStyleLayerIsValid();
 
-    auto mbglValue = MGLStyleValueTransformer<std::array<float, 2>, NSValue *>().toPropertyValue(circleTranslation);
+    auto mbglValue = MGLStyleValueTransformer<std::array<float, 2>, NSValue *>().toInterpolatablePropertyValue(circleTranslation);
     self.rawLayer->setCircleTranslate(mbglValue);
 }
 
 - (MGLStyleValue<NSValue *> *)circleTranslation {
     MGLAssertStyleLayerIsValid();
 
-    auto propertyValue = self.rawLayer->getCircleTranslate() ?: self.rawLayer->getDefaultCircleTranslate();
+    auto propertyValue = self.rawLayer->getCircleTranslate();
+    if (propertyValue.isUndefined()) {
+        return MGLStyleValueTransformer<std::array<float, 2>, NSValue *>().toStyleValue(self.rawLayer->getDefaultCircleTranslate());
+    }
     return MGLStyleValueTransformer<std::array<float, 2>, NSValue *>().toStyleValue(propertyValue);
 }
 
@@ -283,7 +310,10 @@ namespace mbgl {
 - (MGLStyleValue<NSValue *> *)circleTranslationAnchor {
     MGLAssertStyleLayerIsValid();
 
-    auto propertyValue = self.rawLayer->getCircleTranslateAnchor() ?: self.rawLayer->getDefaultCircleTranslateAnchor();
+    auto propertyValue = self.rawLayer->getCircleTranslateAnchor();
+    if (propertyValue.isUndefined()) {
+        return MGLStyleValueTransformer<mbgl::style::TranslateAnchorType, NSValue *, mbgl::style::TranslateAnchorType, MGLCircleTranslationAnchor>().toEnumStyleValue(self.rawLayer->getDefaultCircleTranslateAnchor());
+    }
     return MGLStyleValueTransformer<mbgl::style::TranslateAnchorType, NSValue *, mbgl::style::TranslateAnchorType, MGLCircleTranslationAnchor>().toEnumStyleValue(propertyValue);
 }
 

platform/darwin/src/MGLFillStyleLayer.h

@@ -27,7 +27,7 @@ typedef NS_ENUM(NSUInteger, MGLFillTranslationAnchor) {
 /**
  An `MGLFillStyleLayer` is a style layer that renders one or more filled (and
  optionally stroked) polygons on the map.
-
+ 
  Use a fill style layer to configure the visual appearance of polygon or
  multipolygon features in vector tiles loaded by an `MGLVectorSource` object or
  `MGLPolygon`, `MGLPolygonFeature`, `MGLMultiPolygon`, or
@@ -56,11 +56,11 @@ MGL_EXPORT
 
 /**
  Whether or not the fill should be antialiased.
-
+ 
  The default value of this property is an `MGLStyleValue` object containing an
  `NSNumber` object containing `YES`. Set this property to `nil` to reset it to
  the default value.
-
+ 
  This attribute corresponds to the <a
  href="https://www.mapbox.com/mapbox-gl-style-spec/#paint-fill-antialias"><code>fill-antialias</code></a>
  layout property in the Mapbox Style Specification.
@@ -72,11 +72,11 @@ MGL_EXPORT
 #if TARGET_OS_IPHONE
 /**
  The color of the filled part of this layer.
-
+ 
  The default value of this property is an `MGLStyleValue` object containing
  `UIColor.blackColor`. Set this property to `nil` to reset it to the default
  value.
-
+ 
  This property is only applied to the style if `fillPattern` is set to `nil`.
  Otherwise, it is ignored.
  */
@@ -84,11 +84,11 @@ MGL_EXPORT
 #else
 /**
  The color of the filled part of this layer.
-
+ 
  The default value of this property is an `MGLStyleValue` object containing
  `NSColor.blackColor`. Set this property to `nil` to reset it to the default
  value.
-
+ 
  This property is only applied to the style if `fillPattern` is set to `nil`.
  Otherwise, it is ignored.
  */
@@ -98,7 +98,7 @@ MGL_EXPORT
 /**
  The opacity of the entire fill layer. In contrast to the `fillColor`, this
  value will also affect the 1pt stroke around the fill, if the stroke is used.
-
+ 
  The default value of this property is an `MGLStyleValue` object containing an
  `NSNumber` object containing the float `1`. Set this property to `nil` to reset
  it to the default value.
@@ -108,7 +108,7 @@ MGL_EXPORT
 #if TARGET_OS_IPHONE
 /**
  The outline color of the fill. Matches the value of `fillColor` if unspecified.
-
+ 
  This property is only applied to the style if `fillPattern` is set to `nil`,
  and `fillAntialiased` is set to an `MGLStyleValue` object containing an
  `NSNumber` object containing `YES`. Otherwise, it is ignored.
@@ -117,7 +117,7 @@ MGL_EXPORT
 #else
 /**
  The outline color of the fill. Matches the value of `fillColor` if unspecified.
-
+ 
  This property is only applied to the style if `fillPattern` is set to `nil`,
  and `fillAntialiased` is set to an `MGLStyleValue` object containing an
  `NSNumber` object containing `YES`. Otherwise, it is ignored.
@@ -134,13 +134,13 @@ MGL_EXPORT
 #if TARGET_OS_IPHONE
 /**
  The geometry's offset.
-
+ 
  This property is measured in points.
-
+ 
  The default value of this property is an `MGLStyleValue` object containing an
  `NSValue` object containing a `CGVector` struct set to 0 points rightward and 0
  points downward. Set this property to `nil` to reset it to the default value.
-
+ 
  This attribute corresponds to the <a
  href="https://www.mapbox.com/mapbox-gl-style-spec/#paint-fill-translate"><code>fill-translate</code></a>
  layout property in the Mapbox Style Specification.
@@ -149,13 +149,13 @@ MGL_EXPORT
 #else
 /**
  The geometry's offset.
-
+ 
  This property is measured in points.
-
+ 
  The default value of this property is an `MGLStyleValue` object containing an
  `NSValue` object containing a `CGVector` struct set to 0 points rightward and 0
  points upward. Set this property to `nil` to reset it to the default value.
-
+ 
  This attribute corresponds to the <a
  href="https://www.mapbox.com/mapbox-gl-style-spec/#paint-fill-translate"><code>fill-translate</code></a>
  layout property in the Mapbox Style Specification.
@@ -167,14 +167,14 @@ MGL_EXPORT
 
 /**
  Controls the translation reference point.
-
+ 
  The default value of this property is an `MGLStyleValue` object containing an
  `NSValue` object containing `MGLFillTranslationAnchorMap`. Set this property to
  `nil` to reset it to the default value.
-
+ 
  This property is only applied to the style if `fillTranslation` is non-`nil`.
  Otherwise, it is ignored.
-
+ 
  This attribute corresponds to the <a
  href="https://www.mapbox.com/mapbox-gl-style-spec/#paint-fill-translate-anchor"><code>fill-translate-anchor</code></a>
  layout property in the Mapbox Style Specification.

platform/darwin/src/MGLFillStyleLayer.mm

@@ -138,7 +138,10 @@ namespace mbgl {
 - (MGLStyleValue<NSNumber *> *)isFillAntialiased {
     MGLAssertStyleLayerIsValid();
 
-    auto propertyValue = self.rawLayer->getFillAntialias() ?: self.rawLayer->getDefaultFillAntialias();
+    auto propertyValue = self.rawLayer->getFillAntialias();
+    if (propertyValue.isUndefined()) {
+        return MGLStyleValueTransformer<bool, NSNumber *>().toStyleValue(self.rawLayer->getDefaultFillAntialias());
+    }
     return MGLStyleValueTransformer<bool, NSNumber *>().toStyleValue(propertyValue);
 }
 
@@ -152,43 +155,52 @@ namespace mbgl {
 - (void)setFillColor:(MGLStyleValue<MGLColor *> *)fillColor {
     MGLAssertStyleLayerIsValid();
 
-    auto mbglValue = MGLStyleValueTransformer<mbgl::Color, MGLColor *>().toPropertyValue(fillColor);
+    auto mbglValue = MGLStyleValueTransformer<mbgl::Color, MGLColor *>().toDataDrivenPropertyValue(fillColor);
     self.rawLayer->setFillColor(mbglValue);
 }
 
 - (MGLStyleValue<MGLColor *> *)fillColor {
     MGLAssertStyleLayerIsValid();
 
-    auto propertyValue = self.rawLayer->getFillColor() ?: self.rawLayer->getDefaultFillColor();
-    return MGLStyleValueTransformer<mbgl::Color, MGLColor *>().toStyleValue(propertyValue);
+    auto propertyValue = self.rawLayer->getFillColor();
+    if (propertyValue.isUndefined()) {
+        return MGLStyleValueTransformer<mbgl::Color, MGLColor *>().toDataDrivenStyleValue(self.rawLayer->getDefaultFillColor());
+    }
+    return MGLStyleValueTransformer<mbgl::Color, MGLColor *>().toDataDrivenStyleValue(propertyValue);
 }
 
 - (void)setFillOpacity:(MGLStyleValue<NSNumber *> *)fillOpacity {
     MGLAssertStyleLayerIsValid();
 
-    auto mbglValue = MGLStyleValueTransformer<float, NSNumber *>().toPropertyValue(fillOpacity);
+    auto mbglValue = MGLStyleValueTransformer<float, NSNumber *>().toDataDrivenPropertyValue(fillOpacity);
     self.rawLayer->setFillOpacity(mbglValue);
 }
 
 - (MGLStyleValue<NSNumber *> *)fillOpacity {
     MGLAssertStyleLayerIsValid();
 
-    auto propertyValue = self.rawLayer->getFillOpacity() ?: self.rawLayer->getDefaultFillOpacity();
-    return MGLStyleValueTransformer<float, NSNumber *>().toStyleValue(propertyValue);
+    auto propertyValue = self.rawLayer->getFillOpacity();
+    if (propertyValue.isUndefined()) {
+        return MGLStyleValueTransformer<float, NSNumber *>().toDataDrivenStyleValue(self.rawLayer->getDefaultFillOpacity());
+    }
+    return MGLStyleValueTransformer<float, NSNumber *>().toDataDrivenStyleValue(propertyValue);
 }
 
 - (void)setFillOutlineColor:(MGLStyleValue<MGLColor *> *)fillOutlineColor {
     MGLAssertStyleLayerIsValid();
 
-    auto mbglValue = MGLStyleValueTransformer<mbgl::Color, MGLColor *>().toPropertyValue(fillOutlineColor);
+    auto mbglValue = MGLStyleValueTransformer<mbgl::Color, MGLColor *>().toDataDrivenPropertyValue(fillOutlineColor);
     self.rawLayer->setFillOutlineColor(mbglValue);
 }
 
 - (MGLStyleValue<MGLColor *> *)fillOutlineColor {
     MGLAssertStyleLayerIsValid();
 
-    auto propertyValue = self.rawLayer->getFillOutlineColor() ?: self.rawLayer->getDefaultFillOutlineColor();
-    return MGLStyleValueTransformer<mbgl::Color, MGLColor *>().toStyleValue(propertyValue);
+    auto propertyValue = self.rawLayer->getFillOutlineColor();
+    if (propertyValue.isUndefined()) {
+        return MGLStyleValueTransformer<mbgl::Color, MGLColor *>().toDataDrivenStyleValue(self.rawLayer->getDefaultFillOutlineColor());
+    }
+    return MGLStyleValueTransformer<mbgl::Color, MGLColor *>().toDataDrivenStyleValue(propertyValue);
 }
 
 - (void)setFillPattern:(MGLStyleValue<NSString *> *)fillPattern {
@@ -201,21 +213,27 @@ namespace mbgl {
 - (MGLStyleValue<NSString *> *)fillPattern {
     MGLAssertStyleLayerIsValid();
 
-    auto propertyValue = self.rawLayer->getFillPattern() ?: self.rawLayer->getDefaultFillPattern();
+    auto propertyValue = self.rawLayer->getFillPattern();
+    if (propertyValue.isUndefined()) {
+        return MGLStyleValueTransformer<std::string, NSString *>().toStyleValue(self.rawLayer->getDefaultFillPattern());
+    }
     return MGLStyleValueTransformer<std::string, NSString *>().toStyleValue(propertyValue);
 }
 
 - (void)setFillTranslation:(MGLStyleValue<NSValue *> *)fillTranslation {
     MGLAssertStyleLayerIsValid();
 
-    auto mbglValue = MGLStyleValueTransformer<std::array<float, 2>, NSValue *>().toPropertyValue(fillTranslation);
+    auto mbglValue = MGLStyleValueTransformer<std::array<float, 2>, NSValue *>().toInterpolatablePropertyValue(fillTranslation);
     self.rawLayer->setFillTranslate(mbglValue);
 }
 
 - (MGLStyleValue<NSValue *> *)fillTranslation {
     MGLAssertStyleLayerIsValid();
 
-    auto propertyValue = self.rawLayer->getFillTranslate() ?: self.rawLayer->getDefaultFillTranslate();
+    auto propertyValue = self.rawLayer->getFillTranslate();
+    if (propertyValue.isUndefined()) {
+        return MGLStyleValueTransformer<std::array<float, 2>, NSValue *>().toStyleValue(self.rawLayer->getDefaultFillTranslate());
+    }
     return MGLStyleValueTransformer<std::array<float, 2>, NSValue *>().toStyleValue(propertyValue);
 }
 
@@ -236,7 +254,10 @@ namespace mbgl {
 - (MGLStyleValue<NSValue *> *)fillTranslationAnchor {
     MGLAssertStyleLayerIsValid();
 
-    auto propertyValue = self.rawLayer->getFillTranslateAnchor() ?: self.rawLayer->getDefaultFillTranslateAnchor();
+    auto propertyValue = self.rawLayer->getFillTranslateAnchor();
+    if (propertyValue.isUndefined()) {
+        return MGLStyleValueTransformer<mbgl::style::TranslateAnchorType, NSValue *, mbgl::style::TranslateAnchorType, MGLFillTranslationAnchor>().toEnumStyleValue(self.rawLayer->getDefaultFillTranslateAnchor());
+    }
     return MGLStyleValueTransformer<mbgl::style::TranslateAnchorType, NSValue *, mbgl::style::TranslateAnchorType, MGLFillTranslationAnchor>().toEnumStyleValue(propertyValue);
 }
 

platform/darwin/src/MGLLineStyleLayer.h

@@ -77,7 +77,7 @@ typedef NS_ENUM(NSUInteger, MGLLineTranslationAnchor) {
 /**
  An `MGLLineStyleLayer` is a style layer that renders one or more stroked
  polylines on the map.
-
+ 
  Use a line style layer to configure the visual appearance of polyline or
  multipolyline features in vector tiles loaded by an `MGLVectorSource` object or
  `MGLPolyline`, `MGLPolylineFeature`, `MGLMultiPolyline`, or
@@ -111,7 +111,7 @@ MGL_EXPORT
 
 /**
  The display of line endings.
-
+ 
  The default value of this property is an `MGLStyleValue` object containing an
  `NSValue` object containing `MGLLineCapButt`. Set this property to `nil` to
  reset it to the default value.
@@ -120,7 +120,7 @@ MGL_EXPORT
 
 /**
  The display of lines when joining.
-
+ 
  The default value of this property is an `MGLStyleValue` object containing an
  `NSValue` object containing `MGLLineJoinMiter`. Set this property to `nil` to
  reset it to the default value.
@@ -129,11 +129,11 @@ MGL_EXPORT
 
 /**
  Used to automatically convert miter joins to bevel joins for sharp angles.
-
+ 
  The default value of this property is an `MGLStyleValue` object containing an
  `NSNumber` object containing the float `2`. Set this property to `nil` to reset
  it to the default value.
-
+ 
  This property is only applied to the style if `lineJoin` is set to an
  `MGLStyleValue` object containing an `NSValue` object containing
  `MGLLineJoinMiter`. Otherwise, it is ignored.
@@ -142,11 +142,11 @@ MGL_EXPORT
 
 /**
  Used to automatically convert round joins to miter joins for shallow angles.
-
+ 
  The default value of this property is an `MGLStyleValue` object containing an
  `NSNumber` object containing the float `1.05`. Set this property to `nil` to
  reset it to the default value.
-
+ 
  This property is only applied to the style if `lineJoin` is set to an
  `MGLStyleValue` object containing an `NSValue` object containing
  `MGLLineJoinRound`. Otherwise, it is ignored.
@@ -157,9 +157,9 @@ MGL_EXPORT
 
 /**
  Blur applied to the line, in points.
-
+ 
  This property is measured in points.
-
+ 
  The default value of this property is an `MGLStyleValue` object containing an
  `NSNumber` object containing the float `0`. Set this property to `nil` to reset
  it to the default value.
@@ -169,11 +169,11 @@ MGL_EXPORT
 #if TARGET_OS_IPHONE
 /**
  The color with which the line will be drawn.
-
+ 
  The default value of this property is an `MGLStyleValue` object containing
  `UIColor.blackColor`. Set this property to `nil` to reset it to the default
  value.
-
+ 
  This property is only applied to the style if `linePattern` is set to `nil`.
  Otherwise, it is ignored.
  */
@@ -181,11 +181,11 @@ MGL_EXPORT
 #else
 /**
  The color with which the line will be drawn.
-
+ 
  The default value of this property is an `MGLStyleValue` object containing
  `NSColor.blackColor`. Set this property to `nil` to reset it to the default
  value.
-
+ 
  This property is only applied to the style if `linePattern` is set to `nil`.
  Otherwise, it is ignored.
  */
@@ -196,12 +196,12 @@ MGL_EXPORT
  Specifies the lengths of the alternating dashes and gaps that form the dash
  pattern. The lengths are later scaled by the line width. To convert a dash
  length to points, multiply the length by the current line width.
-
+ 
  This property is measured in line widths.
-
+ 
  This property is only applied to the style if `linePattern` is set to `nil`.
  Otherwise, it is ignored.
-
+ 
  This attribute corresponds to the <a
  href="https://www.mapbox.com/mapbox-gl-style-spec/#paint-line-dasharray"><code>line-dasharray</code></a>
  layout property in the Mapbox Style Specification.
@@ -213,9 +213,9 @@ MGL_EXPORT
 /**
  Draws a line casing outside of a line's actual path. Value indicates the width
  of the inner gap.
-
+ 
  This property is measured in points.
-
+ 
  The default value of this property is an `MGLStyleValue` object containing an
  `NSNumber` object containing the float `0`. Set this property to `nil` to reset
  it to the default value.
@@ -227,9 +227,9 @@ MGL_EXPORT
  the right, relative to the direction of the line, and a negative value to the
  left. For polygon features, a positive value results in an inset, and a
  negative value results in an outset.
-
+ 
  This property is measured in points.
-
+ 
  The default value of this property is an `MGLStyleValue` object containing an
  `NSNumber` object containing the float `0`. Set this property to `nil` to reset
  it to the default value.
@@ -238,7 +238,7 @@ MGL_EXPORT
 
 /**
  The opacity at which the line will be drawn.
-
+ 
  The default value of this property is an `MGLStyleValue` object containing an
  `NSNumber` object containing the float `1`. Set this property to `nil` to reset
  it to the default value.
@@ -254,13 +254,13 @@ MGL_EXPORT
 #if TARGET_OS_IPHONE
 /**
  The geometry's offset.
-
+ 
  This property is measured in points.
-
+ 
  The default value of this property is an `MGLStyleValue` object containing an
  `NSValue` object containing a `CGVector` struct set to 0 points rightward and 0
  points downward. Set this property to `nil` to reset it to the default value.
-
+ 
  This attribute corresponds to the <a
  href="https://www.mapbox.com/mapbox-gl-style-spec/#paint-line-translate"><code>line-translate</code></a>
  layout property in the Mapbox Style Specification.
@@ -269,13 +269,13 @@ MGL_EXPORT
 #else
 /**
  The geometry's offset.
-
+ 
  This property is measured in points.
-
+ 
  The default value of this property is an `MGLStyleValue` object containing an
  `NSValue` object containing a `CGVector` struct set to 0 points rightward and 0
  points upward. Set this property to `nil` to reset it to the default value.
-
+ 
  This attribute corresponds to the <a
  href="https://www.mapbox.com/mapbox-gl-style-spec/#paint-line-translate"><code>line-translate</code></a>
  layout property in the Mapbox Style Specification.
@@ -287,14 +287,14 @@ MGL_EXPORT
 
 /**
  Controls the translation reference point.
-
+ 
  The default value of this property is an `MGLStyleValue` object containing an
  `NSValue` object containing `MGLLineTranslationAnchorMap`. Set this property to
  `nil` to reset it to the default value.
-
+ 
  This property is only applied to the style if `lineTranslation` is non-`nil`.
  Otherwise, it is ignored.
-
+ 
  This attribute corresponds to the <a
  href="https://www.mapbox.com/mapbox-gl-style-spec/#paint-line-translate-anchor"><code>line-translate-anchor</code></a>
  layout property in the Mapbox Style Specification.
@@ -305,9 +305,9 @@ MGL_EXPORT
 
 /**
  Stroke thickness.
-
+ 
  This property is measured in points.
-
+ 
  The default value of this property is an `MGLStyleValue` object containing an
  `NSNumber` object containing the float `1`. Set this property to `nil` to reset
  it to the default value.

platform/darwin/src/MGLLineStyleLayer.mm

@@ -150,7 +150,10 @@ namespace mbgl {
 - (MGLStyleValue<NSValue *> *)lineCap {
     MGLAssertStyleLayerIsValid();
 
-    auto propertyValue = self.rawLayer->getLineCap() ?: self.rawLayer->getDefaultLineCap();
+    auto propertyValue = self.rawLayer->getLineCap();
+    if (propertyValue.isUndefined()) {
+        return MGLStyleValueTransformer<mbgl::style::LineCapType, NSValue *, mbgl::style::LineCapType, MGLLineCap>().toEnumStyleValue(self.rawLayer->getDefaultLineCap());
+    }
     return MGLStyleValueTransformer<mbgl::style::LineCapType, NSValue *, mbgl::style::LineCapType, MGLLineCap>().toEnumStyleValue(propertyValue);
 }
 
@@ -164,35 +167,44 @@ namespace mbgl {
 - (MGLStyleValue<NSValue *> *)lineJoin {
     MGLAssertStyleLayerIsValid();
 
-    auto propertyValue = self.rawLayer->getLineJoin() ?: self.rawLayer->getDefaultLineJoin();
+    auto propertyValue = self.rawLayer->getLineJoin();
+    if (propertyValue.isUndefined()) {
+        return MGLStyleValueTransformer<mbgl::style::LineJoinType, NSValue *, mbgl::style::LineJoinType, MGLLineJoin>().toEnumStyleValue(self.rawLayer->getDefaultLineJoin());
+    }
     return MGLStyleValueTransformer<mbgl::style::LineJoinType, NSValue *, mbgl::style::LineJoinType, MGLLineJoin>().toEnumStyleValue(propertyValue);
 }
 
 - (void)setLineMiterLimit:(MGLStyleValue<NSNumber *> *)lineMiterLimit {
     MGLAssertStyleLayerIsValid();
 
-    auto mbglValue = MGLStyleValueTransformer<float, NSNumber *>().toPropertyValue(lineMiterLimit);
+    auto mbglValue = MGLStyleValueTransformer<float, NSNumber *>().toInterpolatablePropertyValue(lineMiterLimit);
     self.rawLayer->setLineMiterLimit(mbglValue);
 }
 
 - (MGLStyleValue<NSNumber *> *)lineMiterLimit {
     MGLAssertStyleLayerIsValid();
 
-    auto propertyValue = self.rawLayer->getLineMiterLimit() ?: self.rawLayer->getDefaultLineMiterLimit();
+    auto propertyValue = self.rawLayer->getLineMiterLimit();
+    if (propertyValue.isUndefined()) {
+        return MGLStyleValueTransformer<float, NSNumber *>().toStyleValue(self.rawLayer->getDefaultLineMiterLimit());
+    }
     return MGLStyleValueTransformer<float, NSNumber *>().toStyleValue(propertyValue);
 }
 
 - (void)setLineRoundLimit:(MGLStyleValue<NSNumber *> *)lineRoundLimit {
     MGLAssertStyleLayerIsValid();
 
-    auto mbglValue = MGLStyleValueTransformer<float, NSNumber *>().toPropertyValue(lineRoundLimit);
+    auto mbglValue = MGLStyleValueTransformer<float, NSNumber *>().toInterpolatablePropertyValue(lineRoundLimit);
     self.rawLayer->setLineRoundLimit(mbglValue);
 }
 
 - (MGLStyleValue<NSNumber *> *)lineRoundLimit {
     MGLAssertStyleLayerIsValid();
 
-    auto propertyValue = self.rawLayer->getLineRoundLimit() ?: self.rawLayer->getDefaultLineRoundLimit();
+    auto propertyValue = self.rawLayer->getLineRoundLimit();
+    if (propertyValue.isUndefined()) {
+        return MGLStyleValueTransformer<float, NSNumber *>().toStyleValue(self.rawLayer->getDefaultLineRoundLimit());
+    }
     return MGLStyleValueTransformer<float, NSNumber *>().toStyleValue(propertyValue);
 }
 
@@ -201,29 +213,35 @@ namespace mbgl {
 - (void)setLineBlur:(MGLStyleValue<NSNumber *> *)lineBlur {
     MGLAssertStyleLayerIsValid();
 
-    auto mbglValue = MGLStyleValueTransformer<float, NSNumber *>().toPropertyValue(lineBlur);
+    auto mbglValue = MGLStyleValueTransformer<float, NSNumber *>().toDataDrivenPropertyValue(lineBlur);
     self.rawLayer->setLineBlur(mbglValue);
 }
 
 - (MGLStyleValue<NSNumber *> *)lineBlur {
     MGLAssertStyleLayerIsValid();
 
-    auto propertyValue = self.rawLayer->getLineBlur() ?: self.rawLayer->getDefaultLineBlur();
-    return MGLStyleValueTransformer<float, NSNumber *>().toStyleValue(propertyValue);
+    auto propertyValue = self.rawLayer->getLineBlur();
+    if (propertyValue.isUndefined()) {
+        return MGLStyleValueTransformer<float, NSNumber *>().toDataDrivenStyleValue(self.rawLayer->getDefaultLineBlur());
+    }
+    return MGLStyleValueTransformer<float, NSNumber *>().toDataDrivenStyleValue(propertyValue);
 }
 
 - (void)setLineColor:(MGLStyleValue<MGLColor *> *)lineColor {
     MGLAssertStyleLayerIsValid();
 
-    auto mbglValue = MGLStyleValueTransformer<mbgl::Color, MGLColor *>().toPropertyValue(lineColor);
+    auto mbglValue = MGLStyleValueTransformer<mbgl::Color, MGLColor *>().toDataDrivenPropertyValue(lineColor);
     self.rawLayer->setLineColor(mbglValue);
 }
 
 - (MGLStyleValue<MGLColor *> *)lineColor {
     MGLAssertStyleLayerIsValid();
 
-    auto propertyValue = self.rawLayer->getLineColor() ?: self.rawLayer->getDefaultLineColor();
-    return MGLStyleValueTransformer<mbgl::Color, MGLColor *>().toStyleValue(propertyValue);
+    auto propertyValue = self.rawLayer->getLineColor();
+    if (propertyValue.isUndefined()) {
+        return MGLStyleValueTransformer<mbgl::Color, MGLColor *>().toDataDrivenStyleValue(self.rawLayer->getDefaultLineColor());
+    }
+    return MGLStyleValueTransformer<mbgl::Color, MGLColor *>().toDataDrivenStyleValue(propertyValue);
 }
 
 - (void)setLineDashPattern:(MGLStyleValue<NSArray<NSNumber *> *> *)lineDashPattern {
@@ -236,7 +254,10 @@ namespace mbgl {
 - (MGLStyleValue<NSArray<NSNumber *> *> *)lineDashPattern {
     MGLAssertStyleLayerIsValid();
 
-    auto propertyValue = self.rawLayer->getLineDasharray() ?: self.rawLayer->getDefaultLineDasharray();
+    auto propertyValue = self.rawLayer->getLineDasharray();
+    if (propertyValue.isUndefined()) {
+        return MGLStyleValueTransformer<std::vector<float>, NSArray<NSNumber *> *, float>().toStyleValue(self.rawLayer->getDefaultLineDasharray());
+    }
     return MGLStyleValueTransformer<std::vector<float>, NSArray<NSNumber *> *, float>().toStyleValue(propertyValue);
 }
 
@@ -250,43 +271,52 @@ namespace mbgl {
 - (void)setLineGapWidth:(MGLStyleValue<NSNumber *> *)lineGapWidth {
     MGLAssertStyleLayerIsValid();
 
-    auto mbglValue = MGLStyleValueTransformer<float, NSNumber *>().toPropertyValue(lineGapWidth);
+    auto mbglValue = MGLStyleValueTransformer<float, NSNumber *>().toDataDrivenPropertyValue(lineGapWidth);
     self.rawLayer->setLineGapWidth(mbglValue);
 }
 
 - (MGLStyleValue<NSNumber *> *)lineGapWidth {
     MGLAssertStyleLayerIsValid();
 
-    auto propertyValue = self.rawLayer->getLineGapWidth() ?: self.rawLayer->getDefaultLineGapWidth();
-    return MGLStyleValueTransformer<float, NSNumber *>().toStyleValue(propertyValue);
+    auto propertyValue = self.rawLayer->getLineGapWidth();
+    if (propertyValue.isUndefined()) {
+        return MGLStyleValueTransformer<float, NSNumber *>().toDataDrivenStyleValue(self.rawLayer->getDefaultLineGapWidth());
+    }
+    return MGLStyleValueTransformer<float, NSNumber *>().toDataDrivenStyleValue(propertyValue);
 }
 
 - (void)setLineOffset:(MGLStyleValue<NSNumber *> *)lineOffset {
     MGLAssertStyleLayerIsValid();
 
-    auto mbglValue = MGLStyleValueTransformer<float, NSNumber *>().toPropertyValue(lineOffset);
+    auto mbglValue = MGLStyleValueTransformer<float, NSNumber *>().toDataDrivenPropertyValue(lineOffset);
     self.rawLayer->setLineOffset(mbglValue);
 }
 
 - (MGLStyleValue<NSNumber *> *)lineOffset {
     MGLAssertStyleLayerIsValid();
 
-    auto propertyValue = self.rawLayer->getLineOffset() ?: self.rawLayer->getDefaultLineOffset();
-    return MGLStyleValueTransformer<float, NSNumber *>().toStyleValue(propertyValue);
+    auto propertyValue = self.rawLayer->getLineOffset();
+    if (propertyValue.isUndefined()) {
+        return MGLStyleValueTransformer<float, NSNumber *>().toDataDrivenStyleValue(self.rawLayer->getDefaultLineOffset());
+    }
+    return MGLStyleValueTransformer<float, NSNumber *>().toDataDrivenStyleValue(propertyValue);
 }
 
 - (void)setLineOpacity:(MGLStyleValue<NSNumber *> *)lineOpacity {
     MGLAssertStyleLayerIsValid();
 
-    auto mbglValue = MGLStyleValueTransformer<float, NSNumber *>().toPropertyValue(lineOpacity);
+    auto mbglValue = MGLStyleValueTransformer<float, NSNumber *>().toDataDrivenPropertyValue(lineOpacity);
     self.rawLayer->setLineOpacity(mbglValue);
 }
 
 - (MGLStyleValue<NSNumber *> *)lineOpacity {
     MGLAssertStyleLayerIsValid();
 
-    auto propertyValue = self.rawLayer->getLineOpacity() ?: self.rawLayer->getDefaultLineOpacity();
-    return MGLStyleValueTransformer<float, NSNumber *>().toStyleValue(propertyValue);
+    auto propertyValue = self.rawLayer->getLineOpacity();
+    if (propertyValue.isUndefined()) {
+        return MGLStyleValueTransformer<float, NSNumber *>().toDataDrivenStyleValue(self.rawLayer->getDefaultLineOpacity());
+    }
+    return MGLStyleValueTransformer<float, NSNumber *>().toDataDrivenStyleValue(propertyValue);
 }
 
 - (void)setLinePattern:(MGLStyleValue<NSString *> *)linePattern {
@@ -299,21 +329,27 @@ namespace mbgl {
 - (MGLStyleValue<NSString *> *)linePattern {
     MGLAssertStyleLayerIsValid();
 
-    auto propertyValue = self.rawLayer->getLinePattern() ?: self.rawLayer->getDefaultLinePattern();
+    auto propertyValue = self.rawLayer->getLinePattern();
+    if (propertyValue.isUndefined()) {
+        return MGLStyleValueTransformer<std::string, NSString *>().toStyleValue(self.rawLayer->getDefaultLinePattern());
+    }
     return MGLStyleValueTransformer<std::string, NSString *>().toStyleValue(propertyValue);
 }
 
 - (void)setLineTranslation:(MGLStyleValue<NSValue *> *)lineTranslation {
     MGLAssertStyleLayerIsValid();
 
-    auto mbglValue = MGLStyleValueTransformer<std::array<float, 2>, NSValue *>().toPropertyValue(lineTranslation);
+    auto mbglValue = MGLStyleValueTransformer<std::array<float, 2>, NSValue *>().toInterpolatablePropertyValue(lineTranslation);
     self.rawLayer->setLineTranslate(mbglValue);
 }
 
 - (MGLStyleValue<NSValue *> *)lineTranslation {
     MGLAssertStyleLayerIsValid();
 
-    auto propertyValue = self.rawLayer->getLineTranslate() ?: self.rawLayer->getDefaultLineTranslate();
+    auto propertyValue = self.rawLayer->getLineTranslate();
+    if (propertyValue.isUndefined()) {
+        return MGLStyleValueTransformer<std::array<float, 2>, NSValue *>().toStyleValue(self.rawLayer->getDefaultLineTranslate());
+    }
     return MGLStyleValueTransformer<std::array<float, 2>, NSValue *>().toStyleValue(propertyValue);
 }
 
@@ -334,7 +370,10 @@ namespace mbgl {
 - (MGLStyleValue<NSValue *> *)lineTranslationAnchor {
     MGLAssertStyleLayerIsValid();
 
-    auto propertyValue = self.rawLayer->getLineTranslateAnchor() ?: self.rawLayer->getDefaultLineTranslateAnchor();
+    auto propertyValue = self.rawLayer->getLineTranslateAnchor();
+    if (propertyValue.isUndefined()) {
+        return MGLStyleValueTransformer<mbgl::style::TranslateAnchorType, NSValue *, mbgl::style::TranslateAnchorType, MGLLineTranslationAnchor>().toEnumStyleValue(self.rawLayer->getDefaultLineTranslateAnchor());
+    }
     return MGLStyleValueTransformer<mbgl::style::TranslateAnchorType, NSValue *, mbgl::style::TranslateAnchorType, MGLLineTranslationAnchor>().toEnumStyleValue(propertyValue);
 }
 
@@ -348,14 +387,17 @@ namespace mbgl {
 - (void)setLineWidth:(MGLStyleValue<NSNumber *> *)lineWidth {
     MGLAssertStyleLayerIsValid();
 
-    auto mbglValue = MGLStyleValueTransformer<float, NSNumber *>().toPropertyValue(lineWidth);
+    auto mbglValue = MGLStyleValueTransformer<float, NSNumber *>().toInterpolatablePropertyValue(lineWidth);
     self.rawLayer->setLineWidth(mbglValue);
 }
 
 - (MGLStyleValue<NSNumber *> *)lineWidth {
     MGLAssertStyleLayerIsValid();
 
-    auto propertyValue = self.rawLayer->getLineWidth() ?: self.rawLayer->getDefaultLineWidth();
+    auto propertyValue = self.rawLayer->getLineWidth();
+    if (propertyValue.isUndefined()) {
+        return MGLStyleValueTransformer<float, NSNumber *>().toStyleValue(self.rawLayer->getDefaultLineWidth());
+    }
     return MGLStyleValueTransformer<float, NSNumber *>().toStyleValue(propertyValue);
 }
 

platform/darwin/src/MGLRasterStyleLayer.h

@@ -9,7 +9,7 @@ NS_ASSUME_NONNULL_BEGIN
 
 /**
  An `MGLRasterStyleLayer` is a style layer that renders raster tiles on the map.
-
+ 
  Use a raster style layer to configure the color parameters of raster tiles
  loaded by an `MGLRasterSource` object. For example, you could use a raster
  style layer to render <a href="https://www.mapbox.com/satellite/">Mapbox
@@ -41,11 +41,11 @@ MGL_EXPORT
 /**
  Increase or reduce the brightness of the image. The value is the maximum
  brightness.
-
+ 
  The default value of this property is an `MGLStyleValue` object containing an
  `NSNumber` object containing the float `1`. Set this property to `nil` to reset
  it to the default value.
-
+ 
  This attribute corresponds to the <a
  href="https://www.mapbox.com/mapbox-gl-style-spec/#paint-raster-brightness-max"><code>raster-brightness-max</code></a>
  layout property in the Mapbox Style Specification.
@@ -57,11 +57,11 @@ MGL_EXPORT
 /**
  Increase or reduce the brightness of the image. The value is the minimum
  brightness.
-
+ 
  The default value of this property is an `MGLStyleValue` object containing an
  `NSNumber` object containing the float `0`. Set this property to `nil` to reset
  it to the default value.
-
+ 
  This attribute corresponds to the <a
  href="https://www.mapbox.com/mapbox-gl-style-spec/#paint-raster-brightness-min"><code>raster-brightness-min</code></a>
  layout property in the Mapbox Style Specification.
@@ -72,7 +72,7 @@ MGL_EXPORT
 
 /**
  Increase or reduce the contrast of the image.
-
+ 
  The default value of this property is an `MGLStyleValue` object containing an
  `NSNumber` object containing the float `0`. Set this property to `nil` to reset
  it to the default value.
@@ -81,9 +81,9 @@ MGL_EXPORT
 
 /**
  Fade duration when a new tile is added.
-
+ 
  This property is measured in milliseconds.
-
+ 
  The default value of this property is an `MGLStyleValue` object containing an
  `NSNumber` object containing the float `300`. Set this property to `nil` to
  reset it to the default value.
@@ -92,13 +92,13 @@ MGL_EXPORT
 
 /**
  Rotates hues around the color wheel.
-
+ 
  This property is measured in degrees.
-
+ 
  The default value of this property is an `MGLStyleValue` object containing an
  `NSNumber` object containing the float `0`. Set this property to `nil` to reset
  it to the default value.
-
+ 
  This attribute corresponds to the <a
  href="https://www.mapbox.com/mapbox-gl-style-spec/#paint-raster-hue-rotate"><code>raster-hue-rotate</code></a>
  layout property in the Mapbox Style Specification.
@@ -109,7 +109,7 @@ MGL_EXPORT
 
 /**
  The opacity at which the image will be drawn.
-
+ 
  The default value of this property is an `MGLStyleValue` object containing an
  `NSNumber` object containing the float `1`. Set this property to `nil` to reset
  it to the default value.
@@ -118,7 +118,7 @@ MGL_EXPORT
 
 /**
  Increase or reduce the saturation of the image.
-
+ 
  The default value of this property is an `MGLStyleValue` object containing an
  `NSNumber` object containing the float `0`. Set this property to `nil` to reset
  it to the default value.

platform/darwin/src/MGLRasterStyleLayer.mm

@@ -93,14 +93,17 @@
 - (void)setMaximumRasterBrightness:(MGLStyleValue<NSNumber *> *)maximumRasterBrightness {
     MGLAssertStyleLayerIsValid();
 
-    auto mbglValue = MGLStyleValueTransformer<float, NSNumber *>().toPropertyValue(maximumRasterBrightness);
+    auto mbglValue = MGLStyleValueTransformer<float, NSNumber *>().toInterpolatablePropertyValue(maximumRasterBrightness);
     self.rawLayer->setRasterBrightnessMax(mbglValue);
 }
 
 - (MGLStyleValue<NSNumber *> *)maximumRasterBrightness {
     MGLAssertStyleLayerIsValid();
 
-    auto propertyValue = self.rawLayer->getRasterBrightnessMax() ?: self.rawLayer->getDefaultRasterBrightnessMax();
+    auto propertyValue = self.rawLayer->getRasterBrightnessMax();
+    if (propertyValue.isUndefined()) {
+        return MGLStyleValueTransformer<float, NSNumber *>().toStyleValue(self.rawLayer->getDefaultRasterBrightnessMax());
+    }
     return MGLStyleValueTransformer<float, NSNumber *>().toStyleValue(propertyValue);
 }
 
@@ -114,14 +117,17 @@
 - (void)setMinimumRasterBrightness:(MGLStyleValue<NSNumber *> *)minimumRasterBrightness {
     MGLAssertStyleLayerIsValid();
 
-    auto mbglValue = MGLStyleValueTransformer<float, NSNumber *>().toPropertyValue(minimumRasterBrightness);
+    auto mbglValue = MGLStyleValueTransformer<float, NSNumber *>().toInterpolatablePropertyValue(minimumRasterBrightness);
     self.rawLayer->setRasterBrightnessMin(mbglValue);
 }
 
 - (MGLStyleValue<NSNumber *> *)minimumRasterBrightness {
     MGLAssertStyleLayerIsValid();
 
-    auto propertyValue = self.rawLayer->getRasterBrightnessMin() ?: self.rawLayer->getDefaultRasterBrightnessMin();
+    auto propertyValue = self.rawLayer->getRasterBrightnessMin();
+    if (propertyValue.isUndefined()) {
+        return MGLStyleValueTransformer<float, NSNumber *>().toStyleValue(self.rawLayer->getDefaultRasterBrightnessMin());
+    }
     return MGLStyleValueTransformer<float, NSNumber *>().toStyleValue(propertyValue);
 }
 
@@ -135,42 +141,51 @@
 - (void)setRasterContrast:(MGLStyleValue<NSNumber *> *)rasterContrast {
     MGLAssertStyleLayerIsValid();
 
-    auto mbglValue = MGLStyleValueTransformer<float, NSNumber *>().toPropertyValue(rasterContrast);
+    auto mbglValue = MGLStyleValueTransformer<float, NSNumber *>().toInterpolatablePropertyValue(rasterContrast);
     self.rawLayer->setRasterContrast(mbglValue);
 }
 
 - (MGLStyleValue<NSNumber *> *)rasterContrast {
     MGLAssertStyleLayerIsValid();
 
-    auto propertyValue = self.rawLayer->getRasterContrast() ?: self.rawLayer->getDefaultRasterContrast();
+    auto propertyValue = self.rawLayer->getRasterContrast();
+    if (propertyValue.isUndefined()) {
+        return MGLStyleValueTransformer<float, NSNumber *>().toStyleValue(self.rawLayer->getDefaultRasterContrast());
+    }
     return MGLStyleValueTransformer<float, NSNumber *>().toStyleValue(propertyValue);
 }
 
 - (void)setRasterFadeDuration:(MGLStyleValue<NSNumber *> *)rasterFadeDuration {
     MGLAssertStyleLayerIsValid();
 
-    auto mbglValue = MGLStyleValueTransformer<float, NSNumber *>().toPropertyValue(rasterFadeDuration);
+    auto mbglValue = MGLStyleValueTransformer<float, NSNumber *>().toInterpolatablePropertyValue(rasterFadeDuration);
     self.rawLayer->setRasterFadeDuration(mbglValue);
 }
 
 - (MGLStyleValue<NSNumber *> *)rasterFadeDuration {
     MGLAssertStyleLayerIsValid();
 
-    auto propertyValue = self.rawLayer->getRasterFadeDuration() ?: self.rawLayer->getDefaultRasterFadeDuration();
+    auto propertyValue = self.rawLayer->getRasterFadeDuration();
+    if (propertyValue.isUndefined()) {
+        return MGLStyleValueTransformer<float, NSNumber *>().toStyleValue(self.rawLayer->getDefaultRasterFadeDuration());
+    }
     return MGLStyleValueTransformer<float, NSNumber *>().toStyleValue(propertyValue);
 }
 
 - (void)setRasterHueRotation:(MGLStyleValue<NSNumber *> *)rasterHueRotation {
     MGLAssertStyleLayerIsValid();
 
-    auto mbglValue = MGLStyleValueTransformer<float, NSNumber *>().toPropertyValue(rasterHueRotation);
+    auto mbglValue = MGLStyleValueTransformer<float, NSNumber *>().toInterpolatablePropertyValue(rasterHueRotation);
     self.rawLayer->setRasterHueRotate(mbglValue);
 }
 
 - (MGLStyleValue<NSNumber *> *)rasterHueRotation {
     MGLAssertStyleLayerIsValid();
 
-    auto propertyValue = self.rawLayer->getRasterHueRotate() ?: self.rawLayer->getDefaultRasterHueRotate();
+    auto propertyValue = self.rawLayer->getRasterHueRotate();
+    if (propertyValue.isUndefined()) {
+        return MGLStyleValueTransformer<float, NSNumber *>().toStyleValue(self.rawLayer->getDefaultRasterHueRotate());
+    }
     return MGLStyleValueTransformer<float, NSNumber *>().toStyleValue(propertyValue);
 }
 
@@ -184,28 +199,34 @@
 - (void)setRasterOpacity:(MGLStyleValue<NSNumber *> *)rasterOpacity {
     MGLAssertStyleLayerIsValid();
 
-    auto mbglValue = MGLStyleValueTransformer<float, NSNumber *>().toPropertyValue(rasterOpacity);
+    auto mbglValue = MGLStyleValueTransformer<float, NSNumber *>().toInterpolatablePropertyValue(rasterOpacity);
     self.rawLayer->setRasterOpacity(mbglValue);
 }
 
 - (MGLStyleValue<NSNumber *> *)rasterOpacity {
     MGLAssertStyleLayerIsValid();
 
-    auto propertyValue = self.rawLayer->getRasterOpacity() ?: self.rawLayer->getDefaultRasterOpacity();
+    auto propertyValue = self.rawLayer->getRasterOpacity();
+    if (propertyValue.isUndefined()) {
+        return MGLStyleValueTransformer<float, NSNumber *>().toStyleValue(self.rawLayer->getDefaultRasterOpacity());
+    }
     return MGLStyleValueTransformer<float, NSNumber *>().toStyleValue(propertyValue);
 }
 
 - (void)setRasterSaturation:(MGLStyleValue<NSNumber *> *)rasterSaturation {
     MGLAssertStyleLayerIsValid();
 
-    auto mbglValue = MGLStyleValueTransformer<float, NSNumber *>().toPropertyValue(rasterSaturation);
+    auto mbglValue = MGLStyleValueTransformer<float, NSNumber *>().toInterpolatablePropertyValue(rasterSaturation);
     self.rawLayer->setRasterSaturation(mbglValue);
 }
 
 - (MGLStyleValue<NSNumber *> *)rasterSaturation {
     MGLAssertStyleLayerIsValid();
 
-    auto propertyValue = self.rawLayer->getRasterSaturation() ?: self.rawLayer->getDefaultRasterSaturation();
+    auto propertyValue = self.rawLayer->getRasterSaturation();
+    if (propertyValue.isUndefined()) {
+        return MGLStyleValueTransformer<float, NSNumber *>().toStyleValue(self.rawLayer->getDefaultRasterSaturation());
+    }
     return MGLStyleValueTransformer<float, NSNumber *>().toStyleValue(propertyValue);
 }
 

platform/darwin/src/MGLStyleLayer.mm.ejs

@@ -176,24 +176,42 @@ namespace mbgl {
 - (void)set<%- camelize(property.name) %>:(MGLStyleValue<<%- propertyType(property, true) %>> *)<%- objCName(property) %> {
     MGLAssertStyleLayerIsValid();
 
+<% if (property["property-function"]) { -%>
+    auto mbglValue = MGLStyleValueTransformer<<%- valueTransformerArguments(property).join(', ') %>>().toDataDrivenPropertyValue(<%- objCName(property) %>);
+<% } else { -%>
 <% if (property.type == "enum") { -%>
     auto mbglValue = MGLStyleValueTransformer<<%- mbglType(property) %>, NSValue *, <%- mbglType(property) %>, MGL<%- camelize(property.name) %>>().toEnumPropertyValue(<%- objCName(property) %>);
-    self.rawLayer->set<%- camelize(originalPropertyName(property)) %>(mbglValue);
-<% } else { -%>
+<% } else if (property.function == "piecewise-constant") { -%>
     auto mbglValue = MGLStyleValueTransformer<<%- valueTransformerArguments(property).join(', ') %>>().toPropertyValue(<%- objCName(property) %>);
-    self.rawLayer->set<%- camelize(originalPropertyName(property)) %>(mbglValue);
+<% } else { -%>
+    auto mbglValue = MGLStyleValueTransformer<<%- valueTransformerArguments(property).join(', ') %>>().toInterpolatablePropertyValue(<%- objCName(property) %>);
 <% } -%>
+<% } -%>
+    self.rawLayer->set<%- camelize(originalPropertyName(property)) %>(mbglValue);
 }
 
 - (MGLStyleValue<<%- propertyType(property, true) %>> *)<%- objCGetter(property) %> {
     MGLAssertStyleLayerIsValid();
 
-    auto propertyValue = self.rawLayer->get<%- camelize(originalPropertyName(property)) %>() ?: self.rawLayer->getDefault<%- camelize(originalPropertyName(property)) %>();
+    auto propertyValue = self.rawLayer->get<%- camelize(originalPropertyName(property)) %>();
+<% if (property["property-function"]) { -%>
+    if (propertyValue.isUndefined()) {
+        return MGLStyleValueTransformer<<%- valueTransformerArguments(property).join(', ') %>>().toDataDrivenStyleValue(self.rawLayer->getDefault<%- camelize(originalPropertyName(property)) %>());
+    }
+    return MGLStyleValueTransformer<<%- valueTransformerArguments(property).join(', ') %>>().toDataDrivenStyleValue(propertyValue);
+<% } else { -%>
 <% if (property.type == "enum") { -%>
+    if (propertyValue.isUndefined()) {
+        return MGLStyleValueTransformer<<%- mbglType(property) %>, NSValue *, <%- mbglType(property) %>, MGL<%- camelize(property.name) %>>().toEnumStyleValue(self.rawLayer->getDefault<%- camelize(originalPropertyName(property)) %>());
+    }
     return MGLStyleValueTransformer<<%- mbglType(property) %>, NSValue *, <%- mbglType(property) %>, MGL<%- camelize(property.name) %>>().toEnumStyleValue(propertyValue);
 <% } else { -%>
+    if (propertyValue.isUndefined()) {
+        return MGLStyleValueTransformer<<%- valueTransformerArguments(property).join(', ') %>>().toStyleValue(self.rawLayer->getDefault<%- camelize(originalPropertyName(property)) %>());
+    }
     return MGLStyleValueTransformer<<%- valueTransformerArguments(property).join(', ') %>>().toStyleValue(propertyValue);
 <% } -%>
+<% } -%>
 }
 
 <% if (property.original) { -%>
@@ -214,24 +232,42 @@ namespace mbgl {
 - (void)set<%- camelize(property.name) %>:(MGLStyleValue<<%- propertyType(property, true) %>> *)<%- objCName(property) %> {
     MGLAssertStyleLayerIsValid();
 
+<% if (property["property-function"]) { -%>
+    auto mbglValue = MGLStyleValueTransformer<<%- valueTransformerArguments(property).join(', ') %>>().toDataDrivenPropertyValue(<%- objCName(property) %>);
+<% } else { -%>
 <% if (property.type == "enum") { -%>
     auto mbglValue = MGLStyleValueTransformer<<%- mbglType(property) %>, NSValue *, <%- mbglType(property) %>, MGL<%- camelize(property.name) %>>().toEnumPropertyValue(<%- objCName(property) %>);
-    self.rawLayer->set<%- camelize(originalPropertyName(property)) %>(mbglValue);
-<% } else { -%>
+<% } else if (property.function == "piecewise-constant") { -%>
     auto mbglValue = MGLStyleValueTransformer<<%- valueTransformerArguments(property).join(', ') %>>().toPropertyValue(<%- objCName(property) %>);
-    self.rawLayer->set<%- camelize(originalPropertyName(property)) %>(mbglValue);
+<% } else { -%>
+    auto mbglValue = MGLStyleValueTransformer<<%- valueTransformerArguments(property).join(', ') %>>().toInterpolatablePropertyValue(<%- objCName(property) %>);
 <% } -%>
+<% } -%>
+    self.rawLayer->set<%- camelize(originalPropertyName(property)) %>(mbglValue);
 }
 
 - (MGLStyleValue<<%- propertyType(property, true) %>> *)<%- objCGetter(property) %> {
     MGLAssertStyleLayerIsValid();
 
-    auto propertyValue = self.rawLayer->get<%- camelize(originalPropertyName(property)) %>() ?: self.rawLayer->getDefault<%- camelize(originalPropertyName(property)) %>();
+    auto propertyValue = self.rawLayer->get<%- camelize(originalPropertyName(property)) %>();
+<% if (property["property-function"]) { -%>
+    if (propertyValue.isUndefined()) {
+        return MGLStyleValueTransformer<<%- valueTransformerArguments(property).join(', ') %>>().toDataDrivenStyleValue(self.rawLayer->getDefault<%- camelize(originalPropertyName(property)) %>());
+    }
+    return MGLStyleValueTransformer<<%- valueTransformerArguments(property).join(', ') %>>().toDataDrivenStyleValue(propertyValue);
+<% } else { -%>
 <% if (property.type == "enum") { -%>
+    if (propertyValue.isUndefined()) {
+        return MGLStyleValueTransformer<<%- mbglType(property) %>, NSValue *, <%- mbglType(property) %>, MGL<%- camelize(property.name) %>>().toEnumStyleValue(self.rawLayer->getDefault<%- camelize(originalPropertyName(property)) %>());
+    }
     return MGLStyleValueTransformer<<%- mbglType(property) %>, NSValue *, <%- mbglType(property) %>, MGL<%- camelize(property.name) %>>().toEnumStyleValue(propertyValue);
 <% } else { -%>
+    if (propertyValue.isUndefined()) {
+        return MGLStyleValueTransformer<<%- valueTransformerArguments(property).join(', ') %>>().toStyleValue(self.rawLayer->getDefault<%- camelize(originalPropertyName(property)) %>());
+    }
     return MGLStyleValueTransformer<<%- valueTransformerArguments(property).join(', ') %>>().toStyleValue(propertyValue);
 <% } -%>
+<% } -%>
 }
 
 <% if (property.original) { -%>

platform/darwin/src/MGLStyleValue.h

@@ -2,9 +2,27 @@
 #import <CoreGraphics/CoreGraphics.h>
 
 #import "MGLFoundation.h"
+#import "MGLTypes.h"
 
 NS_ASSUME_NONNULL_BEGIN
 
+// TODO: API docs
+typedef NSString *MGLStyleFunctionOption NS_STRING_ENUM;
+
+// TODO: API docs
+extern MGL_EXPORT const MGLStyleFunctionOption MGLStyleFunctionOptionInterpolationBase;
+
+// TODO: API docs
+extern MGL_EXPORT const MGLStyleFunctionOption MGLStyleFunctionOptionDefaultValue;
+
+// TODO: API docs
+typedef NS_ENUM(NSUInteger, MGLInterpolationMode) {
+    MGLInterpolationModeExponential = 0,
+    MGLInterpolationModeInterval,
+    MGLInterpolationModeCategorical,
+    MGLInterpolationModeIdentity
+};
+
 /**
  An `MGLStyleValue` object is a generic container for a style attribute value.
  The layout and paint attribute properties of `MGLStyleLayer` can be set to
@@ -41,6 +59,8 @@ MGL_EXPORT
  */
 + (instancetype)valueWithRawValue:(T)rawValue;
 
+#pragma mark Function values
+
 /**
  Creates and returns an `MGLStyleFunction` object representing a linear zoom
  level function with any number of stops.
@@ -48,7 +68,7 @@ MGL_EXPORT
  @param stops A dictionary associating zoom levels with style values.
  @return An `MGLStyleFunction` object with the given stops.
  */
-+ (instancetype)valueWithStops:(NSDictionary<NSNumber *, MGLStyleValue<T> *> *)stops;
++ (instancetype)valueWithStops:(NSDictionary<NSNumber *, MGLStyleValue<T> *> *)stops __attribute__((deprecated("Use +[MGLStyleValue valueWithInterpolationMode:cameraStops:options:]")));
 
 /**
  Creates and returns an `MGLStyleFunction` object representing a zoom level
@@ -58,7 +78,16 @@ MGL_EXPORT
  @param stops A dictionary associating zoom levels with style values.
  @return An `MGLStyleFunction` object with the given interpolation base and stops.
  */
-+ (instancetype)valueWithInterpolationBase:(CGFloat)interpolationBase stops:(NSDictionary<NSNumber *, MGLStyleValue<T> *> *)stops;
++ (instancetype)valueWithInterpolationBase:(CGFloat)interpolationBase stops:(NSDictionary<NSNumber *, MGLStyleValue<T> *> *)stops __attribute__((deprecated("Use +[MGLStyleValue valueWithInterpolationMode:cameraStops:options:]")));
+
+// TODO: API docs
++ (instancetype)valueWithInterpolationMode:(MGLInterpolationMode)interpolationMode cameraStops:(NS_DICTIONARY_OF(id, MGLStyleValue<T> *) *)stops options:(nullable NS_DICTIONARY_OF(MGLStyleFunctionOption, id) *)options;
+
+// TODO: API docs
++ (instancetype)valueWithInterpolationMode:(MGLInterpolationMode)interpolationMode sourceStops:(nullable NS_DICTIONARY_OF(id, MGLStyleValue<T> *) *)stops attributeName:(NSString *)attributeName options:(nullable NS_DICTIONARY_OF(MGLStyleFunctionOption, id) *)options;
+
+// TODO: API docs
++ (instancetype)valueWithInterpolationMode:(MGLInterpolationMode)interpolationMode compositeStops:(NS_DICTIONARY_OF(id, NS_DICTIONARY_OF(id, MGLStyleValue<T> *) *) *)stops attributeName:(NSString *)attributeName options:(nullable NS_DICTIONARY_OF(MGLStyleFunctionOption, id) *)options;
 
 @end
 
@@ -106,75 +135,76 @@ MGL_EXPORT
 
 @end
 
-/**
- An `MGLStyleFunction` is a value function defining a style value that changes
- as the zoom level changes. The layout and paint attribute properties of an
- `MGLStyleLayer` object can be set to `MGLStyleFunction` objects. Use a zoom
- level function to create the illusion of depth and control data density.
-
- The `MGLStyleFunction` class takes a generic parameter `T` that indicates the
- Foundation class being wrapped by this class.
- */
 MGL_EXPORT
-@interface MGLStyleFunction<T> : MGLStyleValue<T>
+@interface MGLCameraStyleFunction<T> : MGLStyleValue<T>
 
-#pragma mark Creating a Style Function
+// TODO: API docs
++ (instancetype)functionWithInterpolationMode:(MGLInterpolationMode)interpolationMode stops:(NS_DICTIONARY_OF(id, MGLStyleValue<T> *) *)stops options:(nullable NS_DICTIONARY_OF(MGLStyleFunctionOption, id) *)options;
 
-/**
- Creates and returns an `MGLStyleFunction` object representing a linear zoom
- level function with any number of stops.
+// TODO: API docs
+- (instancetype)initWithInterpolationMode:(MGLInterpolationMode)interpolationMode stops:(NS_DICTIONARY_OF(id, MGLStyleValue<T> *) *)stops options:(nullable NS_DICTIONARY_OF(MGLStyleFunctionOption, id) *)options NS_DESIGNATED_INITIALIZER;
 
- @param stops A dictionary associating zoom levels with style values.
- @return An `MGLStyleFunction` object with the given stops.
- */
-+ (instancetype)functionWithStops:(NSDictionary<NSNumber *, MGLStyleValue<T> *> *)stops;
+// TODO: API docs
+@property (nonatomic) MGLInterpolationMode interpolationMode;
 
-/**
- Creates and returns an `MGLStyleFunction` object representing a zoom level
- function with an exponential interpolation base and any number of stops.
+// TODO: API docs
+@property (nonatomic, copy) NS_DICTIONARY_OF(id, MGLStyleValue<T> *) *stops;
 
- @param interpolationBase The exponential base of the interpolation curve.
- @param stops A dictionary associating zoom levels with style values.
- @return An `MGLStyleFunction` object with the given interpolation base and stops.
- */
-+ (instancetype)functionWithInterpolationBase:(CGFloat)interpolationBase stops:(NSDictionary<NSNumber *, MGLStyleValue<T> *> *)stops;
-
-#pragma mark Initializing a Style Function
-
-/**
- Returns an `MGLStyleFunction` object representing a zoom level function with an
- exponential interpolation base and any number of stops.
-
- @param interpolationBase The exponential base of the interpolation curve.
- @param stops A dictionary associating zoom levels with style values.
- @return An `MGLStyleFunction` object with the given interpolation base and stops.
- */
-- (instancetype)initWithInterpolationBase:(CGFloat)interpolationBase stops:(NSDictionary<NSNumber *, MGLStyleValue<T> *> *)stops NS_DESIGNATED_INITIALIZER;
-
-#pragma mark Accessing the Parameters of a Function
-
-/**
- The exponential interpolation base of the function’s interpolation curve.
-
- The exponential interpolation base controls the rate at which the function’s output values
- increase. A value of 1 causes the function to increase linearly by zoom level.
- A higher exponential interpolation base causes the function’s output values to vary
- exponentially, increasing more rapidly towards the high end of the function’s
- range. The default value of this property is 1, for a linear curve.
- */
+// TODO: API docs
 @property (nonatomic) CGFloat interpolationBase;
 
-/**
- A dictionary associating zoom levels with style values.
+@end
 
- Each of the function’s stops is represented by one key-value pair in the
- dictionary. Each key in the dictionary is an `NSNumber` object containing a
- floating-point zoom level. Each value in the dictionary is an `MGLStyleValue`
- object containing the value of the style attribute when the map is at the
- associated zoom level. An `MGLStyleFunction` object may not be used recursively
- as a stop value.
- */
-@property (nonatomic, copy) NSDictionary<NSNumber *, MGLStyleValue<T> *> *stops;
+@compatibility_alias MGLStyleFunction MGLCameraStyleFunction;
+
+MGL_EXPORT
+@interface MGLSourceStyleFunction<T> : MGLStyleValue<T>
+
+// TODO: API docs
++ (instancetype)functionWithInterpolationMode:(MGLInterpolationMode)interpolationMode stops:(nullable NS_DICTIONARY_OF(id, MGLStyleValue<T> *) *)stops attributeName:(NSString *)attributeName options:(nullable NS_DICTIONARY_OF(MGLStyleFunctionOption, id) *)options;
+
+// TODO: API docs
+- (instancetype)initWithInterpolationMode:(MGLInterpolationMode)interpolationMode stops:(nullable NS_DICTIONARY_OF(id, MGLStyleValue<T> *) *)stops attributeName:(NSString *)attributeName options:(nullable NS_DICTIONARY_OF(MGLStyleFunctionOption, id) *)options NS_DESIGNATED_INITIALIZER;
+
+// TODO: API docs
+@property (nonatomic) MGLInterpolationMode interpolationMode;
+
+// TODO: API docs
+@property (nonatomic, copy) NSString *attributeName;
+
+// TODO: API docs
+@property (nonatomic, copy, nullable) NS_DICTIONARY_OF(id, MGLStyleValue<T> *) *stops;
+
+// TODO: API docs
+@property (nonatomic, nullable) MGLStyleValue<T> *defaultValue;
+
+// TODO: API docs
+@property (nonatomic) CGFloat interpolationBase;
+
+@end
+
+MGL_EXPORT
+@interface MGLCompositeStyleFunction<T> : MGLStyleValue<T>
+
+// TODO: API docs
++ (instancetype)functionWithInterpolationMode:(MGLInterpolationMode)interpolationMode stops:(NS_DICTIONARY_OF(id, NS_DICTIONARY_OF(id, MGLStyleValue<T> *) *) *)stops attributeName:(NSString *)attributeName options:(nullable NS_DICTIONARY_OF(MGLStyleFunctionOption, id) *)options;
+
+- (instancetype)initWithInterpolationMode:(MGLInterpolationMode)interpolationMode stops:(NS_DICTIONARY_OF(id, NS_DICTIONARY_OF(id, MGLStyleValue<T> *) *) *)stops attributeName:(NSString *)attributeName options:(nullable NS_DICTIONARY_OF(MGLStyleFunctionOption, id) *)options NS_DESIGNATED_INITIALIZER;
+
+// TODO: API docs
+@property (nonatomic) MGLInterpolationMode interpolationMode;
+
+// TODO: API docs
+@property (nonatomic, copy) NSString *attributeName;
+
+// TODO: API docs
+@property (nonatomic, copy) NS_DICTIONARY_OF(id, NS_DICTIONARY_OF(id, MGLStyleValue<T> *) *) *stops;
+
+// TODO: API docs
+@property (nonatomic, nullable) MGLStyleValue<T> *defaultValue;
+
+// TODO: API docs
+@property (nonatomic) CGFloat interpolationBase;
 
 @end
 

platform/darwin/src/MGLStyleValue.mm

@@ -1,5 +1,8 @@
 #import "MGLStyleValue_Private.h"
 
+const MGLStyleFunctionOption MGLStyleFunctionOptionInterpolationBase = @"MGLStyleFunctionOptionInterpolationBase";
+const MGLStyleFunctionOption MGLStyleFunctionOptionDefaultValue = @"MGLStyleFunctionOptionDefaultValue";
+
 @implementation MGLStyleValue
 
 + (instancetype)valueWithRawValue:(id)rawValue {
@@ -7,11 +10,23 @@
 }
 
 + (instancetype)valueWithInterpolationBase:(CGFloat)interpolationBase stops:(NSDictionary *)stops {
-    return [MGLStyleFunction functionWithInterpolationBase:interpolationBase stops:stops];
+    return [MGLCameraStyleFunction functionWithInterpolationMode:MGLInterpolationModeExponential stops:stops options:@{MGLStyleFunctionOptionInterpolationBase: @(interpolationBase)}];
 }
 
 + (instancetype)valueWithStops:(NSDictionary *)stops {
-    return [MGLStyleFunction functionWithStops:stops];
+    return [MGLCameraStyleFunction functionWithInterpolationMode:MGLInterpolationModeExponential stops:stops options:nil];
+}
+
++ (instancetype)valueWithInterpolationMode:(MGLInterpolationMode)interpolationMode cameraStops:(NSDictionary *)stops options:(NSDictionary *)options {
+    return [MGLCameraStyleFunction functionWithInterpolationMode:interpolationMode stops:stops options:options];
+}
+
++ (instancetype)valueWithInterpolationMode:(MGLInterpolationMode)interpolationMode sourceStops:(NSDictionary *)stops attributeName:(NSString *)attributeName options:(NSDictionary *)options {
+    return [MGLSourceStyleFunction functionWithInterpolationMode:interpolationMode stops:stops attributeName:attributeName options:options];
+}
+
++ (instancetype)valueWithInterpolationMode:(MGLInterpolationMode)interpolationMode compositeStops:(NSDictionary *)stops attributeName:(NSString *)attributeName options:(NSDictionary *)options {
+    return [MGLCompositeStyleFunction functionWithInterpolationMode:interpolationMode stops:stops attributeName:attributeName options:options];
 }
 
 @end
@@ -47,46 +62,203 @@
 
 @end
 
-@implementation MGLStyleFunction
+@implementation MGLCameraStyleFunction
 
-+ (instancetype)functionWithInterpolationBase:(CGFloat)interpolationBase stops:(NSDictionary *)stops {
-    return [[self alloc] initWithInterpolationBase:interpolationBase stops:stops];
-}
+@synthesize interpolationMode = _interpolationMode;
 
-+ (instancetype)functionWithStops:(NSDictionary *)stops {
-    return [[self alloc] initWithInterpolationBase:1 stops:stops];
++ (instancetype)functionWithInterpolationMode:(MGLInterpolationMode)interpolationMode stops:(NSDictionary *)stops options:(NSDictionary *)options {
+    return [[self alloc] initWithInterpolationMode:interpolationMode stops:stops options:options];
 }
 
 - (instancetype)init {
-    return [self initWithInterpolationBase:1 stops:@{}];
+    return [self initWithInterpolationMode:MGLInterpolationModeExponential stops:@{} options:nil];
 }
 
-- (instancetype)initWithInterpolationBase:(CGFloat)interpolationBase stops:(NSDictionary *)stops {
-    if (self = [super init]) {
-        if (!stops.count)
-        {
-            [NSException raise:NSInvalidArgumentException format:@"%@ requires at least one stop.", self];
-        }
-        _interpolationBase = interpolationBase;
+- (instancetype)initWithInterpolationMode:(MGLInterpolationMode)interpolationMode stops:(NSDictionary *)stops options:(NSDictionary *)options {
+    if (![stops count]) {
+        [NSException raise:NSInvalidArgumentException
+                    format:@"Camera functions must have at least one stop."];
+        return {};
+    }
+
+    if (self == [super init]) {
+        _interpolationMode = interpolationMode;
         _stops = stops;
+        _interpolationBase = 1.0;
+
+        if ([options.allKeys containsObject:MGLStyleFunctionOptionInterpolationBase]) {
+            if ([options[MGLStyleFunctionOptionInterpolationBase] isKindOfClass:[NSNumber class]]) {
+                NSNumber *value = (NSNumber *)options[MGLStyleFunctionOptionInterpolationBase];
+                _interpolationBase = [value floatValue];
+            } else {
+                [NSException raise:NSInvalidArgumentException format:@"Interpolation base must be an NSNumber that represents a CGFloat."];
+            }
+        }
     }
     return self;
 }
 
 - (NSString *)description {
-    return [NSString stringWithFormat:@"<%@: %p, interpolationBase = %f; stops = %@>",
+    return [NSString stringWithFormat:@"<%@: %p, \
+            interpolationMode = %lu, \
+            stops = %@, \
+            interpolationBase = %f>",
             NSStringFromClass([self class]), (void *)self,
-            self.interpolationBase,
-            self.stops];
+            (unsigned long)self.interpolationMode,
+            self.stops,
+            self.interpolationBase];
 }
 
-- (BOOL)isEqual:(MGLStyleFunction *)other {
-    return ([other isKindOfClass:[self class]] && other.interpolationBase == self.interpolationBase
-            && [other.stops isEqualToDictionary:self.stops]);
+- (BOOL)isEqual:(MGLCameraStyleFunction *)other {
+    return ([other isKindOfClass:[self class]]
+            && other.interpolationMode == self.interpolationMode
+            && [other.stops isEqualToDictionary:self.stops]
+            && other.interpolationBase == self.interpolationBase);
 }
 
 - (NSUInteger)hash {
-    return self.interpolationBase + self.stops.hash;
+    return  self.interpolationMode + self.stops.hash + self.interpolationBase;
+}
+
+@end
+
+@implementation MGLSourceStyleFunction
+
+@synthesize interpolationMode = _interpolationMode;
+
++ (instancetype)functionWithInterpolationMode:(MGLInterpolationMode)interpolationMode stops:(NSDictionary *)stops attributeName:(NSString *)attributeName options:(NSDictionary *)options {
+    return [[self alloc] initWithInterpolationMode:interpolationMode stops:stops attributeName:attributeName options:options];
+}
+
+- (instancetype)init {
+    return [self initWithInterpolationMode:MGLInterpolationModeExponential stops:nil attributeName:@"" options:nil];
+}
+
+- (instancetype)initWithInterpolationMode:(MGLInterpolationMode)interpolationMode stops:(NSDictionary *)stops attributeName:(NSString *)attributeName options:(NSDictionary *)options {
+    if (self == [super init]) {
+        _interpolationMode = interpolationMode;
+        _stops = stops;
+        _attributeName = attributeName;
+        _interpolationBase = 1.0;
+
+        if ([options.allKeys containsObject:MGLStyleFunctionOptionDefaultValue]) {
+            if ([options[MGLStyleFunctionOptionDefaultValue] isKindOfClass:[MGLStyleValue class]]) {
+                MGLStyleValue *value = (MGLStyleValue *)options[MGLStyleFunctionOptionDefaultValue];
+                _defaultValue = value;
+            } else {
+                [NSException raise:NSInvalidArgumentException format:@"Default value must be an MGLStyleValue"];
+            }
+        }
+
+        if ([options.allKeys containsObject:MGLStyleFunctionOptionInterpolationBase]) {
+            if ([options[MGLStyleFunctionOptionInterpolationBase] isKindOfClass:[NSNumber class]]) {
+                NSNumber *value = (NSNumber *)options[MGLStyleFunctionOptionInterpolationBase];
+                _interpolationBase = [value floatValue];
+            } else {
+                [NSException raise:NSInvalidArgumentException format:@"Interpolation base must be an NSNumber that represents a CGFloat."];
+            }
+        }
+    }
+    return self;
+}
+
+- (NSString *)description {
+    return [NSString stringWithFormat:@"<%@: %p, \
+            interpolationMode = %lu, \
+            stops = %@, \
+            attributeName = %@, \
+            defaultValue = %@, \
+            interpolationBase = %f>",
+            NSStringFromClass([self class]),
+            (void *)self,
+            (unsigned long)self.interpolationMode,
+            self.stops,
+            self.attributeName,
+            self.defaultValue,
+            self.interpolationBase];
+}
+
+- (BOOL)isEqual:(MGLSourceStyleFunction *)other {
+    return ([other isKindOfClass:[self class]]
+            && other.interpolationMode == self.interpolationMode
+            && ((self.stops && [other.stops isEqualToDictionary:self.stops]) || (!self.stops && !other.stops))
+            && [other.attributeName isEqual:self.attributeName]
+            && ((self.defaultValue && [other.defaultValue isEqual:self.defaultValue]) || (!self.defaultValue && !other.defaultValue))
+            && other.interpolationBase == self.interpolationBase);
+}
+
+- (NSUInteger)hash {
+    return self.interpolationMode + self.stops.hash + self.attributeName.hash + self.defaultValue.hash + self.interpolationBase;
+}
+
+@end
+
+@implementation MGLCompositeStyleFunction
+
+@synthesize interpolationMode = _interpolationMode;
+
++ (instancetype)functionWithInterpolationMode:(MGLInterpolationMode)interpolationMode stops:(NSDictionary *)stops attributeName:(NSString *)attributeName options:(NSDictionary *)options {
+    return [[self alloc] initWithInterpolationMode:interpolationMode stops:stops attributeName:attributeName options:options];
+}
+
+- (instancetype)init {
+    return [self initWithInterpolationMode:MGLInterpolationModeExponential stops:@{} attributeName:@"" options:nil];
+}
+
+- (instancetype)initWithInterpolationMode:(MGLInterpolationMode)interpolationMode stops:(NSDictionary *)stops attributeName:(NSString *)attributeName options:(NSDictionary *)options {
+    if (self == [super init]) {
+        _interpolationMode = interpolationMode;
+        _stops = stops;
+        _attributeName = attributeName;
+        _interpolationBase = 1.0;
+
+        if ([options.allKeys containsObject:MGLStyleFunctionOptionDefaultValue]) {
+            if ([options[MGLStyleFunctionOptionDefaultValue] isKindOfClass:[MGLStyleValue class]]) {
+                MGLStyleValue *value = (MGLStyleValue *)options[MGLStyleFunctionOptionDefaultValue];
+                _defaultValue = value;
+            } else {
+                [NSException raise:NSInvalidArgumentException format:@"Default value must be an MGLStyleValue"];
+            }
+        }
+
+        if ([options.allKeys containsObject:MGLStyleFunctionOptionInterpolationBase]) {
+            if ([options[MGLStyleFunctionOptionInterpolationBase] isKindOfClass:[NSNumber class]]) {
+                NSNumber *value = (NSNumber *)options[MGLStyleFunctionOptionInterpolationBase];
+                _interpolationBase = [value floatValue];
+            } else {
+                [NSException raise:NSInvalidArgumentException format:@"Interpolation base must be an NSNumber that represents a CGFloat."];
+            }
+        }
+    }
+    return self;
+}
+
+- (NSString *)description {
+    return [NSString stringWithFormat:@"<%@: %p, \
+            interpolationMode = %lu, \
+            stops = %@, \
+            attributeName = %@, \
+            defaultValue = %@, \
+            interpolationBase = %f>",
+            NSStringFromClass([self class]), (void *)self,
+            (unsigned long)self.interpolationMode,
+            self.stops,
+            self.attributeName,
+            self.defaultValue,
+            self.interpolationBase];
+}
+
+- (BOOL)isEqual:(MGLCompositeStyleFunction *)other {
+    return ([other isKindOfClass:[self class]]
+            && other.interpolationMode == self.interpolationMode
+            && [other.stops isEqualToDictionary:self.stops]
+            && [other.attributeName isEqual:self.attributeName]
+            && ((self.defaultValue && [other.defaultValue isEqual:self.defaultValue]) || (!self.defaultValue && !other.defaultValue))
+            && other.interpolationBase == self.interpolationBase);
+}
+
+- (NSUInteger)hash {
+    return  self.interpolationMode + self.stops.hash + self.attributeName.hash + self.interpolationBase;
 }
 
 @end

platform/darwin/src/MGLStyleValue_Private.h

@@ -4,64 +4,62 @@
 
 #import "NSValue+MGLStyleAttributeAdditions.h"
 #import "MGLTypes.h"
+
 #import <mbgl/util/enum.hpp>
 
+#include <mbgl/style/data_driven_property_value.hpp>
+
+#include <mbgl/util/interpolate.hpp>
+
 #if TARGET_OS_IPHONE
     #import "UIColor+MGLAdditions.h"
 #else
     #import "NSColor+MGLAdditions.h"
 #endif
 
-#include <array>
-
 template <typename MBGLType, typename ObjCType, typename MBGLElement = MBGLType, typename ObjCEnum = ObjCType>
 class MGLStyleValueTransformer {
 public:
 
+    // Convert an mbgl property value into an mgl style value
     MGLStyleValue<ObjCType> *toStyleValue(const mbgl::style::PropertyValue<MBGLType> &mbglValue) {
-        if (mbglValue.isConstant()) {
-            return toStyleConstantValue(mbglValue.asConstant());
-        } else if (mbglValue.isFunction()) {
-            return toStyleFunction(mbglValue.asFunction());
-        } else {
-            return nil;
-        }
+        PropertyValueEvaluator evaluator;
+        return mbglValue.evaluate(evaluator);
     }
 
+    // Convert an mbgl data driven property value into an mgl style value
+    MGLStyleValue<ObjCType> *toDataDrivenStyleValue(const mbgl::style::DataDrivenPropertyValue<MBGLType> &mbglValue) {
+        PropertyValueEvaluator evaluator;
+        return mbglValue.evaluate(evaluator);
+    }
+
+    // Convert an mbgl property value containing an enum into an mgl style value
     template <typename MBGLEnum = MBGLType,
               class = typename std::enable_if<std::is_enum<MBGLEnum>::value>::type,
               typename MGLEnum = ObjCEnum,
               class = typename std::enable_if<std::is_enum<MGLEnum>::value>::type>
     MGLStyleValue<ObjCType> *toEnumStyleValue(const mbgl::style::PropertyValue<MBGLEnum> &mbglValue) {
-        if (mbglValue.isConstant()) {
-            return toEnumStyleConstantValue<>(mbglValue.asConstant());
-        } else if (mbglValue.isFunction()) {
-            const auto &mbglStops = mbglValue.asFunction().getStops();
-            NSMutableDictionary *stops = [NSMutableDictionary dictionaryWithCapacity:mbglStops.size()];
-            for (const auto &mbglStop : mbglStops) {
-                stops[@(mbglStop.first)] = toEnumStyleConstantValue<>(mbglStop.second);
-            }
-            return [MGLStyleFunction<NSValue *> functionWithInterpolationBase:mbglValue.asFunction().getBase() stops:stops];
-        } else {
-            return nil;
-        }
+        EnumPropertyValueEvaluator<MBGLEnum, ObjCEnum> evaluator;
+        return mbglValue.evaluate(evaluator);
     }
 
+    // Convert an mgl style value into a non interpolatable (camera with interval stops) mbgl property value
     mbgl::style::PropertyValue<MBGLType> toPropertyValue(MGLStyleValue<ObjCType> *value) {
+        if ([value isKindOfClass:[MGLSourceStyleFunction class]] || [value isKindOfClass:[MGLCompositeStyleFunction class]]) {
+            [NSException raise:NSInvalidArgumentException
+                        format:@"This property can only be set to camera functions. Use +[MGLStyleValue cameraFunctionValueWithinterpolationMode:stops:options:] instead."];
+            return {};
+        }
+
         if ([value isKindOfClass:[MGLStyleConstantValue class]]) {
-            MBGLType mbglValue;
-            getMBGLValue([(MGLStyleConstantValue<ObjCType> *)value rawValue], mbglValue);
-            return mbglValue;
-        } else if ([value isKindOfClass:[MGLStyleFunction class]]) {
-            MGLStyleFunction<ObjCType> *function = (MGLStyleFunction<ObjCType> *)value;
-            __block std::vector<std::pair<float, MBGLType>> mbglStops;
-            [function.stops enumerateKeysAndObjectsUsingBlock:^(NSNumber * _Nonnull zoomKey, MGLStyleValue<ObjCType> * _Nonnull stopValue, BOOL * _Nonnull stop) {
-                NSCAssert([stopValue isKindOfClass:[MGLStyleValue class]], @"Stops should be MGLStyleValues");
-                auto mbglStopValue = toPropertyValue(stopValue);
-                NSCAssert(mbglStopValue.isConstant(), @"Stops must be constant");
-                mbglStops.emplace_back(zoomKey.floatValue, mbglStopValue.asConstant());
-            }];
-            return mbgl::style::Function<MBGLType>({{mbglStops}}, function.interpolationBase);
+            return toMBGLConstantValue((MGLStyleConstantValue<ObjCType> *)value);
+        } else if ([value isKindOfClass:[MGLCameraStyleFunction class]]) {
+            MGLCameraStyleFunction<ObjCType> *cameraStyleFunction = (MGLCameraStyleFunction<ObjCType> *)value;
+            // Intentionally ignore the stop type set by the developer becuase non interpolatable property values
+            // can only have interval stops. This also allows for backwards compatiblity when the developer uses
+            // a deprecated MGLStyleValue method (that used to create an MGLStyleFunction) to create a function
+            // for properties that are piecewise-constant (i.e. enum, bool, string)
+            return toMBGLIntervalCameraFunction(cameraStyleFunction);
         } else if (value) {
             [NSException raise:@"MGLAbstractClassException" format:
              @"The style value %@ cannot be applied to the style. "
@@ -73,25 +71,224 @@ public:
         }
     }
 
+    // Convert an mgl style value into a non interpolatable (camera with exponential or interval stops) mbgl property value
+    mbgl::style::PropertyValue<MBGLType> toInterpolatablePropertyValue(MGLStyleValue<ObjCType> *value) {
+        if ([value isKindOfClass:[MGLSourceStyleFunction class]] || [value isKindOfClass:[MGLCompositeStyleFunction class]]) {
+            [NSException raise:NSInvalidArgumentException
+                        format:@"This property can only be set to camera functions. Use +[MGLStyleValue cameraFunctionValueWithinterpolationMode:stops:options:] instead."];
+            return {};
+        }
+
+        if ([value isKindOfClass:[MGLStyleConstantValue class]]) {
+            return toMBGLConstantValue((MGLStyleConstantValue<ObjCType> *)value);
+        } else if ([value isKindOfClass:[MGLCameraStyleFunction class]]) {
+            MGLCameraStyleFunction<ObjCType> *cameraStyleFunction = (MGLCameraStyleFunction<ObjCType> *)value;
+            switch (cameraStyleFunction.interpolationMode) {
+                case MGLInterpolationModeExponential:
+                    return toMBGLExponentialCameraFunction(cameraStyleFunction);
+                    break;
+                case MGLInterpolationModeInterval:
+                    return toMBGLIntervalCameraFunction(cameraStyleFunction);
+                    break;
+                default:
+                    [NSException raise:NSInvalidArgumentException
+                                format:@"A camera function must use either exponential or interval stops."];
+                    break;
+            }
+            return {};
+        } else if (value) {
+            [NSException raise:@"MGLAbstractClassException" format:
+             @"The style value %@ cannot be applied to the style. "
+             @"Make sure the style value was created as a member of a concrete subclass of MGLStyleValue.",
+             NSStringFromClass([value class])];
+            return {};
+        } else {
+            return {};
+        }
+    }
+
+    // Convert an mgl style value into a mbgl data driven property value
+    mbgl::style::DataDrivenPropertyValue<MBGLType> toDataDrivenPropertyValue(MGLStyleValue<ObjCType> *value) {
+        if ([value isKindOfClass:[MGLStyleConstantValue class]]) {
+            return toMBGLConstantValue((MGLStyleConstantValue<ObjCType> *)value);
+        } else if ([value isKindOfClass:[MGLCameraStyleFunction class]]) {
+            MGLCameraStyleFunction<ObjCType> *cameraStyleFunction = (MGLCameraStyleFunction<ObjCType> *)value;
+            switch (cameraStyleFunction.interpolationMode) {
+                case MGLInterpolationModeExponential:
+                    return toMBGLExponentialCameraFunction(cameraStyleFunction);
+                    break;
+                case MGLInterpolationModeInterval:
+                    return toMBGLIntervalCameraFunction(cameraStyleFunction);
+                    break;
+                default:
+                    [NSException raise:NSInvalidArgumentException
+                                format:@"A camera function must use either exponential or interval stops."];
+                    return {};
+            }
+        } else if ([value isKindOfClass:[MGLSourceStyleFunction class]]) {
+            MGLSourceStyleFunction<ObjCType> *sourceStyleFunction = (MGLSourceStyleFunction<ObjCType> *)value;
+            switch (sourceStyleFunction.interpolationMode) {
+                case MGLInterpolationModeExponential:
+                    return toMBGLExponentialSourceFunction(sourceStyleFunction);
+                    break;
+                case MGLInterpolationModeInterval:
+                    return toMBGLIntervalSourceFunction(sourceStyleFunction);
+                    break;
+                case MGLInterpolationModeCategorical:
+                    return toMBGLCategoricalSourceFunction(sourceStyleFunction);
+                    break;
+                case MGLInterpolationModeIdentity:
+                    return toMBGLIdentitySourceFunction(sourceStyleFunction);
+                    break;
+                default:
+                    [NSException raise:NSInvalidArgumentException
+                                format:@"A camera function must use exponential, interval, categorical, or identity stops."];
+                    return {};
+            }
+        } else if ([value isKindOfClass:[MGLCompositeStyleFunction class]]) {
+            MGLCompositeStyleFunction<ObjCType> *compositeStyleFunction = (MGLCompositeStyleFunction<ObjCType> *)value;
+            switch (compositeStyleFunction.interpolationMode) {
+                case MGLInterpolationModeExponential: {
+                    __block std::map<float, mbgl::style::ExponentialStops<MBGLType>> outerStops = {};
+                    [compositeStyleFunction.stops enumerateKeysAndObjectsUsingBlock:^(NSNumber * _Nonnull zoomKey, NSDictionary * _Nonnull stopValue, BOOL * _Nonnull stop) {
+                        std::map<float, MBGLType> stops = {};
+                        for (NSNumber *key in stopValue.allKeys) {
+                            NSCAssert([key isKindOfClass:[NSNumber class]], @"Stop keys should be NSNumbers");
+                            MGLStyleValue<ObjCType> *value = stopValue[key];
+                            NSCAssert([value isKindOfClass:[MGLStyleValue class]], @"Stops should be MGLStyleValues");
+                            auto mbglStopValue = toPropertyValue(value);
+                            NSCAssert(mbglStopValue.isConstant(), @"Stops must be constant");
+                            stops[key.floatValue] = mbglStopValue.asConstant();
+                        }
+                        mbgl::style::ExponentialStops<MBGLType> innerStops = {stops, (float)compositeStyleFunction.interpolationBase};
+                        outerStops[zoomKey.floatValue] = innerStops;
+                    }];
+                    mbgl::style::CompositeFunction<MBGLType> compositeFunction = {compositeStyleFunction.attributeName.UTF8String, outerStops};
+                    if (compositeStyleFunction.defaultValue) {
+                        NSCAssert([compositeStyleFunction.defaultValue isKindOfClass:[MGLStyleConstantValue class]], @"Default value must be constant");
+                        MBGLType mbglValue;
+                        id mglValue = [(MGLStyleConstantValue<ObjCType> *)compositeStyleFunction.defaultValue rawValue];
+                        getMBGLValue(mglValue, mbglValue);
+                        compositeFunction.defaultValue = mbglValue;
+                    }
+                    return compositeFunction;
+                }
+                    break;
+                case MGLInterpolationModeInterval: {
+                    __block std::map<float, mbgl::style::IntervalStops<MBGLType>> outerStops = {};
+                    [compositeStyleFunction.stops enumerateKeysAndObjectsUsingBlock:^(NSNumber * _Nonnull zoomKey, NSDictionary * _Nonnull stopValue, BOOL * _Nonnull stop) {
+                        std::map<float, MBGLType> stops = {};
+                        for (NSNumber *key in stopValue.allKeys) {
+                            NSCAssert([key isKindOfClass:[NSNumber class]], @"Stop keys should be NSNumbers");
+                            MGLStyleValue<ObjCType> *value = stopValue[key];
+                            NSCAssert([value isKindOfClass:[MGLStyleValue class]], @"Stops should be MGLStyleValues");
+                            auto mbglStopValue = toPropertyValue(value);
+                            NSCAssert(mbglStopValue.isConstant(), @"Stops must be constant");
+                            stops[key.floatValue] = mbglStopValue.asConstant();
+                        }
+                        mbgl::style::IntervalStops<MBGLType> innerStops = {stops};
+                        outerStops[zoomKey.floatValue] = innerStops;
+                    }];
+                    mbgl::style::CompositeFunction<MBGLType> compositeFunction = {compositeStyleFunction.attributeName.UTF8String, outerStops};
+                    if (compositeStyleFunction.defaultValue) {
+                        NSCAssert([compositeStyleFunction.defaultValue isKindOfClass:[MGLStyleConstantValue class]], @"Default value must be constant");
+                        MBGLType mbglValue;
+                        id mglValue = [(MGLStyleConstantValue<ObjCType> *)compositeStyleFunction.defaultValue rawValue];
+                        getMBGLValue(mglValue, mbglValue);
+                        compositeFunction.defaultValue = mbglValue;
+                    }
+                    return compositeFunction;
+                }
+                    break;
+                case MGLInterpolationModeCategorical: {
+                    __block std::map<float, mbgl::style::CategoricalStops<MBGLType>> outerStops = {};
+                    [compositeStyleFunction.stops enumerateKeysAndObjectsUsingBlock:^(NSNumber * _Nonnull zoomKey, NSDictionary * _Nonnull stopValue, BOOL * _Nonnull stop) {
+                        __block std::map<mbgl::style::CategoricalValue, MBGLType> stops = {};
+                        [stopValue enumerateKeysAndObjectsUsingBlock:^(id  _Nonnull categoryKey, MGLStyleValue<ObjCType> *  _Nonnull innerValue, BOOL * _Nonnull stop) {
+                            NSCAssert([innerValue isKindOfClass:[MGLStyleValue class]], @"Stops should be MGLStyleValues");
+                            auto mbglStopValue = toPropertyValue(innerValue);
+                            NSCAssert(mbglStopValue.isConstant(), @"Stops must be constant");
+
+                            if ([categoryKey isKindOfClass:[NSString class]]) {
+                                const std::string& convertedValueKey = [((NSString *)categoryKey) UTF8String];
+                                stops[mbgl::style::CategoricalValue(convertedValueKey)] = mbglStopValue.asConstant();
+                            } else if ([categoryKey isKindOfClass:[NSNumber class]]) {
+                                NSNumber *key = (NSNumber *)categoryKey;
+                                if ((strcmp([key objCType], @encode(char)) == 0) ||
+                                    (strcmp([key objCType], @encode(BOOL)) == 0)) {
+                                    stops[mbgl::style::CategoricalValue((bool)[key boolValue])] = mbglStopValue.asConstant();
+                                } else if (strcmp([key objCType], @encode(double)) == 0 ||
+                                           strcmp([key objCType], @encode(float)) == 0) {
+                                    NSCAssert(mbglStopValue.isConstant(), @"Categorical stop keys must be strings, booleans, or integers");
+                                } else if ([key compare:@(0)] == NSOrderedDescending ||
+                                           [key compare:@(0)] == NSOrderedSame ||
+                                           [key compare:@(0)] == NSOrderedAscending) {
+                                    stops[mbgl::style::CategoricalValue((int64_t)[key integerValue])] = mbglStopValue.asConstant();
+                                }
+                            }
+                        }];
+                        mbgl::style::CategoricalStops<MBGLType> categoricalStops = {stops};
+                        outerStops[zoomKey.floatValue] = categoricalStops;
+                    }];
+                    mbgl::style::CompositeFunction<MBGLType> compositeFunction = {compositeStyleFunction.attributeName.UTF8String, outerStops};
+                    if (compositeStyleFunction.defaultValue) {
+                        NSCAssert([compositeStyleFunction.defaultValue isKindOfClass:[MGLStyleConstantValue class]], @"Default value must be constant");
+                        MBGLType mbglValue;
+                        id mglValue = [(MGLStyleConstantValue<ObjCType> *)compositeStyleFunction.defaultValue rawValue];
+                        getMBGLValue(mglValue, mbglValue);
+                        compositeFunction.defaultValue = mbglValue;
+                    }
+                    return compositeFunction;
+                }
+                    break;
+                default:
+                    [NSException raise:NSInvalidArgumentException
+                                format:@"A composite function must use exponential, interval, or categorical stops."];
+                    return {};
+            }
+            return {};
+        } else if (value) {
+            [NSException raise:@"MGLAbstractClassException" format:
+             @"The style value %@ cannot be applied to the style. "
+             @"Make sure the style value was created as a member of a concrete subclass of MGLStyleValue.",
+             NSStringFromClass([value class])];
+            return {};
+        } else {
+            return {};
+        }
+    }
+
+    // Convert an mgl style value containing an enum into a mbgl property value containing an enum
     template <typename MBGLEnum = MBGLType,
               class = typename std::enable_if<std::is_enum<MBGLEnum>::value>::type,
               typename MGLEnum = ObjCEnum,
               class = typename std::enable_if<std::is_enum<MGLEnum>::value>::type>
     mbgl::style::PropertyValue<MBGLEnum> toEnumPropertyValue(MGLStyleValue<ObjCType> *value) {
+        if ([value isKindOfClass:[MGLSourceStyleFunction class]] || [value isKindOfClass:[MGLCompositeStyleFunction class]]) {
+            [NSException raise:NSInvalidArgumentException
+                        format:@"This property can only be set to camera functions. Use +[MGLStyleValue cameraFunctionValueWithinterpolationMode:stops:options:] instead."];
+            return {};
+        }
+
         if ([value isKindOfClass:[MGLStyleConstantValue class]]) {
             MBGLEnum mbglValue;
             getMBGLValue([(MGLStyleConstantValue<ObjCType> *)value rawValue], mbglValue);
             return mbglValue;
-        } else if ([value isKindOfClass:[MGLStyleFunction class]]) {
-            MGLStyleFunction<NSValue *> *function = (MGLStyleFunction<NSValue *> *)value;
-            __block std::vector<std::pair<float, MBGLEnum>> mbglStops;
-            [function.stops enumerateKeysAndObjectsUsingBlock:^(NSNumber * _Nonnull zoomKey, MGLStyleValue<NSValue *> * _Nonnull stopValue, BOOL * _Nonnull stop) {
+        } else if ([value isKindOfClass:[MGLCameraStyleFunction class]]) {
+            MGLCameraStyleFunction<NSValue *> *cameraStyleFunction = (MGLCameraStyleFunction<NSValue *> *)value;
+            __block std::map<float, MBGLType> stops = {};
+            [cameraStyleFunction.stops enumerateKeysAndObjectsUsingBlock:^(NSNumber * _Nonnull zoomKey, MGLStyleValue<NSValue *> * _Nonnull stopValue, BOOL * _Nonnull stop) {
                 NSCAssert([stopValue isKindOfClass:[MGLStyleValue class]], @"Stops should be MGLStyleValues");
                 auto mbglStopValue = toEnumPropertyValue(stopValue);
                 NSCAssert(mbglStopValue.isConstant(), @"Stops must be constant");
-                mbglStops.emplace_back(zoomKey.floatValue, mbglStopValue.asConstant());
+                stops[zoomKey.floatValue] = mbglStopValue.asConstant();
             }];
-            return mbgl::style::Function<MBGLEnum>({{mbglStops}}, function.interpolationBase);
+
+            // Enumerations can only ever use interval stops.
+            mbgl::style::IntervalStops<MBGLType> intervalStops = {stops};
+
+            mbgl::style::CameraFunction<MBGLType> cameraFunction = {intervalStops};
+            return cameraFunction;
         } else if (value) {
             [NSException raise:@"MGLAbstractClassException" format:
              @"The style value %@ cannot be applied to the style. "
@@ -103,77 +300,140 @@ public:
         }
     }
 
-private:
+private: // Private utilities for converting from mgl to mbgl values
 
-    MGLStyleConstantValue<ObjCType> *toStyleConstantValue(const MBGLType mbglValue) {
-        auto rawValue = toMGLRawStyleValue(mbglValue);
-        return [MGLStyleConstantValue<ObjCType> valueWithRawValue:rawValue];
+    MBGLType toMBGLConstantValue(MGLStyleConstantValue<ObjCType> *value) {
+        MBGLType mbglValue;
+        getMBGLValue(value.rawValue, mbglValue);
+        return mbglValue;
     }
 
-    MGLStyleFunction<ObjCType> *toStyleFunction(const mbgl::style::Function<MBGLType> &mbglFunction) {
-        const auto &mbglStops = mbglFunction.getStops();
-        NSMutableDictionary *stops = [NSMutableDictionary dictionaryWithCapacity:mbglStops.size()];
-        for (const auto &mbglStop : mbglStops) {
-            auto rawValue = toMGLRawStyleValue(mbglStop.second);
-            stops[@(mbglStop.first)] = [MGLStyleValue valueWithRawValue:rawValue];
+    mbgl::style::CameraFunction<MBGLType> toMBGLExponentialCameraFunction(MGLCameraStyleFunction<ObjCType> *cameraStyleFunction) {
+        __block std::map<float, MBGLType> stops = {};
+        [cameraStyleFunction.stops enumerateKeysAndObjectsUsingBlock:^(NSNumber * _Nonnull zoomKey, MGLStyleValue<ObjCType> * _Nonnull stopValue, BOOL * _Nonnull stop) {
+            NSCAssert([stopValue isKindOfClass:[MGLStyleValue class]], @"Stops should be MGLStyleValues");
+            auto mbglStopValue = toPropertyValue(stopValue);
+            NSCAssert(mbglStopValue.isConstant(), @"Stops must be constant");
+            stops[zoomKey.floatValue] = mbglStopValue.asConstant();
+        }];
+
+        // Camera function with Exponential stops
+        mbgl::style::ExponentialStops<MBGLType> exponentialStops = {stops, (float)cameraStyleFunction.interpolationBase};
+        mbgl::style::CameraFunction<MBGLType> cameraFunction = {exponentialStops};
+
+        return cameraFunction;
+    }
+
+    mbgl::style::CameraFunction<MBGLType> toMBGLIntervalCameraFunction(MGLCameraStyleFunction<ObjCType> *cameraStyleFunction) {
+        __block std::map<float, MBGLType> stops = {};
+        [cameraStyleFunction.stops enumerateKeysAndObjectsUsingBlock:^(NSNumber * _Nonnull zoomKey, MGLStyleValue<ObjCType> * _Nonnull stopValue, BOOL * _Nonnull stop) {
+            NSCAssert([stopValue isKindOfClass:[MGLStyleValue class]], @"Stops should be MGLStyleValues");
+            auto mbglStopValue = toPropertyValue(stopValue);
+            NSCAssert(mbglStopValue.isConstant(), @"Stops must be constant");
+            stops[zoomKey.floatValue] = mbglStopValue.asConstant();
+        }];
+
+        // Camera function with Interval stops
+        mbgl::style::IntervalStops<MBGLType> intervalStops = {stops};
+        mbgl::style::CameraFunction<MBGLType> cameraFunction = {intervalStops};
+
+        return cameraFunction;
+    }
+
+    mbgl::style::SourceFunction<MBGLType> toMBGLCategoricalSourceFunction(MGLSourceStyleFunction<ObjCType> *sourceStyleFunction) {
+        __block std::map<mbgl::style::CategoricalValue, MBGLType> stops = {};
+        [sourceStyleFunction.stops enumerateKeysAndObjectsUsingBlock:^(id categoryKey, MGLStyleValue<ObjCType> *stopValue, BOOL *stop) {
+            NSCAssert([stopValue isKindOfClass:[MGLStyleValue class]], @"Stops should be MGLStyleValues");
+            auto mbglStopValue = toPropertyValue(stopValue);
+            NSCAssert(mbglStopValue.isConstant(), @"Stops must be constant");
+
+            if ([categoryKey isKindOfClass:[NSString class]]) {
+                const std::string& convertedValueKey = [((NSString *)categoryKey) UTF8String];
+                stops[mbgl::style::CategoricalValue(convertedValueKey)] = mbglStopValue.asConstant();
+            } else if ([categoryKey isKindOfClass:[NSNumber class]]) {
+                NSNumber *key = (NSNumber *)categoryKey;
+                if ((strcmp([key objCType], @encode(char)) == 0) ||
+                    (strcmp([key objCType], @encode(BOOL)) == 0)) {
+                    stops[mbgl::style::CategoricalValue((bool)[key boolValue])] = mbglStopValue.asConstant();
+                } else if (strcmp([key objCType], @encode(double)) == 0 ||
+                           strcmp([key objCType], @encode(float)) == 0) {
+                    NSCAssert(mbglStopValue.isConstant(), @"Categorical stop keys must be strings, booleans, or integers");
+                } else if ([key compare:@(0)] == NSOrderedDescending ||
+                           [key compare:@(0)] == NSOrderedSame ||
+                           [key compare:@(0)] == NSOrderedAscending) {
+                    stops[mbgl::style::CategoricalValue((int64_t)[key integerValue])] = mbglStopValue.asConstant();
+                }
+            }
+        }];
+        mbgl::style::CategoricalStops<MBGLType> categoricalStops = {stops};
+        mbgl::style::SourceFunction<MBGLType> sourceFunction = {sourceStyleFunction.attributeName.UTF8String, categoricalStops};
+        if (sourceStyleFunction.defaultValue) {
+            NSCAssert([sourceStyleFunction.defaultValue isKindOfClass:[MGLStyleConstantValue class]], @"Default value must be constant");
+            MBGLType mbglValue;
+            id mglValue = [(MGLStyleConstantValue<ObjCType> *)sourceStyleFunction.defaultValue rawValue];
+            getMBGLValue(mglValue, mbglValue);
+            sourceFunction.defaultValue = mbglValue;
         }
-        return [MGLStyleFunction<ObjCType> functionWithInterpolationBase:mbglFunction.getBase() stops:stops];
+        return sourceFunction;
     }
 
-    template <typename MBGLEnum = MBGLType,
-              class = typename std::enable_if<std::is_enum<MBGLEnum>::value>::type,
-              typename MGLEnum = ObjCEnum,
-              class = typename std::enable_if<std::is_enum<MGLEnum>::value>::type>
-    MGLStyleConstantValue<ObjCType> *toEnumStyleConstantValue(const MBGLEnum mbglValue) {
-        auto str = mbgl::Enum<MBGLEnum>::toString(mbglValue);
-        MGLEnum mglType = *mbgl::Enum<MGLEnum>::toEnum(str);
-        return [MGLStyleConstantValue<ObjCType> valueWithRawValue:[NSValue value:&mglType withObjCType:@encode(MGLEnum)]];
-    }
-
-    NSNumber *toMGLRawStyleValue(const bool mbglStopValue) {
-        return @(mbglStopValue);
-    }
-
-    NSNumber *toMGLRawStyleValue(const float mbglStopValue) {
-        return @(mbglStopValue);
-    }
-
-    NSString *toMGLRawStyleValue(const std::string &mbglStopValue) {
-        return @(mbglStopValue.c_str());
-    }
-
-    // Offsets
-    NSValue *toMGLRawStyleValue(const std::array<float, 2> &mbglStopValue) {
-        return [NSValue mgl_valueWithOffsetArray:mbglStopValue];
-    }
-
-    // Padding
-    NSValue *toMGLRawStyleValue(const std::array<float, 4> &mbglStopValue) {
-        return [NSValue mgl_valueWithPaddingArray:mbglStopValue];
-    }
-
-    MGLColor *toMGLRawStyleValue(const mbgl::Color mbglStopValue) {
-        return [MGLColor mgl_colorWithColor:mbglStopValue];
-    }
-
-    ObjCType toMGLRawStyleValue(const std::vector<MBGLElement> &mbglStopValue) {
-        NSMutableArray *array = [NSMutableArray arrayWithCapacity:mbglStopValue.size()];
-        for (const auto &mbglElement: mbglStopValue) {
-            [array addObject:toMGLRawStyleValue(mbglElement)];
+    mbgl::style::SourceFunction<MBGLType> toMBGLExponentialSourceFunction(MGLSourceStyleFunction<ObjCType> *sourceStyleFunction) {
+        __block std::map<float, MBGLType> stops = {};
+        [sourceStyleFunction.stops enumerateKeysAndObjectsUsingBlock:^(NSNumber * _Nonnull zoomKey, MGLStyleValue<ObjCType> * _Nonnull stopValue, BOOL * _Nonnull stop) {
+            NSCAssert([stopValue isKindOfClass:[MGLStyleValue class]], @"Stops should be MGLStyleValues");
+            auto mbglStopValue = toPropertyValue(stopValue);
+            NSCAssert(mbglStopValue.isConstant(), @"Stops must be constant");
+            stops[zoomKey.floatValue] = mbglStopValue.asConstant();
+        }];
+        mbgl::style::ExponentialStops<MBGLType> exponentialStops = {stops, (float)sourceStyleFunction.interpolationBase};
+        mbgl::style::SourceFunction<MBGLType> sourceFunction = {sourceStyleFunction.attributeName.UTF8String, exponentialStops};
+        if (sourceStyleFunction.defaultValue) {
+            NSCAssert([sourceStyleFunction.defaultValue isKindOfClass:[MGLStyleConstantValue class]], @"Default value must be constant");
+            MBGLType mbglValue;
+            id mglValue = [(MGLStyleConstantValue<ObjCType> *)sourceStyleFunction.defaultValue rawValue];
+            getMBGLValue(mglValue, mbglValue);
+            sourceFunction.defaultValue = mbglValue;
         }
-        return array;
+        return sourceFunction;
     }
 
-private:
+    mbgl::style::SourceFunction<MBGLType> toMBGLIntervalSourceFunction(MGLSourceStyleFunction<ObjCType> *sourceStyleFunction) {
+        __block std::map<float, MBGLType> stops = {};
+        [sourceStyleFunction.stops enumerateKeysAndObjectsUsingBlock:^(NSNumber * _Nonnull zoomKey, MGLStyleValue<ObjCType> * _Nonnull stopValue, BOOL * _Nonnull stop) {
+            NSCAssert([stopValue isKindOfClass:[MGLStyleValue class]], @"Stops should be MGLStyleValues");
+            auto mbglStopValue = toPropertyValue(stopValue);
+            NSCAssert(mbglStopValue.isConstant(), @"Stops must be constant");
+            stops[zoomKey.floatValue] = mbglStopValue.asConstant();
+        }];
+        mbgl::style::IntervalStops<MBGLType> intervalStops = {stops};
+        mbgl::style::SourceFunction<MBGLType> sourceFunction = {sourceStyleFunction.attributeName.UTF8String, intervalStops};
+        if (sourceStyleFunction.defaultValue) {
+            NSCAssert([sourceStyleFunction.defaultValue isKindOfClass:[MGLStyleConstantValue class]], @"Default value must be constant");
+            MBGLType mbglValue;
+            id mglValue = [(MGLStyleConstantValue<ObjCType> *)sourceStyleFunction.defaultValue rawValue];
+            getMBGLValue(mglValue, mbglValue);
+            sourceFunction.defaultValue = mbglValue;
+        }
+        return sourceFunction;
+    }
 
+    mbgl::style::SourceFunction<MBGLType> toMBGLIdentitySourceFunction(MGLSourceStyleFunction<ObjCType> *sourceStyleFunction) {
+        mbgl::style::IdentityStops<MBGLType> identityStops;
+        mbgl::style::SourceFunction<MBGLType> sourceFunction = {sourceStyleFunction.attributeName.UTF8String, identityStops};
+        return sourceFunction;
+    }
+
+    // Bool
     void getMBGLValue(NSNumber *rawValue, bool &mbglValue) {
         mbglValue = !!rawValue.boolValue;
     }
 
+    // Float
     void getMBGLValue(NSNumber *rawValue, float &mbglValue) {
         mbglValue = rawValue.floatValue;
     }
 
+    // String
     void getMBGLValue(NSString *rawValue, std::string &mbglValue) {
         mbglValue = rawValue.UTF8String;
     }
@@ -188,10 +448,12 @@ private:
         mbglValue = rawValue.mgl_paddingArrayValue;
     }
 
+    // Color
     void getMBGLValue(MGLColor *rawValue, mbgl::Color &mbglValue) {
         mbglValue = rawValue.mgl_color;
     }
 
+    // Array
     void getMBGLValue(ObjCType rawValue, std::vector<MBGLElement> &mbglValue) {
         mbglValue.reserve(rawValue.count);
         for (id obj in rawValue) {
@@ -212,4 +474,265 @@ private:
         auto str = mbgl::Enum<MGLEnum>::toString(mglEnum);
         mbglValue = *mbgl::Enum<MBGLEnum>::toEnum(str);
     }
+
+private: // Private utilities for converting from mbgl to mgl values
+
+    // Bool
+    static NSNumber *toMGLRawStyleValue(const bool mbglStopValue) {
+        return @(mbglStopValue);
+    }
+
+    // Float
+    static NSNumber *toMGLRawStyleValue(const float mbglStopValue) {
+        return @(mbglStopValue);
+    }
+
+    // Integer
+    static NSNumber *toMGLRawStyleValue(const int64_t mbglStopValue) {
+        return @(mbglStopValue);
+    }
+
+    // String
+    static NSString *toMGLRawStyleValue(const std::string &mbglStopValue) {
+        return @(mbglStopValue.c_str());
+    }
+
+    // Offsets
+    static NSValue *toMGLRawStyleValue(const std::array<float, 2> &mbglStopValue) {
+        return [NSValue mgl_valueWithOffsetArray:mbglStopValue];
+    }
+
+    // Padding
+    static NSValue *toMGLRawStyleValue(const std::array<float, 4> &mbglStopValue) {
+        return [NSValue mgl_valueWithPaddingArray:mbglStopValue];
+    }
+
+    // Color
+    static MGLColor *toMGLRawStyleValue(const mbgl::Color mbglStopValue) {
+        return [MGLColor mgl_colorWithColor:mbglStopValue];
+    }
+
+    // Array
+    static ObjCType toMGLRawStyleValue(const std::vector<MBGLElement> &mbglStopValue) {
+        NSMutableArray *array = [NSMutableArray arrayWithCapacity:mbglStopValue.size()];
+        for (const auto &mbglElement: mbglStopValue) {
+            [array addObject:toMGLRawStyleValue(mbglElement)];
+        }
+        return array;
+    }
+
+    // Enumerations
+    template <typename MBGLEnum = MBGLType, typename MGLEnum = ObjCEnum>
+    static NSValue *toMGLRawStyleValue(const MBGLEnum &value) {
+        auto str = mbgl::Enum<MBGLEnum>::toString(value);
+        MGLEnum mglType = *mbgl::Enum<MGLEnum>::toEnum(str);
+        return [NSValue value:&mglType withObjCType:@encode(MGLEnum)];
+    }
+
+    // Converts mbgl stops to an equivilent NSDictionary for mgl
+    static NSMutableDictionary *toConvertedStops(const std::map<float, MBGLType> &mbglStops) {
+        NSMutableDictionary *stops = [NSMutableDictionary dictionaryWithCapacity:mbglStops.size()];
+        for (const auto &mbglStop : mbglStops) {
+            auto rawValue = toMGLRawStyleValue(mbglStop.second);
+            stops[@(mbglStop.first)] = [MGLStyleValue valueWithRawValue:rawValue];
+        }
+        return stops;
+    }
+
+    // Converts mbgl interval stop categorical values to an equivilant object for mgl
+    class CategoricalValueVisitor {
+    public:
+        id operator()(const bool value) {
+            return toMGLRawStyleValue(value);
+        }
+
+        id operator()(const int64_t value) {
+            return toMGLRawStyleValue(value);
+        }
+
+        id operator()(const std::string value) {
+            return toMGLRawStyleValue(value);
+        }
+    };
+
+    // Converts all types of mbgl property values containing enumerations into an equivilant mgl style value
+    template <typename MBGLEnum = MBGLType, typename MGLEnum = ObjCEnum>
+    class EnumPropertyValueEvaluator {
+    public:
+        id operator()(const mbgl::style::Undefined) const {
+            return nil;
+        }
+
+        id operator()(const MBGLEnum &value) const {
+            auto str = mbgl::Enum<MBGLEnum>::toString(value);
+            MGLEnum mglType = *mbgl::Enum<MGLEnum>::toEnum(str);
+            return [MGLStyleConstantValue<ObjCType> valueWithRawValue:[NSValue value:&mglType withObjCType:@encode(MGLEnum)]];
+        }
+
+        id operator()(const mbgl::style::CameraFunction<MBGLEnum> &mbglValue) const {
+            CameraFunctionStopsVisitor visitor;
+            return apply_visitor(visitor, mbglValue.stops);
+        }
+    };
+
+    // Converts all possible mbgl camera function stops into an equivilant mgl style value
+    class CameraFunctionStopsVisitor {
+    public:
+        id operator()(const mbgl::style::ExponentialStops<MBGLType> &mbglStops) {
+            return [MGLCameraStyleFunction functionWithInterpolationMode:MGLInterpolationModeExponential
+                                                          stops:toConvertedStops(mbglStops.stops)
+                                                        options:@{MGLStyleFunctionOptionInterpolationBase: @(mbglStops.base)}];
+        }
+
+        id operator()(const mbgl::style::IntervalStops<MBGLType> &mbglStops) {
+            return [MGLCameraStyleFunction functionWithInterpolationMode:MGLInterpolationModeInterval
+                                                          stops:toConvertedStops(mbglStops.stops)
+                                                        options:nil];
+        }
+    };
+
+    // Converts a source function and all possible mbgl source function stops into an equivilant mgl style value
+    class SourceFunctionStopsVisitor {
+    public:
+        id operator()(const mbgl::style::ExponentialStops<MBGLType> &mbglStops) {
+            MGLSourceStyleFunction *sourceFunction = [MGLSourceStyleFunction functionWithInterpolationMode:MGLInterpolationModeExponential
+                                                                                            stops:toConvertedStops(mbglStops.stops)
+                                                                                    attributeName:@(mbglFunction.property.c_str())
+                                                                                          options:@{MGLStyleFunctionOptionInterpolationBase: @(mbglStops.base)}];
+            if (mbglFunction.defaultValue) {
+                sourceFunction.defaultValue = [MGLStyleValue valueWithRawValue:toMGLRawStyleValue(*mbglFunction.defaultValue)];
+            }
+            return sourceFunction;
+        }
+
+        id operator()(const mbgl::style::IntervalStops<MBGLType> &mbglStops) {
+            MGLSourceStyleFunction *sourceFunction = [MGLSourceStyleFunction functionWithInterpolationMode:MGLInterpolationModeInterval
+                                                                                            stops:toConvertedStops(mbglStops.stops)
+                                                                                    attributeName:@(mbglFunction.property.c_str())
+                                                                                          options:nil];
+            if (mbglFunction.defaultValue) {
+                sourceFunction.defaultValue = [MGLStyleValue valueWithRawValue:toMGLRawStyleValue(*mbglFunction.defaultValue)];
+            }
+            return sourceFunction;
+        }
+
+        id operator()(const mbgl::style::CategoricalStops<MBGLType> &mbglStops) {
+            NSMutableDictionary *stops = [NSMutableDictionary dictionaryWithCapacity:mbglStops.stops.size()];
+            for (const auto &mbglStop : mbglStops.stops) {
+                auto categoricalValue = mbglStop.first;
+                auto rawValue = toMGLRawStyleValue(mbglStop.second);
+                CategoricalValueVisitor categoricalValueVisitor;
+                id stopKey = apply_visitor(categoricalValueVisitor, categoricalValue);
+                stops[stopKey] = [MGLStyleValue valueWithRawValue:rawValue];
+            }
+
+            MGLSourceStyleFunction *sourceFunction = [MGLSourceStyleFunction functionWithInterpolationMode:MGLInterpolationModeCategorical
+                                                                                            stops:stops
+                                                                                    attributeName:@(mbglFunction.property.c_str())
+                                                                                          options:nil];
+            if (mbglFunction.defaultValue) {
+                sourceFunction.defaultValue = [MGLStyleValue valueWithRawValue:toMGLRawStyleValue(*mbglFunction.defaultValue)];
+            }
+            return sourceFunction;
+
+        }
+
+        id operator()(const mbgl::style::IdentityStops<MBGLType> &mbglStops) {
+            return [MGLSourceStyleFunction functionWithInterpolationMode:MGLInterpolationModeIdentity
+                                                          stops:nil
+                                                  attributeName:@(mbglFunction.property.c_str()) options:nil];
+        }
+
+        const mbgl::style::SourceFunction<MBGLType> &mbglFunction;
+    };
+
+    // Converts a composite function and all possible mbgl stops into an equivilant mgl style value
+    class CompositeFunctionStopsVisitor {
+    public:
+        id operator()(const std::map<float, mbgl::style::ExponentialStops<MBGLType>> &mbglStops) {
+            float base = 1.0f;
+            NSMutableDictionary *stops = [NSMutableDictionary dictionaryWithCapacity:mbglStops.size()];
+            for (auto const& outerStop: mbglStops) {
+                stops[@(outerStop.first)] = toConvertedStops(outerStop.second.stops);
+                base = outerStop.second.base;
+            }
+            MGLCompositeStyleFunction *compositeFunction = [MGLCompositeStyleFunction functionWithInterpolationMode:MGLInterpolationModeExponential
+                                                                                                     stops:stops
+                                                                                             attributeName:@(mbglFunction.property.c_str())
+                                                                                                   options:@{MGLStyleFunctionOptionInterpolationBase: @(base)}];
+            if (mbglFunction.defaultValue) {
+                compositeFunction.defaultValue = [MGLStyleValue valueWithRawValue:toMGLRawStyleValue(*mbglFunction.defaultValue)];
+            }
+            return compositeFunction;
+        }
+
+        id operator()(const std::map<float, mbgl::style::IntervalStops<MBGLType>> &mbglStops) {
+            NSMutableDictionary *stops = [NSMutableDictionary dictionaryWithCapacity:mbglStops.size()];
+            for (auto const& outerStop: mbglStops) {
+                stops[@(outerStop.first)] = toConvertedStops(outerStop.second.stops);
+            }
+            MGLCompositeStyleFunction *compositeFunction = [MGLCompositeStyleFunction functionWithInterpolationMode:MGLInterpolationModeInterval
+                                                                                                     stops:stops
+                                                                                             attributeName:@(mbglFunction.property.c_str())
+                                                                                                   options:nil];
+            if (mbglFunction.defaultValue) {
+                compositeFunction.defaultValue = [MGLStyleValue valueWithRawValue:toMGLRawStyleValue(*mbglFunction.defaultValue)];
+            }
+            return compositeFunction;
+        }
+
+        id operator()(const std::map<float, mbgl::style::CategoricalStops<MBGLType>> &mbglStops) {
+            NSMutableDictionary *stops = [NSMutableDictionary dictionaryWithCapacity:mbglStops.size()];
+            for (auto const& outerStop: mbglStops) {
+                    NSMutableDictionary *innerStops = [NSMutableDictionary dictionaryWithCapacity:outerStop.second.stops.size()];
+                for (const auto &mbglStop : outerStop.second.stops) {
+                    auto categoricalValue = mbglStop.first;
+                    auto rawValue = toMGLRawStyleValue(mbglStop.second);
+                    CategoricalValueVisitor categoricalValueVisitor;
+                    id stopKey = apply_visitor(categoricalValueVisitor, categoricalValue);
+                    innerStops[stopKey] = [MGLStyleValue valueWithRawValue:rawValue];
+                }
+                stops[@(outerStop.first)] = innerStops;
+            }
+
+            MGLCompositeStyleFunction *compositeFunction = [MGLCompositeStyleFunction functionWithInterpolationMode:MGLInterpolationModeCategorical
+                                                                                                     stops:stops attributeName:@(mbglFunction.property.c_str())
+                                                                                                   options:nil];
+            if (mbglFunction.defaultValue) {
+                compositeFunction.defaultValue = [MGLStyleValue valueWithRawValue:toMGLRawStyleValue(*mbglFunction.defaultValue)];
+            }
+            return compositeFunction;
+        }
+
+        const mbgl::style::CompositeFunction<MBGLType> &mbglFunction;
+    };
+
+
+    // Converts all types of mbgl property values that don't contain enumerations into an equivilant mgl style value
+    class PropertyValueEvaluator {
+    public:
+        id operator()(const mbgl::style::Undefined) const {
+            return nil;
+        }
+
+        id operator()(const MBGLType &value) const {
+            auto rawValue = toMGLRawStyleValue(value);
+            return [MGLStyleConstantValue<ObjCType> valueWithRawValue:rawValue];
+        }
+
+        id operator()(const mbgl::style::CameraFunction<MBGLType> &mbglValue) const {
+            CameraFunctionStopsVisitor visitor;
+            return apply_visitor(visitor, mbglValue.stops);
+        }
+
+        id operator()(const mbgl::style::SourceFunction<MBGLType> &mbglValue) const {
+            SourceFunctionStopsVisitor visitor { mbglValue };
+            return apply_visitor(visitor, mbglValue.stops);
+        }
+
+        MGLCompositeStyleFunction<ObjCType> * operator()(const mbgl::style::CompositeFunction<MBGLType> &mbglValue) const {
+            CompositeFunctionStopsVisitor visitor { mbglValue };
+            return apply_visitor(visitor, mbglValue.stops);
+        }
+    };
 };

platform/darwin/src/MGLSymbolStyleLayer.h

@@ -251,7 +251,7 @@ typedef NS_ENUM(NSUInteger, MGLTextTranslationAnchor) {
 /**
  An `MGLSymbolStyleLayer` is a style layer that renders icon and text labels at
  points or along lines on the map.
-
+ 
  Use a symbol style layer to configure the visual appearance of labels for
  features in vector tiles loaded by an `MGLVectorSource` object or `MGLShape` or
  `MGLFeature` instances in an `MGLShapeSource` object.
@@ -285,14 +285,14 @@ MGL_EXPORT
 /**
  If true, the icon will be visible even if it collides with other previously
  drawn symbols.
-
+ 
  The default value of this property is an `MGLStyleValue` object containing an
  `NSNumber` object containing `NO`. Set this property to `nil` to reset it to
  the default value.
-
+ 
  This property is only applied to the style if `iconImageName` is non-`nil`.
  Otherwise, it is ignored.
-
+ 
  This attribute corresponds to the <a
  href="https://www.mapbox.com/mapbox-gl-style-spec/#layout-symbol-icon-allow-overlap"><code>icon-allow-overlap</code></a>
  layout property in the Mapbox Style Specification.
@@ -304,14 +304,14 @@ MGL_EXPORT
 
 /**
  If true, other symbols can be visible even if they collide with the icon.
-
+ 
  The default value of this property is an `MGLStyleValue` object containing an
  `NSNumber` object containing `NO`. Set this property to `nil` to reset it to
  the default value.
-
+ 
  This property is only applied to the style if `iconImageName` is non-`nil`.
  Otherwise, it is ignored.
-
+ 
  This attribute corresponds to the <a
  href="https://www.mapbox.com/mapbox-gl-style-spec/#layout-symbol-icon-ignore-placement"><code>icon-ignore-placement</code></a>
  layout property in the Mapbox Style Specification.
@@ -323,7 +323,7 @@ MGL_EXPORT
 
 /**
  A string with {tokens} replaced, referencing the data property to pull from.
-
+ 
  This attribute corresponds to the <a
  href="https://www.mapbox.com/mapbox-gl-style-spec/#layout-symbol-icon-image"><code>icon-image</code></a>
  layout property in the Mapbox Style Specification.
@@ -336,11 +336,11 @@ MGL_EXPORT
 #if TARGET_OS_IPHONE
 /**
  Offset distance of icon from its anchor.
-
+ 
  The default value of this property is an `MGLStyleValue` object containing an
  `NSValue` object containing a `CGVector` struct set to 0 rightward and 0
  downward. Set this property to `nil` to reset it to the default value.
-
+ 
  This property is only applied to the style if `iconImageName` is non-`nil`.
  Otherwise, it is ignored.
  */
@@ -348,11 +348,11 @@ MGL_EXPORT
 #else
 /**
  Offset distance of icon from its anchor.
-
+ 
  The default value of this property is an `MGLStyleValue` object containing an
  `NSValue` object containing a `CGVector` struct set to 0 rightward and 0
  upward. Set this property to `nil` to reset it to the default value.
-
+ 
  This property is only applied to the style if `iconImageName` is non-`nil`.
  Otherwise, it is ignored.
  */
@@ -362,11 +362,11 @@ MGL_EXPORT
 /**
  If true, text will display without their corresponding icons when the icon
  collides with other symbols and the text does not.
-
+ 
  The default value of this property is an `MGLStyleValue` object containing an
  `NSNumber` object containing `NO`. Set this property to `nil` to reset it to
  the default value.
-
+ 
  This property is only applied to the style if `iconImageName` is non-`nil`, and
  `text` is non-`nil`. Otherwise, it is ignored.
  */
@@ -375,13 +375,13 @@ MGL_EXPORT
 /**
  Size of the additional area around the icon bounding box used for detecting
  symbol collisions.
-
+ 
  This property is measured in points.
-
+ 
  The default value of this property is an `MGLStyleValue` object containing an
  `NSNumber` object containing the float `2`. Set this property to `nil` to reset
  it to the default value.
-
+ 
  This property is only applied to the style if `iconImageName` is non-`nil`.
  Otherwise, it is ignored.
  */
@@ -389,16 +389,16 @@ MGL_EXPORT
 
 /**
  Rotates the icon clockwise.
-
+ 
  This property is measured in degrees.
-
+ 
  The default value of this property is an `MGLStyleValue` object containing an
  `NSNumber` object containing the float `0`. Set this property to `nil` to reset
  it to the default value.
-
+ 
  This property is only applied to the style if `iconImageName` is non-`nil`.
  Otherwise, it is ignored.
-
+ 
  This attribute corresponds to the <a
  href="https://www.mapbox.com/mapbox-gl-style-spec/#layout-symbol-icon-rotate"><code>icon-rotate</code></a>
  layout property in the Mapbox Style Specification.
@@ -411,11 +411,11 @@ MGL_EXPORT
 /**
  In combination with `symbolPlacement`, determines the rotation behavior of
  icons.
-
+ 
  The default value of this property is an `MGLStyleValue` object containing an
  `NSValue` object containing `MGLIconRotationAlignmentAuto`. Set this property
  to `nil` to reset it to the default value.
-
+ 
  This property is only applied to the style if `iconImageName` is non-`nil`.
  Otherwise, it is ignored.
  */
@@ -423,14 +423,14 @@ MGL_EXPORT
 
 /**
  Scale factor for icon. 1 is original size, 3 triples the size.
-
+ 
  The default value of this property is an `MGLStyleValue` object containing an
  `NSNumber` object containing the float `1`. Set this property to `nil` to reset
  it to the default value.
-
+ 
  This property is only applied to the style if `iconImageName` is non-`nil`.
  Otherwise, it is ignored.
-
+ 
  This attribute corresponds to the <a
  href="https://www.mapbox.com/mapbox-gl-style-spec/#layout-symbol-icon-size"><code>icon-size</code></a>
  layout property in the Mapbox Style Specification.
@@ -442,11 +442,11 @@ MGL_EXPORT
 
 /**
  Scales the icon to fit around the associated text.
-
+ 
  The default value of this property is an `MGLStyleValue` object containing an
  `NSValue` object containing `MGLIconTextFitNone`. Set this property to `nil` to
  reset it to the default value.
-
+ 
  This property is only applied to the style if `iconImageName` is non-`nil`, and
  `text` is non-`nil`. Otherwise, it is ignored.
  */
@@ -455,13 +455,13 @@ MGL_EXPORT
 #if TARGET_OS_IPHONE
 /**
  Size of the additional area added to dimensions determined by `iconTextFit`.
-
+ 
  This property is measured in points.
-
+ 
  The default value of this property is an `MGLStyleValue` object containing an
  `NSValue` object containing `UIEdgeInsetsZero`. Set this property to `nil` to
  reset it to the default value.
-
+ 
  This property is only applied to the style if `iconImageName` is non-`nil`, and
  `text` is non-`nil`, and `iconTextFit` is set to an `MGLStyleValue` object
  containing an `NSValue` object containing `MGLIconTextFitBoth`,
@@ -471,13 +471,13 @@ MGL_EXPORT
 #else
 /**
  Size of the additional area added to dimensions determined by `iconTextFit`.
-
+ 
  This property is measured in points.
-
+ 
  The default value of this property is an `MGLStyleValue` object containing an
  `NSValue` object containing `NSEdgeInsetsZero`. Set this property to `nil` to
  reset it to the default value.
-
+ 
  This property is only applied to the style if `iconImageName` is non-`nil`, and
  `text` is non-`nil`, and `iconTextFit` is set to an `MGLStyleValue` object
  containing an `NSValue` object containing `MGLIconTextFitBoth`,
@@ -488,17 +488,17 @@ MGL_EXPORT
 
 /**
  If true, the icon may be flipped to prevent it from being rendered upside-down.
-
+ 
  The default value of this property is an `MGLStyleValue` object containing an
  `NSNumber` object containing `NO`. Set this property to `nil` to reset it to
  the default value.
-
+ 
  This property is only applied to the style if `iconImageName` is non-`nil`, and
  `iconRotationAlignment` is set to an `MGLStyleValue` object containing an
  `NSValue` object containing `MGLIconRotationAlignmentMap`, and
  `symbolPlacement` is set to an `MGLStyleValue` object containing an `NSValue`
  object containing `MGLSymbolPlacementLine`. Otherwise, it is ignored.
-
+ 
  This attribute corresponds to the <a
  href="https://www.mapbox.com/mapbox-gl-style-spec/#layout-symbol-icon-keep-upright"><code>icon-keep-upright</code></a>
  layout property in the Mapbox Style Specification.
@@ -511,17 +511,17 @@ MGL_EXPORT
 /**
  If true, the text may be flipped vertically to prevent it from being rendered
  upside-down.
-
+ 
  The default value of this property is an `MGLStyleValue` object containing an
  `NSNumber` object containing `YES`. Set this property to `nil` to reset it to
  the default value.
-
+ 
  This property is only applied to the style if `text` is non-`nil`, and
  `textRotationAlignment` is set to an `MGLStyleValue` object containing an
  `NSValue` object containing `MGLTextRotationAlignmentMap`, and
  `symbolPlacement` is set to an `MGLStyleValue` object containing an `NSValue`
  object containing `MGLSymbolPlacementLine`. Otherwise, it is ignored.
-
+ 
  This attribute corresponds to the <a
  href="https://www.mapbox.com/mapbox-gl-style-spec/#layout-symbol-text-keep-upright"><code>text-keep-upright</code></a>
  layout property in the Mapbox Style Specification.
@@ -533,17 +533,17 @@ MGL_EXPORT
 
 /**
  Maximum angle change between adjacent characters.
-
+ 
  This property is measured in degrees.
-
+ 
  The default value of this property is an `MGLStyleValue` object containing an
  `NSNumber` object containing the float `45`. Set this property to `nil` to
  reset it to the default value.
-
+ 
  This property is only applied to the style if `text` is non-`nil`, and
  `symbolPlacement` is set to an `MGLStyleValue` object containing an `NSValue`
  object containing `MGLSymbolPlacementLine`. Otherwise, it is ignored.
-
+ 
  This attribute corresponds to the <a
  href="https://www.mapbox.com/mapbox-gl-style-spec/#layout-symbol-text-max-angle"><code>text-max-angle</code></a>
  layout property in the Mapbox Style Specification.
@@ -555,16 +555,16 @@ MGL_EXPORT
 
 /**
  The maximum line width for text wrapping.
-
+ 
  This property is measured in ems.
-
+ 
  The default value of this property is an `MGLStyleValue` object containing an
  `NSNumber` object containing the float `10`. Set this property to `nil` to
  reset it to the default value.
-
+ 
  This property is only applied to the style if `text` is non-`nil`. Otherwise,
  it is ignored.
-
+ 
  This attribute corresponds to the <a
  href="https://www.mapbox.com/mapbox-gl-style-spec/#layout-symbol-text-max-width"><code>text-max-width</code></a>
  layout property in the Mapbox Style Specification.
@@ -579,11 +579,11 @@ MGL_EXPORT
  Recommended in layers that don't have enough padding in the vector tile to
  prevent collisions, or if it is a point symbol layer placed after a line symbol
  layer.
-
+ 
  The default value of this property is an `MGLStyleValue` object containing an
  `NSNumber` object containing `NO`. Set this property to `nil` to reset it to
  the default value.
-
+ 
  This attribute corresponds to the <a
  href="https://www.mapbox.com/mapbox-gl-style-spec/#layout-symbol-symbol-avoid-edges"><code>symbol-avoid-edges</code></a>
  layout property in the Mapbox Style Specification.
@@ -595,7 +595,7 @@ MGL_EXPORT
 
 /**
  Label placement relative to its geometry.
-
+ 
  The default value of this property is an `MGLStyleValue` object containing an
  `NSValue` object containing `MGLSymbolPlacementPoint`. Set this property to
  `nil` to reset it to the default value.
@@ -604,13 +604,13 @@ MGL_EXPORT
 
 /**
  Distance between two symbol anchors.
-
+ 
  This property is measured in points.
-
+ 
  The default value of this property is an `MGLStyleValue` object containing an
  `NSNumber` object containing the float `250`. Set this property to `nil` to
  reset it to the default value.
-
+ 
  This property is only applied to the style if `symbolPlacement` is set to an
  `MGLStyleValue` object containing an `NSValue` object containing
  `MGLSymbolPlacementLine`. Otherwise, it is ignored.
@@ -620,10 +620,10 @@ MGL_EXPORT
 /**
  Value to use for a text label. Feature properties are specified using tokens
  like {field_name}.
-
+ 
  The default value of this property is an `MGLStyleValue` object containing the
  empty string. Set this property to `nil` to reset it to the default value.
-
+ 
  This attribute corresponds to the <a
  href="https://www.mapbox.com/mapbox-gl-style-spec/#layout-symbol-text-field"><code>text-field</code></a>
  layout property in the Mapbox Style Specification.
@@ -636,14 +636,14 @@ MGL_EXPORT
 /**
  If true, the text will be visible even if it collides with other previously
  drawn symbols.
-
+ 
  The default value of this property is an `MGLStyleValue` object containing an
  `NSNumber` object containing `NO`. Set this property to `nil` to reset it to
  the default value.
-
+ 
  This property is only applied to the style if `text` is non-`nil`. Otherwise,
  it is ignored.
-
+ 
  This attribute corresponds to the <a
  href="https://www.mapbox.com/mapbox-gl-style-spec/#layout-symbol-text-allow-overlap"><code>text-allow-overlap</code></a>
  layout property in the Mapbox Style Specification.
@@ -655,11 +655,11 @@ MGL_EXPORT
 
 /**
  Part of the text placed closest to the anchor.
-
+ 
  The default value of this property is an `MGLStyleValue` object containing an
  `NSValue` object containing `MGLTextAnchorCenter`. Set this property to `nil`
  to reset it to the default value.
-
+ 
  This property is only applied to the style if `text` is non-`nil`. Otherwise,
  it is ignored.
  */
@@ -667,24 +667,24 @@ MGL_EXPORT
 
 /**
  An array of font face names used to display the text.
-
+ 
  Each font name must be included in the `{fontstack}` portion of the JSON
  stylesheet’s <a
  href="https://www.mapbox.com/mapbox-gl-style-spec/#glyphs"><code>glyphs</code></a>
  property. You can register a custom font when designing the style in Mapbox
  Studio. Fonts installed on the system are not used.
-
+ 
  The first font named in the array is applied to the text. For each character in
  the text, if the first font lacks a glyph for the character, the next font is
  applied as a fallback, and so on.
-
+ 
  The default value of this property is an `MGLStyleValue` object containing the
  array `Open Sans Regular`, `Arial Unicode MS Regular`. Set this property to
  `nil` to reset it to the default value.
-
+ 
  This property is only applied to the style if `text` is non-`nil`. Otherwise,
  it is ignored.
-
+ 
  This attribute corresponds to the <a
  href="https://www.mapbox.com/mapbox-gl-style-spec/#layout-symbol-text-font"><code>text-font</code></a>
  layout property in the Mapbox Style Specification.
@@ -696,16 +696,16 @@ MGL_EXPORT
 
 /**
  Font size.
-
+ 
  This property is measured in points.
-
+ 
  The default value of this property is an `MGLStyleValue` object containing an
  `NSNumber` object containing the float `16`. Set this property to `nil` to
  reset it to the default value.
-
+ 
  This property is only applied to the style if `text` is non-`nil`. Otherwise,
  it is ignored.
-
+ 
  This attribute corresponds to the <a
  href="https://www.mapbox.com/mapbox-gl-style-spec/#layout-symbol-text-size"><code>text-size</code></a>
  layout property in the Mapbox Style Specification.
@@ -717,14 +717,14 @@ MGL_EXPORT
 
 /**
  If true, other symbols can be visible even if they collide with the text.
-
+ 
  The default value of this property is an `MGLStyleValue` object containing an
  `NSNumber` object containing `NO`. Set this property to `nil` to reset it to
  the default value.
-
+ 
  This property is only applied to the style if `text` is non-`nil`. Otherwise,
  it is ignored.
-
+ 
  This attribute corresponds to the <a
  href="https://www.mapbox.com/mapbox-gl-style-spec/#layout-symbol-text-ignore-placement"><code>text-ignore-placement</code></a>
  layout property in the Mapbox Style Specification.
@@ -736,14 +736,14 @@ MGL_EXPORT
 
 /**
  Text justification options.
-
+ 
  The default value of this property is an `MGLStyleValue` object containing an
  `NSValue` object containing `MGLTextJustificationCenter`. Set this property to
  `nil` to reset it to the default value.
-
+ 
  This property is only applied to the style if `text` is non-`nil`. Otherwise,
  it is ignored.
-
+ 
  This attribute corresponds to the <a
  href="https://www.mapbox.com/mapbox-gl-style-spec/#layout-symbol-text-justify"><code>text-justify</code></a>
  layout property in the Mapbox Style Specification.
@@ -755,13 +755,13 @@ MGL_EXPORT
 
 /**
  Text tracking amount.
-
+ 
  This property is measured in ems.
-
+ 
  The default value of this property is an `MGLStyleValue` object containing an
  `NSNumber` object containing the float `0`. Set this property to `nil` to reset
  it to the default value.
-
+ 
  This property is only applied to the style if `text` is non-`nil`. Otherwise,
  it is ignored.
  */
@@ -769,13 +769,13 @@ MGL_EXPORT
 
 /**
  Text leading value for multi-line text.
-
+ 
  This property is measured in ems.
-
+ 
  The default value of this property is an `MGLStyleValue` object containing an
  `NSNumber` object containing the float `1.2`. Set this property to `nil` to
  reset it to the default value.
-
+ 
  This property is only applied to the style if `text` is non-`nil`. Otherwise,
  it is ignored.
  */
@@ -784,13 +784,13 @@ MGL_EXPORT
 #if TARGET_OS_IPHONE
 /**
  Offset distance of text from its anchor.
-
+ 
  This property is measured in ems.
-
+ 
  The default value of this property is an `MGLStyleValue` object containing an
  `NSValue` object containing a `CGVector` struct set to 0 ems rightward and 0
  ems downward. Set this property to `nil` to reset it to the default value.
-
+ 
  This property is only applied to the style if `text` is non-`nil`. Otherwise,
  it is ignored.
  */
@@ -798,13 +798,13 @@ MGL_EXPORT
 #else
 /**
  Offset distance of text from its anchor.
-
+ 
  This property is measured in ems.
-
+ 
  The default value of this property is an `MGLStyleValue` object containing an
  `NSValue` object containing a `CGVector` struct set to 0 ems rightward and 0
  ems upward. Set this property to `nil` to reset it to the default value.
-
+ 
  This property is only applied to the style if `text` is non-`nil`. Otherwise,
  it is ignored.
  */
@@ -814,11 +814,11 @@ MGL_EXPORT
 /**
  If true, icons will display without their corresponding text when the text
  collides with other symbols and the icon does not.
-
+ 
  The default value of this property is an `MGLStyleValue` object containing an
  `NSNumber` object containing `NO`. Set this property to `nil` to reset it to
  the default value.
-
+ 
  This property is only applied to the style if `text` is non-`nil`, and
  `iconImageName` is non-`nil`. Otherwise, it is ignored.
  */
@@ -827,13 +827,13 @@ MGL_EXPORT
 /**
  Size of the additional area around the text bounding box used for detecting
  symbol collisions.
-
+ 
  This property is measured in points.
-
+ 
  The default value of this property is an `MGLStyleValue` object containing an
  `NSNumber` object containing the float `2`. Set this property to `nil` to reset
  it to the default value.
-
+ 
  This property is only applied to the style if `text` is non-`nil`. Otherwise,
  it is ignored.
  */
@@ -841,11 +841,11 @@ MGL_EXPORT
 
 /**
  Orientation of text when map is pitched.
-
+ 
  The default value of this property is an `MGLStyleValue` object containing an
  `NSValue` object containing `MGLTextPitchAlignmentAuto`. Set this property to
  `nil` to reset it to the default value.
-
+ 
  This property is only applied to the style if `text` is non-`nil`. Otherwise,
  it is ignored.
  */
@@ -853,16 +853,16 @@ MGL_EXPORT
 
 /**
  Rotates the text clockwise.
-
+ 
  This property is measured in degrees.
-
+ 
  The default value of this property is an `MGLStyleValue` object containing an
  `NSNumber` object containing the float `0`. Set this property to `nil` to reset
  it to the default value.
-
+ 
  This property is only applied to the style if `text` is non-`nil`. Otherwise,
  it is ignored.
-
+ 
  This attribute corresponds to the <a
  href="https://www.mapbox.com/mapbox-gl-style-spec/#layout-symbol-text-rotate"><code>text-rotate</code></a>
  layout property in the Mapbox Style Specification.
@@ -875,11 +875,11 @@ MGL_EXPORT
 /**
  In combination with `symbolPlacement`, determines the rotation behavior of the
  individual glyphs forming the text.
-
+ 
  The default value of this property is an `MGLStyleValue` object containing an
  `NSValue` object containing `MGLTextRotationAlignmentAuto`. Set this property
  to `nil` to reset it to the default value.
-
+ 
  This property is only applied to the style if `text` is non-`nil`. Otherwise,
  it is ignored.
  */
@@ -887,11 +887,11 @@ MGL_EXPORT
 
 /**
  Specifies how to capitalize text.
-
+ 
  The default value of this property is an `MGLStyleValue` object containing an
  `NSValue` object containing `MGLTextTransformNone`. Set this property to `nil`
  to reset it to the default value.
-
+ 
  This property is only applied to the style if `text` is non-`nil`. Otherwise,
  it is ignored.
  */
@@ -903,11 +903,11 @@ MGL_EXPORT
 /**
  The tint color to apply to the icon. The `iconImageName` property must be set
  to a template image.
-
+ 
  The default value of this property is an `MGLStyleValue` object containing
  `UIColor.blackColor`. Set this property to `nil` to reset it to the default
  value.
-
+ 
  This property is only applied to the style if `iconImageName` is non-`nil`.
  Otherwise, it is ignored.
  */
@@ -916,11 +916,11 @@ MGL_EXPORT
 /**
  The tint color to apply to the icon. The `iconImageName` property must be set
  to a template image.
-
+ 
  The default value of this property is an `MGLStyleValue` object containing
  `NSColor.blackColor`. Set this property to `nil` to reset it to the default
  value.
-
+ 
  This property is only applied to the style if `iconImageName` is non-`nil`.
  Otherwise, it is ignored.
  */
@@ -929,13 +929,13 @@ MGL_EXPORT
 
 /**
  Fade out the halo towards the outside.
-
+ 
  This property is measured in points.
-
+ 
  The default value of this property is an `MGLStyleValue` object containing an
  `NSNumber` object containing the float `0`. Set this property to `nil` to reset
  it to the default value.
-
+ 
  This property is only applied to the style if `iconImageName` is non-`nil`.
  Otherwise, it is ignored.
  */
@@ -945,11 +945,11 @@ MGL_EXPORT
 /**
  The color of the icon’s halo. The `iconImageName` property must be set to a
  template image.
-
+ 
  The default value of this property is an `MGLStyleValue` object containing
  `UIColor.clearColor`. Set this property to `nil` to reset it to the default
  value.
-
+ 
  This property is only applied to the style if `iconImageName` is non-`nil`.
  Otherwise, it is ignored.
  */
@@ -958,11 +958,11 @@ MGL_EXPORT
 /**
  The color of the icon’s halo. The `iconImageName` property must be set to a
  template image.
-
+ 
  The default value of this property is an `MGLStyleValue` object containing
  `NSColor.clearColor`. Set this property to `nil` to reset it to the default
  value.
-
+ 
  This property is only applied to the style if `iconImageName` is non-`nil`.
  Otherwise, it is ignored.
  */
@@ -971,13 +971,13 @@ MGL_EXPORT
 
 /**
  Distance of halo to the icon outline.
-
+ 
  This property is measured in points.
-
+ 
  The default value of this property is an `MGLStyleValue` object containing an
  `NSNumber` object containing the float `0`. Set this property to `nil` to reset
  it to the default value.
-
+ 
  This property is only applied to the style if `iconImageName` is non-`nil`.
  Otherwise, it is ignored.
  */
@@ -985,11 +985,11 @@ MGL_EXPORT
 
 /**
  The opacity at which the icon will be drawn.
-
+ 
  The default value of this property is an `MGLStyleValue` object containing an
  `NSNumber` object containing the float `1`. Set this property to `nil` to reset
  it to the default value.
-
+ 
  This property is only applied to the style if `iconImageName` is non-`nil`.
  Otherwise, it is ignored.
  */
@@ -998,16 +998,16 @@ MGL_EXPORT
 #if TARGET_OS_IPHONE
 /**
  Distance that the icon's anchor is moved from its original placement.
-
+ 
  This property is measured in points.
-
+ 
  The default value of this property is an `MGLStyleValue` object containing an
  `NSValue` object containing a `CGVector` struct set to 0 points rightward and 0
  points downward. Set this property to `nil` to reset it to the default value.
-
+ 
  This property is only applied to the style if `iconImageName` is non-`nil`.
  Otherwise, it is ignored.
-
+ 
  This attribute corresponds to the <a
  href="https://www.mapbox.com/mapbox-gl-style-spec/#paint-icon-translate"><code>icon-translate</code></a>
  layout property in the Mapbox Style Specification.
@@ -1016,16 +1016,16 @@ MGL_EXPORT
 #else
 /**
  Distance that the icon's anchor is moved from its original placement.
-
+ 
  This property is measured in points.
-
+ 
  The default value of this property is an `MGLStyleValue` object containing an
  `NSValue` object containing a `CGVector` struct set to 0 points rightward and 0
  points upward. Set this property to `nil` to reset it to the default value.
-
+ 
  This property is only applied to the style if `iconImageName` is non-`nil`.
  Otherwise, it is ignored.
-
+ 
  This attribute corresponds to the <a
  href="https://www.mapbox.com/mapbox-gl-style-spec/#paint-icon-translate"><code>icon-translate</code></a>
  layout property in the Mapbox Style Specification.
@@ -1037,14 +1037,14 @@ MGL_EXPORT
 
 /**
  Controls the translation reference point.
-
+ 
  The default value of this property is an `MGLStyleValue` object containing an
  `NSValue` object containing `MGLIconTranslationAnchorMap`. Set this property to
  `nil` to reset it to the default value.
-
+ 
  This property is only applied to the style if `iconImageName` is non-`nil`, and
  `iconTranslation` is non-`nil`. Otherwise, it is ignored.
-
+ 
  This attribute corresponds to the <a
  href="https://www.mapbox.com/mapbox-gl-style-spec/#paint-icon-translate-anchor"><code>icon-translate-anchor</code></a>
  layout property in the Mapbox Style Specification.
@@ -1056,11 +1056,11 @@ MGL_EXPORT
 #if TARGET_OS_IPHONE
 /**
  The color with which the text will be drawn.
-
+ 
  The default value of this property is an `MGLStyleValue` object containing
  `UIColor.blackColor`. Set this property to `nil` to reset it to the default
  value.
-
+ 
  This property is only applied to the style if `text` is non-`nil`. Otherwise,
  it is ignored.
  */
@@ -1068,11 +1068,11 @@ MGL_EXPORT
 #else
 /**
  The color with which the text will be drawn.
-
+ 
  The default value of this property is an `MGLStyleValue` object containing
  `NSColor.blackColor`. Set this property to `nil` to reset it to the default
  value.
-
+ 
  This property is only applied to the style if `text` is non-`nil`. Otherwise,
  it is ignored.
  */
@@ -1081,13 +1081,13 @@ MGL_EXPORT
 
 /**
  The halo's fadeout distance towards the outside.
-
+ 
  This property is measured in points.
-
+ 
  The default value of this property is an `MGLStyleValue` object containing an
  `NSNumber` object containing the float `0`. Set this property to `nil` to reset
  it to the default value.
-
+ 
  This property is only applied to the style if `text` is non-`nil`. Otherwise,
  it is ignored.
  */
@@ -1096,11 +1096,11 @@ MGL_EXPORT
 #if TARGET_OS_IPHONE
 /**
  The color of the text's halo, which helps it stand out from backgrounds.
-
+ 
  The default value of this property is an `MGLStyleValue` object containing
  `UIColor.clearColor`. Set this property to `nil` to reset it to the default
  value.
-
+ 
  This property is only applied to the style if `text` is non-`nil`. Otherwise,
  it is ignored.
  */
@@ -1108,11 +1108,11 @@ MGL_EXPORT
 #else
 /**
  The color of the text's halo, which helps it stand out from backgrounds.
-
+ 
  The default value of this property is an `MGLStyleValue` object containing
  `NSColor.clearColor`. Set this property to `nil` to reset it to the default
  value.
-
+ 
  This property is only applied to the style if `text` is non-`nil`. Otherwise,
  it is ignored.
  */
@@ -1122,13 +1122,13 @@ MGL_EXPORT
 /**
  Distance of halo to the font outline. Max text halo width is 1/4 of the
  font-size.
-
+ 
  This property is measured in points.
-
+ 
  The default value of this property is an `MGLStyleValue` object containing an
  `NSNumber` object containing the float `0`. Set this property to `nil` to reset
  it to the default value.
-
+ 
  This property is only applied to the style if `text` is non-`nil`. Otherwise,
  it is ignored.
  */
@@ -1136,11 +1136,11 @@ MGL_EXPORT
 
 /**
  The opacity at which the text will be drawn.
-
+ 
  The default value of this property is an `MGLStyleValue` object containing an
  `NSNumber` object containing the float `1`. Set this property to `nil` to reset
  it to the default value.
-
+ 
  This property is only applied to the style if `text` is non-`nil`. Otherwise,
  it is ignored.
  */
@@ -1149,16 +1149,16 @@ MGL_EXPORT
 #if TARGET_OS_IPHONE
 /**
  Distance that the text's anchor is moved from its original placement.
-
+ 
  This property is measured in points.
-
+ 
  The default value of this property is an `MGLStyleValue` object containing an
  `NSValue` object containing a `CGVector` struct set to 0 points rightward and 0
  points downward. Set this property to `nil` to reset it to the default value.
-
+ 
  This property is only applied to the style if `text` is non-`nil`. Otherwise,
  it is ignored.
-
+ 
  This attribute corresponds to the <a
  href="https://www.mapbox.com/mapbox-gl-style-spec/#paint-text-translate"><code>text-translate</code></a>
  layout property in the Mapbox Style Specification.
@@ -1167,16 +1167,16 @@ MGL_EXPORT
 #else
 /**
  Distance that the text's anchor is moved from its original placement.
-
+ 
  This property is measured in points.
-
+ 
  The default value of this property is an `MGLStyleValue` object containing an
  `NSValue` object containing a `CGVector` struct set to 0 points rightward and 0
  points upward. Set this property to `nil` to reset it to the default value.
-
+ 
  This property is only applied to the style if `text` is non-`nil`. Otherwise,
  it is ignored.
-
+ 
  This attribute corresponds to the <a
  href="https://www.mapbox.com/mapbox-gl-style-spec/#paint-text-translate"><code>text-translate</code></a>
  layout property in the Mapbox Style Specification.
@@ -1188,14 +1188,14 @@ MGL_EXPORT
 
 /**
  Controls the translation reference point.
-
+ 
  The default value of this property is an `MGLStyleValue` object containing an
  `NSValue` object containing `MGLTextTranslationAnchorMap`. Set this property to
  `nil` to reset it to the default value.
-
+ 
  This property is only applied to the style if `text` is non-`nil`, and
  `textTranslation` is non-`nil`. Otherwise, it is ignored.
-
+ 
  This attribute corresponds to the <a
  href="https://www.mapbox.com/mapbox-gl-style-spec/#paint-text-translate-anchor"><code>text-translate-anchor</code></a>
  layout property in the Mapbox Style Specification.

platform/darwin/src/MGLSymbolStyleLayer.mm

@@ -197,7 +197,10 @@ namespace mbgl {
 - (MGLStyleValue<NSNumber *> *)iconAllowsOverlap {
     MGLAssertStyleLayerIsValid();
 
-    auto propertyValue = self.rawLayer->getIconAllowOverlap() ?: self.rawLayer->getDefaultIconAllowOverlap();
+    auto propertyValue = self.rawLayer->getIconAllowOverlap();
+    if (propertyValue.isUndefined()) {
+        return MGLStyleValueTransformer<bool, NSNumber *>().toStyleValue(self.rawLayer->getDefaultIconAllowOverlap());
+    }
     return MGLStyleValueTransformer<bool, NSNumber *>().toStyleValue(propertyValue);
 }
 
@@ -218,7 +221,10 @@ namespace mbgl {
 - (MGLStyleValue<NSNumber *> *)iconIgnoresPlacement {
     MGLAssertStyleLayerIsValid();
 
-    auto propertyValue = self.rawLayer->getIconIgnorePlacement() ?: self.rawLayer->getDefaultIconIgnorePlacement();
+    auto propertyValue = self.rawLayer->getIconIgnorePlacement();
+    if (propertyValue.isUndefined()) {
+        return MGLStyleValueTransformer<bool, NSNumber *>().toStyleValue(self.rawLayer->getDefaultIconIgnorePlacement());
+    }
     return MGLStyleValueTransformer<bool, NSNumber *>().toStyleValue(propertyValue);
 }
 
@@ -239,7 +245,10 @@ namespace mbgl {
 - (MGLStyleValue<NSString *> *)iconImageName {
     MGLAssertStyleLayerIsValid();
 
-    auto propertyValue = self.rawLayer->getIconImage() ?: self.rawLayer->getDefaultIconImage();
+    auto propertyValue = self.rawLayer->getIconImage();
+    if (propertyValue.isUndefined()) {
+        return MGLStyleValueTransformer<std::string, NSString *>().toStyleValue(self.rawLayer->getDefaultIconImage());
+    }
     return MGLStyleValueTransformer<std::string, NSString *>().toStyleValue(propertyValue);
 }
 
@@ -253,15 +262,18 @@ namespace mbgl {
 - (void)setIconOffset:(MGLStyleValue<NSValue *> *)iconOffset {
     MGLAssertStyleLayerIsValid();
 
-    auto mbglValue = MGLStyleValueTransformer<std::array<float, 2>, NSValue *>().toPropertyValue(iconOffset);
+    auto mbglValue = MGLStyleValueTransformer<std::array<float, 2>, NSValue *>().toDataDrivenPropertyValue(iconOffset);
     self.rawLayer->setIconOffset(mbglValue);
 }
 
 - (MGLStyleValue<NSValue *> *)iconOffset {
     MGLAssertStyleLayerIsValid();
 
-    auto propertyValue = self.rawLayer->getIconOffset() ?: self.rawLayer->getDefaultIconOffset();
-    return MGLStyleValueTransformer<std::array<float, 2>, NSValue *>().toStyleValue(propertyValue);
+    auto propertyValue = self.rawLayer->getIconOffset();
+    if (propertyValue.isUndefined()) {
+        return MGLStyleValueTransformer<std::array<float, 2>, NSValue *>().toDataDrivenStyleValue(self.rawLayer->getDefaultIconOffset());
+    }
+    return MGLStyleValueTransformer<std::array<float, 2>, NSValue *>().toDataDrivenStyleValue(propertyValue);
 }
 
 - (void)setIconOptional:(MGLStyleValue<NSNumber *> *)iconOptional {
@@ -274,36 +286,45 @@ namespace mbgl {
 - (MGLStyleValue<NSNumber *> *)isIconOptional {
     MGLAssertStyleLayerIsValid();
 
-    auto propertyValue = self.rawLayer->getIconOptional() ?: self.rawLayer->getDefaultIconOptional();
+    auto propertyValue = self.rawLayer->getIconOptional();
+    if (propertyValue.isUndefined()) {
+        return MGLStyleValueTransformer<bool, NSNumber *>().toStyleValue(self.rawLayer->getDefaultIconOptional());
+    }
     return MGLStyleValueTransformer<bool, NSNumber *>().toStyleValue(propertyValue);
 }
 
 - (void)setIconPadding:(MGLStyleValue<NSNumber *> *)iconPadding {
     MGLAssertStyleLayerIsValid();
 
-    auto mbglValue = MGLStyleValueTransformer<float, NSNumber *>().toPropertyValue(iconPadding);
+    auto mbglValue = MGLStyleValueTransformer<float, NSNumber *>().toInterpolatablePropertyValue(iconPadding);
     self.rawLayer->setIconPadding(mbglValue);
 }
 
 - (MGLStyleValue<NSNumber *> *)iconPadding {
     MGLAssertStyleLayerIsValid();
 
-    auto propertyValue = self.rawLayer->getIconPadding() ?: self.rawLayer->getDefaultIconPadding();
+    auto propertyValue = self.rawLayer->getIconPadding();
+    if (propertyValue.isUndefined()) {
+        return MGLStyleValueTransformer<float, NSNumber *>().toStyleValue(self.rawLayer->getDefaultIconPadding());
+    }
     return MGLStyleValueTransformer<float, NSNumber *>().toStyleValue(propertyValue);
 }
 
 - (void)setIconRotation:(MGLStyleValue<NSNumber *> *)iconRotation {
     MGLAssertStyleLayerIsValid();
 
-    auto mbglValue = MGLStyleValueTransformer<float, NSNumber *>().toPropertyValue(iconRotation);
+    auto mbglValue = MGLStyleValueTransformer<float, NSNumber *>().toDataDrivenPropertyValue(iconRotation);
     self.rawLayer->setIconRotate(mbglValue);
 }
 
 - (MGLStyleValue<NSNumber *> *)iconRotation {
     MGLAssertStyleLayerIsValid();
 
-    auto propertyValue = self.rawLayer->getIconRotate() ?: self.rawLayer->getDefaultIconRotate();
-    return MGLStyleValueTransformer<float, NSNumber *>().toStyleValue(propertyValue);
+    auto propertyValue = self.rawLayer->getIconRotate();
+    if (propertyValue.isUndefined()) {
+        return MGLStyleValueTransformer<float, NSNumber *>().toDataDrivenStyleValue(self.rawLayer->getDefaultIconRotate());
+    }
+    return MGLStyleValueTransformer<float, NSNumber *>().toDataDrivenStyleValue(propertyValue);
 }
 
 - (void)setIconRotate:(MGLStyleValue<NSNumber *> *)iconRotate {
@@ -323,21 +344,27 @@ namespace mbgl {
 - (MGLStyleValue<NSValue *> *)iconRotationAlignment {
     MGLAssertStyleLayerIsValid();
 
-    auto propertyValue = self.rawLayer->getIconRotationAlignment() ?: self.rawLayer->getDefaultIconRotationAlignment();
+    auto propertyValue = self.rawLayer->getIconRotationAlignment();
+    if (propertyValue.isUndefined()) {
+        return MGLStyleValueTransformer<mbgl::style::AlignmentType, NSValue *, mbgl::style::AlignmentType, MGLIconRotationAlignment>().toEnumStyleValue(self.rawLayer->getDefaultIconRotationAlignment());
+    }
     return MGLStyleValueTransformer<mbgl::style::AlignmentType, NSValue *, mbgl::style::AlignmentType, MGLIconRotationAlignment>().toEnumStyleValue(propertyValue);
 }
 
 - (void)setIconScale:(MGLStyleValue<NSNumber *> *)iconScale {
     MGLAssertStyleLayerIsValid();
 
-    auto mbglValue = MGLStyleValueTransformer<float, NSNumber *>().toPropertyValue(iconScale);
+    auto mbglValue = MGLStyleValueTransformer<float, NSNumber *>().toInterpolatablePropertyValue(iconScale);
     self.rawLayer->setIconSize(mbglValue);
 }
 
 - (MGLStyleValue<NSNumber *> *)iconScale {
     MGLAssertStyleLayerIsValid();
 
-    auto propertyValue = self.rawLayer->getIconSize() ?: self.rawLayer->getDefaultIconSize();
+    auto propertyValue = self.rawLayer->getIconSize();
+    if (propertyValue.isUndefined()) {
+        return MGLStyleValueTransformer<float, NSNumber *>().toStyleValue(self.rawLayer->getDefaultIconSize());
+    }
     return MGLStyleValueTransformer<float, NSNumber *>().toStyleValue(propertyValue);
 }
 
@@ -358,21 +385,27 @@ namespace mbgl {
 - (MGLStyleValue<NSValue *> *)iconTextFit {
     MGLAssertStyleLayerIsValid();
 
-    auto propertyValue = self.rawLayer->getIconTextFit() ?: self.rawLayer->getDefaultIconTextFit();
+    auto propertyValue = self.rawLayer->getIconTextFit();
+    if (propertyValue.isUndefined()) {
+        return MGLStyleValueTransformer<mbgl::style::IconTextFitType, NSValue *, mbgl::style::IconTextFitType, MGLIconTextFit>().toEnumStyleValue(self.rawLayer->getDefaultIconTextFit());
+    }
     return MGLStyleValueTransformer<mbgl::style::IconTextFitType, NSValue *, mbgl::style::IconTextFitType, MGLIconTextFit>().toEnumStyleValue(propertyValue);
 }
 
 - (void)setIconTextFitPadding:(MGLStyleValue<NSValue *> *)iconTextFitPadding {
     MGLAssertStyleLayerIsValid();
 
-    auto mbglValue = MGLStyleValueTransformer<std::array<float, 4>, NSValue *>().toPropertyValue(iconTextFitPadding);
+    auto mbglValue = MGLStyleValueTransformer<std::array<float, 4>, NSValue *>().toInterpolatablePropertyValue(iconTextFitPadding);
     self.rawLayer->setIconTextFitPadding(mbglValue);
 }
 
 - (MGLStyleValue<NSValue *> *)iconTextFitPadding {
     MGLAssertStyleLayerIsValid();
 
-    auto propertyValue = self.rawLayer->getIconTextFitPadding() ?: self.rawLayer->getDefaultIconTextFitPadding();
+    auto propertyValue = self.rawLayer->getIconTextFitPadding();
+    if (propertyValue.isUndefined()) {
+        return MGLStyleValueTransformer<std::array<float, 4>, NSValue *>().toStyleValue(self.rawLayer->getDefaultIconTextFitPadding());
+    }
     return MGLStyleValueTransformer<std::array<float, 4>, NSValue *>().toStyleValue(propertyValue);
 }
 
@@ -386,7 +419,10 @@ namespace mbgl {
 - (MGLStyleValue<NSNumber *> *)keepsIconUpright {
     MGLAssertStyleLayerIsValid();
 
-    auto propertyValue = self.rawLayer->getIconKeepUpright() ?: self.rawLayer->getDefaultIconKeepUpright();
+    auto propertyValue = self.rawLayer->getIconKeepUpright();
+    if (propertyValue.isUndefined()) {
+        return MGLStyleValueTransformer<bool, NSNumber *>().toStyleValue(self.rawLayer->getDefaultIconKeepUpright());
+    }
     return MGLStyleValueTransformer<bool, NSNumber *>().toStyleValue(propertyValue);
 }
 
@@ -407,7 +443,10 @@ namespace mbgl {
 - (MGLStyleValue<NSNumber *> *)keepsTextUpright {
     MGLAssertStyleLayerIsValid();
 
-    auto propertyValue = self.rawLayer->getTextKeepUpright() ?: self.rawLayer->getDefaultTextKeepUpright();
+    auto propertyValue = self.rawLayer->getTextKeepUpright();
+    if (propertyValue.isUndefined()) {
+        return MGLStyleValueTransformer<bool, NSNumber *>().toStyleValue(self.rawLayer->getDefaultTextKeepUpright());
+    }
     return MGLStyleValueTransformer<bool, NSNumber *>().toStyleValue(propertyValue);
 }
 
@@ -421,14 +460,17 @@ namespace mbgl {
 - (void)setMaximumTextAngle:(MGLStyleValue<NSNumber *> *)maximumTextAngle {
     MGLAssertStyleLayerIsValid();
 
-    auto mbglValue = MGLStyleValueTransformer<float, NSNumber *>().toPropertyValue(maximumTextAngle);
+    auto mbglValue = MGLStyleValueTransformer<float, NSNumber *>().toInterpolatablePropertyValue(maximumTextAngle);
     self.rawLayer->setTextMaxAngle(mbglValue);
 }
 
 - (MGLStyleValue<NSNumber *> *)maximumTextAngle {
     MGLAssertStyleLayerIsValid();
 
-    auto propertyValue = self.rawLayer->getTextMaxAngle() ?: self.rawLayer->getDefaultTextMaxAngle();
+    auto propertyValue = self.rawLayer->getTextMaxAngle();
+    if (propertyValue.isUndefined()) {
+        return MGLStyleValueTransformer<float, NSNumber *>().toStyleValue(self.rawLayer->getDefaultTextMaxAngle());
+    }
     return MGLStyleValueTransformer<float, NSNumber *>().toStyleValue(propertyValue);
 }
 
@@ -442,14 +484,17 @@ namespace mbgl {
 - (void)setMaximumTextWidth:(MGLStyleValue<NSNumber *> *)maximumTextWidth {
     MGLAssertStyleLayerIsValid();
 
-    auto mbglValue = MGLStyleValueTransformer<float, NSNumber *>().toPropertyValue(maximumTextWidth);
+    auto mbglValue = MGLStyleValueTransformer<float, NSNumber *>().toInterpolatablePropertyValue(maximumTextWidth);
     self.rawLayer->setTextMaxWidth(mbglValue);
 }
 
 - (MGLStyleValue<NSNumber *> *)maximumTextWidth {
     MGLAssertStyleLayerIsValid();
 
-    auto propertyValue = self.rawLayer->getTextMaxWidth() ?: self.rawLayer->getDefaultTextMaxWidth();
+    auto propertyValue = self.rawLayer->getTextMaxWidth();
+    if (propertyValue.isUndefined()) {
+        return MGLStyleValueTransformer<float, NSNumber *>().toStyleValue(self.rawLayer->getDefaultTextMaxWidth());
+    }
     return MGLStyleValueTransformer<float, NSNumber *>().toStyleValue(propertyValue);
 }
 
@@ -470,7 +515,10 @@ namespace mbgl {
 - (MGLStyleValue<NSNumber *> *)symbolAvoidsEdges {
     MGLAssertStyleLayerIsValid();
 
-    auto propertyValue = self.rawLayer->getSymbolAvoidEdges() ?: self.rawLayer->getDefaultSymbolAvoidEdges();
+    auto propertyValue = self.rawLayer->getSymbolAvoidEdges();
+    if (propertyValue.isUndefined()) {
+        return MGLStyleValueTransformer<bool, NSNumber *>().toStyleValue(self.rawLayer->getDefaultSymbolAvoidEdges());
+    }
     return MGLStyleValueTransformer<bool, NSNumber *>().toStyleValue(propertyValue);
 }
 
@@ -491,21 +539,27 @@ namespace mbgl {
 - (MGLStyleValue<NSValue *> *)symbolPlacement {
     MGLAssertStyleLayerIsValid();
 
-    auto propertyValue = self.rawLayer->getSymbolPlacement() ?: self.rawLayer->getDefaultSymbolPlacement();
+    auto propertyValue = self.rawLayer->getSymbolPlacement();
+    if (propertyValue.isUndefined()) {
+        return MGLStyleValueTransformer<mbgl::style::SymbolPlacementType, NSValue *, mbgl::style::SymbolPlacementType, MGLSymbolPlacement>().toEnumStyleValue(self.rawLayer->getDefaultSymbolPlacement());
+    }
     return MGLStyleValueTransformer<mbgl::style::SymbolPlacementType, NSValue *, mbgl::style::SymbolPlacementType, MGLSymbolPlacement>().toEnumStyleValue(propertyValue);
 }
 
 - (void)setSymbolSpacing:(MGLStyleValue<NSNumber *> *)symbolSpacing {
     MGLAssertStyleLayerIsValid();
 
-    auto mbglValue = MGLStyleValueTransformer<float, NSNumber *>().toPropertyValue(symbolSpacing);
+    auto mbglValue = MGLStyleValueTransformer<float, NSNumber *>().toInterpolatablePropertyValue(symbolSpacing);
     self.rawLayer->setSymbolSpacing(mbglValue);
 }
 
 - (MGLStyleValue<NSNumber *> *)symbolSpacing {
     MGLAssertStyleLayerIsValid();
 
-    auto propertyValue = self.rawLayer->getSymbolSpacing() ?: self.rawLayer->getDefaultSymbolSpacing();
+    auto propertyValue = self.rawLayer->getSymbolSpacing();
+    if (propertyValue.isUndefined()) {
+        return MGLStyleValueTransformer<float, NSNumber *>().toStyleValue(self.rawLayer->getDefaultSymbolSpacing());
+    }
     return MGLStyleValueTransformer<float, NSNumber *>().toStyleValue(propertyValue);
 }
 
@@ -519,7 +573,10 @@ namespace mbgl {
 - (MGLStyleValue<NSString *> *)text {
     MGLAssertStyleLayerIsValid();
 
-    auto propertyValue = self.rawLayer->getTextField() ?: self.rawLayer->getDefaultTextField();
+    auto propertyValue = self.rawLayer->getTextField();
+    if (propertyValue.isUndefined()) {
+        return MGLStyleValueTransformer<std::string, NSString *>().toStyleValue(self.rawLayer->getDefaultTextField());
+    }
     return MGLStyleValueTransformer<std::string, NSString *>().toStyleValue(propertyValue);
 }
 
@@ -540,7 +597,10 @@ namespace mbgl {
 - (MGLStyleValue<NSNumber *> *)textAllowsOverlap {
     MGLAssertStyleLayerIsValid();
 
-    auto propertyValue = self.rawLayer->getTextAllowOverlap() ?: self.rawLayer->getDefaultTextAllowOverlap();
+    auto propertyValue = self.rawLayer->getTextAllowOverlap();
+    if (propertyValue.isUndefined()) {
+        return MGLStyleValueTransformer<bool, NSNumber *>().toStyleValue(self.rawLayer->getDefaultTextAllowOverlap());
+    }
     return MGLStyleValueTransformer<bool, NSNumber *>().toStyleValue(propertyValue);
 }
 
@@ -561,7 +621,10 @@ namespace mbgl {
 - (MGLStyleValue<NSValue *> *)textAnchor {
     MGLAssertStyleLayerIsValid();
 
-    auto propertyValue = self.rawLayer->getTextAnchor() ?: self.rawLayer->getDefaultTextAnchor();
+    auto propertyValue = self.rawLayer->getTextAnchor();
+    if (propertyValue.isUndefined()) {
+        return MGLStyleValueTransformer<mbgl::style::TextAnchorType, NSValue *, mbgl::style::TextAnchorType, MGLTextAnchor>().toEnumStyleValue(self.rawLayer->getDefaultTextAnchor());
+    }
     return MGLStyleValueTransformer<mbgl::style::TextAnchorType, NSValue *, mbgl::style::TextAnchorType, MGLTextAnchor>().toEnumStyleValue(propertyValue);
 }
 
@@ -575,7 +638,10 @@ namespace mbgl {
 - (MGLStyleValue<NSArray<NSString *> *> *)textFontNames {
     MGLAssertStyleLayerIsValid();
 
-    auto propertyValue = self.rawLayer->getTextFont() ?: self.rawLayer->getDefaultTextFont();
+    auto propertyValue = self.rawLayer->getTextFont();
+    if (propertyValue.isUndefined()) {
+        return MGLStyleValueTransformer<std::vector<std::string>, NSArray<NSString *> *, std::string>().toStyleValue(self.rawLayer->getDefaultTextFont());
+    }
     return MGLStyleValueTransformer<std::vector<std::string>, NSArray<NSString *> *, std::string>().toStyleValue(propertyValue);
 }
 
@@ -589,14 +655,17 @@ namespace mbgl {
 - (void)setTextFontSize:(MGLStyleValue<NSNumber *> *)textFontSize {
     MGLAssertStyleLayerIsValid();
 
-    auto mbglValue = MGLStyleValueTransformer<float, NSNumber *>().toPropertyValue(textFontSize);
+    auto mbglValue = MGLStyleValueTransformer<float, NSNumber *>().toInterpolatablePropertyValue(textFontSize);
     self.rawLayer->setTextSize(mbglValue);
 }
 
 - (MGLStyleValue<NSNumber *> *)textFontSize {
     MGLAssertStyleLayerIsValid();
 
-    auto propertyValue = self.rawLayer->getTextSize() ?: self.rawLayer->getDefaultTextSize();
+    auto propertyValue = self.rawLayer->getTextSize();
+    if (propertyValue.isUndefined()) {
+        return MGLStyleValueTransformer<float, NSNumber *>().toStyleValue(self.rawLayer->getDefaultTextSize());
+    }
     return MGLStyleValueTransformer<float, NSNumber *>().toStyleValue(propertyValue);
 }
 
@@ -617,7 +686,10 @@ namespace mbgl {
 - (MGLStyleValue<NSNumber *> *)textIgnoresPlacement {
     MGLAssertStyleLayerIsValid();
 
-    auto propertyValue = self.rawLayer->getTextIgnorePlacement() ?: self.rawLayer->getDefaultTextIgnorePlacement();
+    auto propertyValue = self.rawLayer->getTextIgnorePlacement();
+    if (propertyValue.isUndefined()) {
+        return MGLStyleValueTransformer<bool, NSNumber *>().toStyleValue(self.rawLayer->getDefaultTextIgnorePlacement());
+    }
     return MGLStyleValueTransformer<bool, NSNumber *>().toStyleValue(propertyValue);
 }
 
@@ -638,7 +710,10 @@ namespace mbgl {
 - (MGLStyleValue<NSValue *> *)textJustification {
     MGLAssertStyleLayerIsValid();
 
-    auto propertyValue = self.rawLayer->getTextJustify() ?: self.rawLayer->getDefaultTextJustify();
+    auto propertyValue = self.rawLayer->getTextJustify();
+    if (propertyValue.isUndefined()) {
+        return MGLStyleValueTransformer<mbgl::style::TextJustifyType, NSValue *, mbgl::style::TextJustifyType, MGLTextJustification>().toEnumStyleValue(self.rawLayer->getDefaultTextJustify());
+    }
     return MGLStyleValueTransformer<mbgl::style::TextJustifyType, NSValue *, mbgl::style::TextJustifyType, MGLTextJustification>().toEnumStyleValue(propertyValue);
 }
 
@@ -652,42 +727,51 @@ namespace mbgl {
 - (void)setTextLetterSpacing:(MGLStyleValue<NSNumber *> *)textLetterSpacing {
     MGLAssertStyleLayerIsValid();
 
-    auto mbglValue = MGLStyleValueTransformer<float, NSNumber *>().toPropertyValue(textLetterSpacing);
+    auto mbglValue = MGLStyleValueTransformer<float, NSNumber *>().toInterpolatablePropertyValue(textLetterSpacing);
     self.rawLayer->setTextLetterSpacing(mbglValue);
 }
 
 - (MGLStyleValue<NSNumber *> *)textLetterSpacing {
     MGLAssertStyleLayerIsValid();
 
-    auto propertyValue = self.rawLayer->getTextLetterSpacing() ?: self.rawLayer->getDefaultTextLetterSpacing();
+    auto propertyValue = self.rawLayer->getTextLetterSpacing();
+    if (propertyValue.isUndefined()) {
+        return MGLStyleValueTransformer<float, NSNumber *>().toStyleValue(self.rawLayer->getDefaultTextLetterSpacing());
+    }
     return MGLStyleValueTransformer<float, NSNumber *>().toStyleValue(propertyValue);
 }
 
 - (void)setTextLineHeight:(MGLStyleValue<NSNumber *> *)textLineHeight {
     MGLAssertStyleLayerIsValid();
 
-    auto mbglValue = MGLStyleValueTransformer<float, NSNumber *>().toPropertyValue(textLineHeight);
+    auto mbglValue = MGLStyleValueTransformer<float, NSNumber *>().toInterpolatablePropertyValue(textLineHeight);
     self.rawLayer->setTextLineHeight(mbglValue);
 }
 
 - (MGLStyleValue<NSNumber *> *)textLineHeight {
     MGLAssertStyleLayerIsValid();
 
-    auto propertyValue = self.rawLayer->getTextLineHeight() ?: self.rawLayer->getDefaultTextLineHeight();
+    auto propertyValue = self.rawLayer->getTextLineHeight();
+    if (propertyValue.isUndefined()) {
+        return MGLStyleValueTransformer<float, NSNumber *>().toStyleValue(self.rawLayer->getDefaultTextLineHeight());
+    }
     return MGLStyleValueTransformer<float, NSNumber *>().toStyleValue(propertyValue);
 }
 
 - (void)setTextOffset:(MGLStyleValue<NSValue *> *)textOffset {
     MGLAssertStyleLayerIsValid();
 
-    auto mbglValue = MGLStyleValueTransformer<std::array<float, 2>, NSValue *>().toPropertyValue(textOffset);
+    auto mbglValue = MGLStyleValueTransformer<std::array<float, 2>, NSValue *>().toInterpolatablePropertyValue(textOffset);
     self.rawLayer->setTextOffset(mbglValue);
 }
 
 - (MGLStyleValue<NSValue *> *)textOffset {
     MGLAssertStyleLayerIsValid();
 
-    auto propertyValue = self.rawLayer->getTextOffset() ?: self.rawLayer->getDefaultTextOffset();
+    auto propertyValue = self.rawLayer->getTextOffset();
+    if (propertyValue.isUndefined()) {
+        return MGLStyleValueTransformer<std::array<float, 2>, NSValue *>().toStyleValue(self.rawLayer->getDefaultTextOffset());
+    }
     return MGLStyleValueTransformer<std::array<float, 2>, NSValue *>().toStyleValue(propertyValue);
 }
 
@@ -701,21 +785,27 @@ namespace mbgl {
 - (MGLStyleValue<NSNumber *> *)isTextOptional {
     MGLAssertStyleLayerIsValid();
 
-    auto propertyValue = self.rawLayer->getTextOptional() ?: self.rawLayer->getDefaultTextOptional();
+    auto propertyValue = self.rawLayer->getTextOptional();
+    if (propertyValue.isUndefined()) {
+        return MGLStyleValueTransformer<bool, NSNumber *>().toStyleValue(self.rawLayer->getDefaultTextOptional());
+    }
     return MGLStyleValueTransformer<bool, NSNumber *>().toStyleValue(propertyValue);
 }
 
 - (void)setTextPadding:(MGLStyleValue<NSNumber *> *)textPadding {
     MGLAssertStyleLayerIsValid();
 
-    auto mbglValue = MGLStyleValueTransformer<float, NSNumber *>().toPropertyValue(textPadding);
+    auto mbglValue = MGLStyleValueTransformer<float, NSNumber *>().toInterpolatablePropertyValue(textPadding);
     self.rawLayer->setTextPadding(mbglValue);
 }
 
 - (MGLStyleValue<NSNumber *> *)textPadding {
     MGLAssertStyleLayerIsValid();
 
-    auto propertyValue = self.rawLayer->getTextPadding() ?: self.rawLayer->getDefaultTextPadding();
+    auto propertyValue = self.rawLayer->getTextPadding();
+    if (propertyValue.isUndefined()) {
+        return MGLStyleValueTransformer<float, NSNumber *>().toStyleValue(self.rawLayer->getDefaultTextPadding());
+    }
     return MGLStyleValueTransformer<float, NSNumber *>().toStyleValue(propertyValue);
 }
 
@@ -729,21 +819,27 @@ namespace mbgl {
 - (MGLStyleValue<NSValue *> *)textPitchAlignment {
     MGLAssertStyleLayerIsValid();
 
-    auto propertyValue = self.rawLayer->getTextPitchAlignment() ?: self.rawLayer->getDefaultTextPitchAlignment();
+    auto propertyValue = self.rawLayer->getTextPitchAlignment();
+    if (propertyValue.isUndefined()) {
+        return MGLStyleValueTransformer<mbgl::style::AlignmentType, NSValue *, mbgl::style::AlignmentType, MGLTextPitchAlignment>().toEnumStyleValue(self.rawLayer->getDefaultTextPitchAlignment());
+    }
     return MGLStyleValueTransformer<mbgl::style::AlignmentType, NSValue *, mbgl::style::AlignmentType, MGLTextPitchAlignment>().toEnumStyleValue(propertyValue);
 }
 
 - (void)setTextRotation:(MGLStyleValue<NSNumber *> *)textRotation {
     MGLAssertStyleLayerIsValid();
 
-    auto mbglValue = MGLStyleValueTransformer<float, NSNumber *>().toPropertyValue(textRotation);
+    auto mbglValue = MGLStyleValueTransformer<float, NSNumber *>().toInterpolatablePropertyValue(textRotation);
     self.rawLayer->setTextRotate(mbglValue);
 }
 
 - (MGLStyleValue<NSNumber *> *)textRotation {
     MGLAssertStyleLayerIsValid();
 
-    auto propertyValue = self.rawLayer->getTextRotate() ?: self.rawLayer->getDefaultTextRotate();
+    auto propertyValue = self.rawLayer->getTextRotate();
+    if (propertyValue.isUndefined()) {
+        return MGLStyleValueTransformer<float, NSNumber *>().toStyleValue(self.rawLayer->getDefaultTextRotate());
+    }
     return MGLStyleValueTransformer<float, NSNumber *>().toStyleValue(propertyValue);
 }
 
@@ -764,7 +860,10 @@ namespace mbgl {
 - (MGLStyleValue<NSValue *> *)textRotationAlignment {
     MGLAssertStyleLayerIsValid();
 
-    auto propertyValue = self.rawLayer->getTextRotationAlignment() ?: self.rawLayer->getDefaultTextRotationAlignment();
+    auto propertyValue = self.rawLayer->getTextRotationAlignment();
+    if (propertyValue.isUndefined()) {
+        return MGLStyleValueTransformer<mbgl::style::AlignmentType, NSValue *, mbgl::style::AlignmentType, MGLTextRotationAlignment>().toEnumStyleValue(self.rawLayer->getDefaultTextRotationAlignment());
+    }
     return MGLStyleValueTransformer<mbgl::style::AlignmentType, NSValue *, mbgl::style::AlignmentType, MGLTextRotationAlignment>().toEnumStyleValue(propertyValue);
 }
 
@@ -778,7 +877,10 @@ namespace mbgl {
 - (MGLStyleValue<NSValue *> *)textTransform {
     MGLAssertStyleLayerIsValid();
 
-    auto propertyValue = self.rawLayer->getTextTransform() ?: self.rawLayer->getDefaultTextTransform();
+    auto propertyValue = self.rawLayer->getTextTransform();
+    if (propertyValue.isUndefined()) {
+        return MGLStyleValueTransformer<mbgl::style::TextTransformType, NSValue *, mbgl::style::TextTransformType, MGLTextTransform>().toEnumStyleValue(self.rawLayer->getDefaultTextTransform());
+    }
     return MGLStyleValueTransformer<mbgl::style::TextTransformType, NSValue *, mbgl::style::TextTransformType, MGLTextTransform>().toEnumStyleValue(propertyValue);
 }
 
@@ -787,84 +889,102 @@ namespace mbgl {
 - (void)setIconColor:(MGLStyleValue<MGLColor *> *)iconColor {
     MGLAssertStyleLayerIsValid();
 
-    auto mbglValue = MGLStyleValueTransformer<mbgl::Color, MGLColor *>().toPropertyValue(iconColor);
+    auto mbglValue = MGLStyleValueTransformer<mbgl::Color, MGLColor *>().toInterpolatablePropertyValue(iconColor);
     self.rawLayer->setIconColor(mbglValue);
 }
 
 - (MGLStyleValue<MGLColor *> *)iconColor {
     MGLAssertStyleLayerIsValid();
 
-    auto propertyValue = self.rawLayer->getIconColor() ?: self.rawLayer->getDefaultIconColor();
+    auto propertyValue = self.rawLayer->getIconColor();
+    if (propertyValue.isUndefined()) {
+        return MGLStyleValueTransformer<mbgl::Color, MGLColor *>().toStyleValue(self.rawLayer->getDefaultIconColor());
+    }
     return MGLStyleValueTransformer<mbgl::Color, MGLColor *>().toStyleValue(propertyValue);
 }
 
 - (void)setIconHaloBlur:(MGLStyleValue<NSNumber *> *)iconHaloBlur {
     MGLAssertStyleLayerIsValid();
 
-    auto mbglValue = MGLStyleValueTransformer<float, NSNumber *>().toPropertyValue(iconHaloBlur);
+    auto mbglValue = MGLStyleValueTransformer<float, NSNumber *>().toInterpolatablePropertyValue(iconHaloBlur);
     self.rawLayer->setIconHaloBlur(mbglValue);
 }
 
 - (MGLStyleValue<NSNumber *> *)iconHaloBlur {
     MGLAssertStyleLayerIsValid();
 
-    auto propertyValue = self.rawLayer->getIconHaloBlur() ?: self.rawLayer->getDefaultIconHaloBlur();
+    auto propertyValue = self.rawLayer->getIconHaloBlur();
+    if (propertyValue.isUndefined()) {
+        return MGLStyleValueTransformer<float, NSNumber *>().toStyleValue(self.rawLayer->getDefaultIconHaloBlur());
+    }
     return MGLStyleValueTransformer<float, NSNumber *>().toStyleValue(propertyValue);
 }
 
 - (void)setIconHaloColor:(MGLStyleValue<MGLColor *> *)iconHaloColor {
     MGLAssertStyleLayerIsValid();
 
-    auto mbglValue = MGLStyleValueTransformer<mbgl::Color, MGLColor *>().toPropertyValue(iconHaloColor);
+    auto mbglValue = MGLStyleValueTransformer<mbgl::Color, MGLColor *>().toInterpolatablePropertyValue(iconHaloColor);
     self.rawLayer->setIconHaloColor(mbglValue);
 }
 
 - (MGLStyleValue<MGLColor *> *)iconHaloColor {
     MGLAssertStyleLayerIsValid();
 
-    auto propertyValue = self.rawLayer->getIconHaloColor() ?: self.rawLayer->getDefaultIconHaloColor();
+    auto propertyValue = self.rawLayer->getIconHaloColor();
+    if (propertyValue.isUndefined()) {
+        return MGLStyleValueTransformer<mbgl::Color, MGLColor *>().toStyleValue(self.rawLayer->getDefaultIconHaloColor());
+    }
     return MGLStyleValueTransformer<mbgl::Color, MGLColor *>().toStyleValue(propertyValue);
 }
 
 - (void)setIconHaloWidth:(MGLStyleValue<NSNumber *> *)iconHaloWidth {
     MGLAssertStyleLayerIsValid();
 
-    auto mbglValue = MGLStyleValueTransformer<float, NSNumber *>().toPropertyValue(iconHaloWidth);
+    auto mbglValue = MGLStyleValueTransformer<float, NSNumber *>().toInterpolatablePropertyValue(iconHaloWidth);
     self.rawLayer->setIconHaloWidth(mbglValue);
 }
 
 - (MGLStyleValue<NSNumber *> *)iconHaloWidth {
     MGLAssertStyleLayerIsValid();
 
-    auto propertyValue = self.rawLayer->getIconHaloWidth() ?: self.rawLayer->getDefaultIconHaloWidth();
+    auto propertyValue = self.rawLayer->getIconHaloWidth();
+    if (propertyValue.isUndefined()) {
+        return MGLStyleValueTransformer<float, NSNumber *>().toStyleValue(self.rawLayer->getDefaultIconHaloWidth());
+    }
     return MGLStyleValueTransformer<float, NSNumber *>().toStyleValue(propertyValue);
 }
 
 - (void)setIconOpacity:(MGLStyleValue<NSNumber *> *)iconOpacity {
     MGLAssertStyleLayerIsValid();
 
-    auto mbglValue = MGLStyleValueTransformer<float, NSNumber *>().toPropertyValue(iconOpacity);
+    auto mbglValue = MGLStyleValueTransformer<float, NSNumber *>().toInterpolatablePropertyValue(iconOpacity);
     self.rawLayer->setIconOpacity(mbglValue);
 }
 
 - (MGLStyleValue<NSNumber *> *)iconOpacity {
     MGLAssertStyleLayerIsValid();
 
-    auto propertyValue = self.rawLayer->getIconOpacity() ?: self.rawLayer->getDefaultIconOpacity();
+    auto propertyValue = self.rawLayer->getIconOpacity();
+    if (propertyValue.isUndefined()) {
+        return MGLStyleValueTransformer<float, NSNumber *>().toStyleValue(self.rawLayer->getDefaultIconOpacity());
+    }
     return MGLStyleValueTransformer<float, NSNumber *>().toStyleValue(propertyValue);
 }
 
 - (void)setIconTranslation:(MGLStyleValue<NSValue *> *)iconTranslation {
     MGLAssertStyleLayerIsValid();
 
-    auto mbglValue = MGLStyleValueTransformer<std::array<float, 2>, NSValue *>().toPropertyValue(iconTranslation);
+    auto mbglValue = MGLStyleValueTransformer<std::array<float, 2>, NSValue *>().toInterpolatablePropertyValue(iconTranslation);
     self.rawLayer->setIconTranslate(mbglValue);
 }
 
 - (MGLStyleValue<NSValue *> *)iconTranslation {
     MGLAssertStyleLayerIsValid();
 
-    auto propertyValue = self.rawLayer->getIconTranslate() ?: self.rawLayer->getDefaultIconTranslate();
+    auto propertyValue = self.rawLayer->getIconTranslate();
+    if (propertyValue.isUndefined()) {
+        return MGLStyleValueTransformer<std::array<float, 2>, NSValue *>().toStyleValue(self.rawLayer->getDefaultIconTranslate());
+    }
     return MGLStyleValueTransformer<std::array<float, 2>, NSValue *>().toStyleValue(propertyValue);
 }
 
@@ -885,7 +1005,10 @@ namespace mbgl {
 - (MGLStyleValue<NSValue *> *)iconTranslationAnchor {
     MGLAssertStyleLayerIsValid();
 
-    auto propertyValue = self.rawLayer->getIconTranslateAnchor() ?: self.rawLayer->getDefaultIconTranslateAnchor();
+    auto propertyValue = self.rawLayer->getIconTranslateAnchor();
+    if (propertyValue.isUndefined()) {
+        return MGLStyleValueTransformer<mbgl::style::TranslateAnchorType, NSValue *, mbgl::style::TranslateAnchorType, MGLIconTranslationAnchor>().toEnumStyleValue(self.rawLayer->getDefaultIconTranslateAnchor());
+    }
     return MGLStyleValueTransformer<mbgl::style::TranslateAnchorType, NSValue *, mbgl::style::TranslateAnchorType, MGLIconTranslationAnchor>().toEnumStyleValue(propertyValue);
 }
 
@@ -899,84 +1022,102 @@ namespace mbgl {
 - (void)setTextColor:(MGLStyleValue<MGLColor *> *)textColor {
     MGLAssertStyleLayerIsValid();
 
-    auto mbglValue = MGLStyleValueTransformer<mbgl::Color, MGLColor *>().toPropertyValue(textColor);
+    auto mbglValue = MGLStyleValueTransformer<mbgl::Color, MGLColor *>().toInterpolatablePropertyValue(textColor);
     self.rawLayer->setTextColor(mbglValue);
 }
 
 - (MGLStyleValue<MGLColor *> *)textColor {
     MGLAssertStyleLayerIsValid();
 
-    auto propertyValue = self.rawLayer->getTextColor() ?: self.rawLayer->getDefaultTextColor();
+    auto propertyValue = self.rawLayer->getTextColor();
+    if (propertyValue.isUndefined()) {
+        return MGLStyleValueTransformer<mbgl::Color, MGLColor *>().toStyleValue(self.rawLayer->getDefaultTextColor());
+    }
     return MGLStyleValueTransformer<mbgl::Color, MGLColor *>().toStyleValue(propertyValue);
 }
 
 - (void)setTextHaloBlur:(MGLStyleValue<NSNumber *> *)textHaloBlur {
     MGLAssertStyleLayerIsValid();
 
-    auto mbglValue = MGLStyleValueTransformer<float, NSNumber *>().toPropertyValue(textHaloBlur);
+    auto mbglValue = MGLStyleValueTransformer<float, NSNumber *>().toInterpolatablePropertyValue(textHaloBlur);
     self.rawLayer->setTextHaloBlur(mbglValue);
 }
 
 - (MGLStyleValue<NSNumber *> *)textHaloBlur {
     MGLAssertStyleLayerIsValid();
 
-    auto propertyValue = self.rawLayer->getTextHaloBlur() ?: self.rawLayer->getDefaultTextHaloBlur();
+    auto propertyValue = self.rawLayer->getTextHaloBlur();
+    if (propertyValue.isUndefined()) {
+        return MGLStyleValueTransformer<float, NSNumber *>().toStyleValue(self.rawLayer->getDefaultTextHaloBlur());
+    }
     return MGLStyleValueTransformer<float, NSNumber *>().toStyleValue(propertyValue);
 }
 
 - (void)setTextHaloColor:(MGLStyleValue<MGLColor *> *)textHaloColor {
     MGLAssertStyleLayerIsValid();
 
-    auto mbglValue = MGLStyleValueTransformer<mbgl::Color, MGLColor *>().toPropertyValue(textHaloColor);
+    auto mbglValue = MGLStyleValueTransformer<mbgl::Color, MGLColor *>().toInterpolatablePropertyValue(textHaloColor);
     self.rawLayer->setTextHaloColor(mbglValue);
 }
 
 - (MGLStyleValue<MGLColor *> *)textHaloColor {
     MGLAssertStyleLayerIsValid();
 
-    auto propertyValue = self.rawLayer->getTextHaloColor() ?: self.rawLayer->getDefaultTextHaloColor();
+    auto propertyValue = self.rawLayer->getTextHaloColor();
+    if (propertyValue.isUndefined()) {
+        return MGLStyleValueTransformer<mbgl::Color, MGLColor *>().toStyleValue(self.rawLayer->getDefaultTextHaloColor());
+    }
     return MGLStyleValueTransformer<mbgl::Color, MGLColor *>().toStyleValue(propertyValue);
 }
 
 - (void)setTextHaloWidth:(MGLStyleValue<NSNumber *> *)textHaloWidth {
     MGLAssertStyleLayerIsValid();
 
-    auto mbglValue = MGLStyleValueTransformer<float, NSNumber *>().toPropertyValue(textHaloWidth);
+    auto mbglValue = MGLStyleValueTransformer<float, NSNumber *>().toInterpolatablePropertyValue(textHaloWidth);
     self.rawLayer->setTextHaloWidth(mbglValue);
 }
 
 - (MGLStyleValue<NSNumber *> *)textHaloWidth {
     MGLAssertStyleLayerIsValid();
 
-    auto propertyValue = self.rawLayer->getTextHaloWidth() ?: self.rawLayer->getDefaultTextHaloWidth();
+    auto propertyValue = self.rawLayer->getTextHaloWidth();
+    if (propertyValue.isUndefined()) {
+        return MGLStyleValueTransformer<float, NSNumber *>().toStyleValue(self.rawLayer->getDefaultTextHaloWidth());
+    }
     return MGLStyleValueTransformer<float, NSNumber *>().toStyleValue(propertyValue);
 }
 
 - (void)setTextOpacity:(MGLStyleValue<NSNumber *> *)textOpacity {
     MGLAssertStyleLayerIsValid();
 
-    auto mbglValue = MGLStyleValueTransformer<float, NSNumber *>().toPropertyValue(textOpacity);
+    auto mbglValue = MGLStyleValueTransformer<float, NSNumber *>().toInterpolatablePropertyValue(textOpacity);
     self.rawLayer->setTextOpacity(mbglValue);
 }
 
 - (MGLStyleValue<NSNumber *> *)textOpacity {
     MGLAssertStyleLayerIsValid();
 
-    auto propertyValue = self.rawLayer->getTextOpacity() ?: self.rawLayer->getDefaultTextOpacity();
+    auto propertyValue = self.rawLayer->getTextOpacity();
+    if (propertyValue.isUndefined()) {
+        return MGLStyleValueTransformer<float, NSNumber *>().toStyleValue(self.rawLayer->getDefaultTextOpacity());
+    }
     return MGLStyleValueTransformer<float, NSNumber *>().toStyleValue(propertyValue);
 }
 
 - (void)setTextTranslation:(MGLStyleValue<NSValue *> *)textTranslation {
     MGLAssertStyleLayerIsValid();
 
-    auto mbglValue = MGLStyleValueTransformer<std::array<float, 2>, NSValue *>().toPropertyValue(textTranslation);
+    auto mbglValue = MGLStyleValueTransformer<std::array<float, 2>, NSValue *>().toInterpolatablePropertyValue(textTranslation);
     self.rawLayer->setTextTranslate(mbglValue);
 }
 
 - (MGLStyleValue<NSValue *> *)textTranslation {
     MGLAssertStyleLayerIsValid();
 
-    auto propertyValue = self.rawLayer->getTextTranslate() ?: self.rawLayer->getDefaultTextTranslate();
+    auto propertyValue = self.rawLayer->getTextTranslate();
+    if (propertyValue.isUndefined()) {
+        return MGLStyleValueTransformer<std::array<float, 2>, NSValue *>().toStyleValue(self.rawLayer->getDefaultTextTranslate());
+    }
     return MGLStyleValueTransformer<std::array<float, 2>, NSValue *>().toStyleValue(propertyValue);
 }
 
@@ -997,7 +1138,10 @@ namespace mbgl {
 - (MGLStyleValue<NSValue *> *)textTranslationAnchor {
     MGLAssertStyleLayerIsValid();
 
-    auto propertyValue = self.rawLayer->getTextTranslateAnchor() ?: self.rawLayer->getDefaultTextTranslateAnchor();
+    auto propertyValue = self.rawLayer->getTextTranslateAnchor();
+    if (propertyValue.isUndefined()) {
+        return MGLStyleValueTransformer<mbgl::style::TranslateAnchorType, NSValue *, mbgl::style::TranslateAnchorType, MGLTextTranslationAnchor>().toEnumStyleValue(self.rawLayer->getDefaultTextTranslateAnchor());
+    }
     return MGLStyleValueTransformer<mbgl::style::TranslateAnchorType, NSValue *, mbgl::style::TranslateAnchorType, MGLTextTranslationAnchor>().toEnumStyleValue(propertyValue);
 }
 

platform/darwin/test/MGLBackgroundStyleLayerTests.mm

@@ -1,5 +1,5 @@
 // This file is generated.
-// Edit platform/darwin/scripts/generate-style-code.js, then run `make style-code-darwin`.
+// Edit platform/darwin/scripts/generate-style-code.js, then run `make darwin-style-code`.
 
 #import "MGLStyleLayerTests.h"
 
@@ -28,26 +28,26 @@
                       @"background-color should be unset initially.");
         MGLStyleValue<MGLColor *> *defaultStyleValue = layer.backgroundColor;
 
-        MGLStyleValue<MGLColor *> *styleValue = [MGLStyleValue<MGLColor *> valueWithRawValue:[MGLColor redColor]];
-        layer.backgroundColor = styleValue;
+        MGLStyleValue<MGLColor *> *constantStyleValue = [MGLStyleValue<MGLColor *> valueWithRawValue:[MGLColor redColor]];
+        layer.backgroundColor = constantStyleValue;
         mbgl::style::PropertyValue<mbgl::Color> propertyValue = { { 1, 0, 0, 1 } };
         XCTAssertEqual(rawLayer->getBackgroundColor(), propertyValue,
                        @"Setting backgroundColor to a constant value should update background-color.");
-        XCTAssertEqualObjects(layer.backgroundColor, styleValue,
+        XCTAssertEqualObjects(layer.backgroundColor, constantStyleValue,
                               @"backgroundColor should round-trip constant values.");
 
-        styleValue = [MGLStyleValue<MGLColor *> valueWithStops:@{
-            @18: styleValue,
-        }];
-        layer.backgroundColor = styleValue;
-        propertyValue = { mbgl::style::Function<mbgl::Color> {
-            {{ 18, propertyValue.asConstant() }},
-            1,
-        }};
+        MGLStyleValue<MGLColor *> * functionStyleValue = [MGLStyleValue<MGLColor *> valueWithInterpolationMode:MGLInterpolationModeInterval cameraStops:@{@18: constantStyleValue} options:nil];
+        layer.backgroundColor = functionStyleValue;
+
+        mbgl::style::IntervalStops<mbgl::Color> intervalStops = { {{18, { 1, 0, 0, 1 }}} };
+        propertyValue = mbgl::style::CameraFunction<mbgl::Color> { intervalStops };
+        
         XCTAssertEqual(rawLayer->getBackgroundColor(), propertyValue,
-                       @"Setting backgroundColor to a function should update background-color.");
-        XCTAssertEqualObjects(layer.backgroundColor, styleValue,
-                              @"backgroundColor should round-trip functions.");
+                       @"Setting backgroundColor to a camera function should update background-color.");
+        XCTAssertEqualObjects(layer.backgroundColor, functionStyleValue,
+                              @"backgroundColor should round-trip camera functions.");
+
+                              
 
         layer.backgroundColor = nil;
         XCTAssertTrue(rawLayer->getBackgroundColor().isUndefined(),
@@ -62,26 +62,26 @@
                       @"background-opacity should be unset initially.");
         MGLStyleValue<NSNumber *> *defaultStyleValue = layer.backgroundOpacity;
 
-        MGLStyleValue<NSNumber *> *styleValue = [MGLStyleValue<NSNumber *> valueWithRawValue:@0xff];
-        layer.backgroundOpacity = styleValue;
+        MGLStyleValue<NSNumber *> *constantStyleValue = [MGLStyleValue<NSNumber *> valueWithRawValue:@0xff];
+        layer.backgroundOpacity = constantStyleValue;
         mbgl::style::PropertyValue<float> propertyValue = { 0xff };
         XCTAssertEqual(rawLayer->getBackgroundOpacity(), propertyValue,
                        @"Setting backgroundOpacity to a constant value should update background-opacity.");
-        XCTAssertEqualObjects(layer.backgroundOpacity, styleValue,
+        XCTAssertEqualObjects(layer.backgroundOpacity, constantStyleValue,
                               @"backgroundOpacity should round-trip constant values.");
 
-        styleValue = [MGLStyleValue<NSNumber *> valueWithStops:@{
-            @18: styleValue,
-        }];
-        layer.backgroundOpacity = styleValue;
-        propertyValue = { mbgl::style::Function<float> {
-            {{ 18, propertyValue.asConstant() }},
-            1,
-        }};
+        MGLStyleValue<NSNumber *> * functionStyleValue = [MGLStyleValue<NSNumber *> valueWithInterpolationMode:MGLInterpolationModeInterval cameraStops:@{@18: constantStyleValue} options:nil];
+        layer.backgroundOpacity = functionStyleValue;
+
+        mbgl::style::IntervalStops<float> intervalStops = { {{18, 0xff}} };
+        propertyValue = mbgl::style::CameraFunction<float> { intervalStops };
+        
         XCTAssertEqual(rawLayer->getBackgroundOpacity(), propertyValue,
-                       @"Setting backgroundOpacity to a function should update background-opacity.");
-        XCTAssertEqualObjects(layer.backgroundOpacity, styleValue,
-                              @"backgroundOpacity should round-trip functions.");
+                       @"Setting backgroundOpacity to a camera function should update background-opacity.");
+        XCTAssertEqualObjects(layer.backgroundOpacity, functionStyleValue,
+                              @"backgroundOpacity should round-trip camera functions.");
+
+                              
 
         layer.backgroundOpacity = nil;
         XCTAssertTrue(rawLayer->getBackgroundOpacity().isUndefined(),
@@ -96,32 +96,38 @@
                       @"background-pattern should be unset initially.");
         MGLStyleValue<NSString *> *defaultStyleValue = layer.backgroundPattern;
 
-        MGLStyleValue<NSString *> *styleValue = [MGLStyleValue<NSString *> valueWithRawValue:@"Background Pattern"];
-        layer.backgroundPattern = styleValue;
+        MGLStyleValue<NSString *> *constantStyleValue = [MGLStyleValue<NSString *> valueWithRawValue:@"Background Pattern"];
+        layer.backgroundPattern = constantStyleValue;
         mbgl::style::PropertyValue<std::string> propertyValue = { "Background Pattern" };
         XCTAssertEqual(rawLayer->getBackgroundPattern(), propertyValue,
                        @"Setting backgroundPattern to a constant value should update background-pattern.");
-        XCTAssertEqualObjects(layer.backgroundPattern, styleValue,
+        XCTAssertEqualObjects(layer.backgroundPattern, constantStyleValue,
                               @"backgroundPattern should round-trip constant values.");
 
-        styleValue = [MGLStyleValue<NSString *> valueWithStops:@{
-            @18: styleValue,
-        }];
-        layer.backgroundPattern = styleValue;
-        propertyValue = { mbgl::style::Function<std::string> {
-            {{ 18, propertyValue.asConstant() }},
-            1,
-        }};
+        MGLStyleValue<NSString *> * functionStyleValue = [MGLStyleValue<NSString *> valueWithInterpolationMode:MGLInterpolationModeInterval cameraStops:@{@18: constantStyleValue} options:nil];
+        layer.backgroundPattern = functionStyleValue;
+
+        mbgl::style::IntervalStops<std::string> intervalStops = { {{18, "Background Pattern"}} };
+        propertyValue = mbgl::style::CameraFunction<std::string> { intervalStops };
+        
         XCTAssertEqual(rawLayer->getBackgroundPattern(), propertyValue,
-                       @"Setting backgroundPattern to a function should update background-pattern.");
-        XCTAssertEqualObjects(layer.backgroundPattern, styleValue,
-                              @"backgroundPattern should round-trip functions.");
+                       @"Setting backgroundPattern to a camera function should update background-pattern.");
+        XCTAssertEqualObjects(layer.backgroundPattern, functionStyleValue,
+                              @"backgroundPattern should round-trip camera functions.");
+
+                              
 
         layer.backgroundPattern = nil;
         XCTAssertTrue(rawLayer->getBackgroundPattern().isUndefined(),
                       @"Unsetting backgroundPattern should return background-pattern to the default value.");
         XCTAssertEqualObjects(layer.backgroundPattern, defaultStyleValue,
                               @"backgroundPattern should return the default value after being unset.");
+
+        functionStyleValue = [MGLStyleValue<NSString *> valueWithInterpolationMode:MGLInterpolationModeIdentity sourceStops:nil attributeName:@"" options:nil];
+        XCTAssertThrowsSpecificNamed(layer.backgroundPattern = functionStyleValue, NSException, NSInvalidArgumentException, @"MGLStyleValue should raise an exception if it is applied to a property that cannot support it");
+
+        functionStyleValue = [MGLStyleValue<NSString *> valueWithInterpolationMode:MGLInterpolationModeInterval compositeStops:@{@18: constantStyleValue} attributeName:@"" options:nil];
+        XCTAssertThrowsSpecificNamed(layer.backgroundPattern = functionStyleValue, NSException, NSInvalidArgumentException, @"MGLStyleValue should raise an exception if it is applied to a property that cannot support it");        
     }
 }
 

platform/darwin/test/MGLCircleStyleLayerTests.mm

@@ -1,5 +1,5 @@
 // This file is generated.
-// Edit platform/darwin/scripts/generate-style-code.js, then run `make style-code-darwin`.
+// Edit platform/darwin/scripts/generate-style-code.js, then run `make darwin-style-code`.
 
 #import "MGLStyleLayerTests.h"
 
@@ -49,26 +49,49 @@
                       @"circle-blur should be unset initially.");
         MGLStyleValue<NSNumber *> *defaultStyleValue = layer.circleBlur;
 
-        MGLStyleValue<NSNumber *> *styleValue = [MGLStyleValue<NSNumber *> valueWithRawValue:@0xff];
-        layer.circleBlur = styleValue;
-        mbgl::style::PropertyValue<float> propertyValue = { 0xff };
+        MGLStyleValue<NSNumber *> *constantStyleValue = [MGLStyleValue<NSNumber *> valueWithRawValue:@0xff];
+        layer.circleBlur = constantStyleValue;
+        mbgl::style::DataDrivenPropertyValue<float> propertyValue = { 0xff };
         XCTAssertEqual(rawLayer->getCircleBlur(), propertyValue,
                        @"Setting circleBlur to a constant value should update circle-blur.");
-        XCTAssertEqualObjects(layer.circleBlur, styleValue,
+        XCTAssertEqualObjects(layer.circleBlur, constantStyleValue,
                               @"circleBlur should round-trip constant values.");
 
-        styleValue = [MGLStyleValue<NSNumber *> valueWithStops:@{
-            @18: styleValue,
-        }];
-        layer.circleBlur = styleValue;
-        propertyValue = { mbgl::style::Function<float> {
-            {{ 18, propertyValue.asConstant() }},
-            1,
-        }};
+        MGLStyleValue<NSNumber *> * functionStyleValue = [MGLStyleValue<NSNumber *> valueWithInterpolationMode:MGLInterpolationModeInterval cameraStops:@{@18: constantStyleValue} options:nil];
+        layer.circleBlur = functionStyleValue;
+
+        mbgl::style::IntervalStops<float> intervalStops = { {{18, 0xff}} };
+        propertyValue = mbgl::style::CameraFunction<float> { intervalStops };
+        
         XCTAssertEqual(rawLayer->getCircleBlur(), propertyValue,
-                       @"Setting circleBlur to a function should update circle-blur.");
-        XCTAssertEqualObjects(layer.circleBlur, styleValue,
-                              @"circleBlur should round-trip functions.");
+                       @"Setting circleBlur to a camera function should update circle-blur.");
+        XCTAssertEqualObjects(layer.circleBlur, functionStyleValue,
+                              @"circleBlur should round-trip camera functions.");
+
+        functionStyleValue = [MGLStyleValue<NSNumber *> valueWithInterpolationMode:MGLInterpolationModeExponential sourceStops:@{@18: constantStyleValue} attributeName:@"keyName" options:nil];
+        layer.circleBlur = functionStyleValue;
+
+        mbgl::style::ExponentialStops<float> exponentialStops = { {{18, 0xff}}, 1.0 };
+        propertyValue = mbgl::style::SourceFunction<float> { "keyName", exponentialStops };
+
+        XCTAssertEqual(rawLayer->getCircleBlur(), propertyValue,
+                       @"Setting circleBlur to a source function should update circle-blur.");
+        XCTAssertEqualObjects(layer.circleBlur, functionStyleValue,
+                              @"circleBlur should round-trip source functions.");
+
+        functionStyleValue = [MGLStyleValue<NSNumber *> valueWithInterpolationMode:MGLInterpolationModeExponential compositeStops:@{@10: @{@18: constantStyleValue}} attributeName:@"keyName" options:nil];
+        layer.circleBlur = functionStyleValue;
+
+        mbgl::style::ExponentialStops<float> innerStops = { { {18, 0xff}}, 1.0 };
+        std::map<float, mbgl::style::ExponentialStops<float>> compositeStops = { {10.0, innerStops} };
+
+        propertyValue = mbgl::style::CompositeFunction<float> { "keyName", compositeStops };
+
+        XCTAssertEqual(rawLayer->getCircleBlur(), propertyValue,
+                       @"Setting circleBlur to a composite function should update circle-blur.");
+        XCTAssertEqualObjects(layer.circleBlur, functionStyleValue,
+                              @"circleBlur should round-trip composite functions.");                                                                                                          
+                              
 
         layer.circleBlur = nil;
         XCTAssertTrue(rawLayer->getCircleBlur().isUndefined(),
@@ -83,26 +106,49 @@
                       @"circle-color should be unset initially.");
         MGLStyleValue<MGLColor *> *defaultStyleValue = layer.circleColor;
 
-        MGLStyleValue<MGLColor *> *styleValue = [MGLStyleValue<MGLColor *> valueWithRawValue:[MGLColor redColor]];
-        layer.circleColor = styleValue;
-        mbgl::style::PropertyValue<mbgl::Color> propertyValue = { { 1, 0, 0, 1 } };
+        MGLStyleValue<MGLColor *> *constantStyleValue = [MGLStyleValue<MGLColor *> valueWithRawValue:[MGLColor redColor]];
+        layer.circleColor = constantStyleValue;
+        mbgl::style::DataDrivenPropertyValue<mbgl::Color> propertyValue = { { 1, 0, 0, 1 } };
         XCTAssertEqual(rawLayer->getCircleColor(), propertyValue,
                        @"Setting circleColor to a constant value should update circle-color.");
-        XCTAssertEqualObjects(layer.circleColor, styleValue,
+        XCTAssertEqualObjects(layer.circleColor, constantStyleValue,
                               @"circleColor should round-trip constant values.");
 
-        styleValue = [MGLStyleValue<MGLColor *> valueWithStops:@{
-            @18: styleValue,
-        }];
-        layer.circleColor = styleValue;
-        propertyValue = { mbgl::style::Function<mbgl::Color> {
-            {{ 18, propertyValue.asConstant() }},
-            1,
-        }};
+        MGLStyleValue<MGLColor *> * functionStyleValue = [MGLStyleValue<MGLColor *> valueWithInterpolationMode:MGLInterpolationModeInterval cameraStops:@{@18: constantStyleValue} options:nil];
+        layer.circleColor = functionStyleValue;
+
+        mbgl::style::IntervalStops<mbgl::Color> intervalStops = { {{18, { 1, 0, 0, 1 }}} };
+        propertyValue = mbgl::style::CameraFunction<mbgl::Color> { intervalStops };
+        
         XCTAssertEqual(rawLayer->getCircleColor(), propertyValue,
-                       @"Setting circleColor to a function should update circle-color.");
-        XCTAssertEqualObjects(layer.circleColor, styleValue,
-                              @"circleColor should round-trip functions.");
+                       @"Setting circleColor to a camera function should update circle-color.");
+        XCTAssertEqualObjects(layer.circleColor, functionStyleValue,
+                              @"circleColor should round-trip camera functions.");
+
+        functionStyleValue = [MGLStyleValue<MGLColor *> valueWithInterpolationMode:MGLInterpolationModeExponential sourceStops:@{@18: constantStyleValue} attributeName:@"keyName" options:nil];
+        layer.circleColor = functionStyleValue;
+
+        mbgl::style::ExponentialStops<mbgl::Color> exponentialStops = { {{18, { 1, 0, 0, 1 }}}, 1.0 };
+        propertyValue = mbgl::style::SourceFunction<mbgl::Color> { "keyName", exponentialStops };
+
+        XCTAssertEqual(rawLayer->getCircleColor(), propertyValue,
+                       @"Setting circleColor to a source function should update circle-color.");
+        XCTAssertEqualObjects(layer.circleColor, functionStyleValue,
+                              @"circleColor should round-trip source functions.");
+
+        functionStyleValue = [MGLStyleValue<MGLColor *> valueWithInterpolationMode:MGLInterpolationModeExponential compositeStops:@{@10: @{@18: constantStyleValue}} attributeName:@"keyName" options:nil];
+        layer.circleColor = functionStyleValue;
+
+        mbgl::style::ExponentialStops<mbgl::Color> innerStops = { { {18, { 1, 0, 0, 1 }}}, 1.0 };
+        std::map<float, mbgl::style::ExponentialStops<mbgl::Color>> compositeStops = { {10.0, innerStops} };
+
+        propertyValue = mbgl::style::CompositeFunction<mbgl::Color> { "keyName", compositeStops };
+
+        XCTAssertEqual(rawLayer->getCircleColor(), propertyValue,
+                       @"Setting circleColor to a composite function should update circle-color.");
+        XCTAssertEqualObjects(layer.circleColor, functionStyleValue,
+                              @"circleColor should round-trip composite functions.");                                                                                                          
+                              
 
         layer.circleColor = nil;
         XCTAssertTrue(rawLayer->getCircleColor().isUndefined(),
@@ -117,26 +163,49 @@
                       @"circle-opacity should be unset initially.");
         MGLStyleValue<NSNumber *> *defaultStyleValue = layer.circleOpacity;
 
-        MGLStyleValue<NSNumber *> *styleValue = [MGLStyleValue<NSNumber *> valueWithRawValue:@0xff];
-        layer.circleOpacity = styleValue;
-        mbgl::style::PropertyValue<float> propertyValue = { 0xff };
+        MGLStyleValue<NSNumber *> *constantStyleValue = [MGLStyleValue<NSNumber *> valueWithRawValue:@0xff];
+        layer.circleOpacity = constantStyleValue;
+        mbgl::style::DataDrivenPropertyValue<float> propertyValue = { 0xff };
         XCTAssertEqual(rawLayer->getCircleOpacity(), propertyValue,
                        @"Setting circleOpacity to a constant value should update circle-opacity.");
-        XCTAssertEqualObjects(layer.circleOpacity, styleValue,
+        XCTAssertEqualObjects(layer.circleOpacity, constantStyleValue,
                               @"circleOpacity should round-trip constant values.");
 
-        styleValue = [MGLStyleValue<NSNumber *> valueWithStops:@{
-            @18: styleValue,
-        }];
-        layer.circleOpacity = styleValue;
-        propertyValue = { mbgl::style::Function<float> {
-            {{ 18, propertyValue.asConstant() }},
-            1,
-        }};
+        MGLStyleValue<NSNumber *> * functionStyleValue = [MGLStyleValue<NSNumber *> valueWithInterpolationMode:MGLInterpolationModeInterval cameraStops:@{@18: constantStyleValue} options:nil];
+        layer.circleOpacity = functionStyleValue;
+
+        mbgl::style::IntervalStops<float> intervalStops = { {{18, 0xff}} };
+        propertyValue = mbgl::style::CameraFunction<float> { intervalStops };
+        
         XCTAssertEqual(rawLayer->getCircleOpacity(), propertyValue,
-                       @"Setting circleOpacity to a function should update circle-opacity.");
-        XCTAssertEqualObjects(layer.circleOpacity, styleValue,
-                              @"circleOpacity should round-trip functions.");
+                       @"Setting circleOpacity to a camera function should update circle-opacity.");
+        XCTAssertEqualObjects(layer.circleOpacity, functionStyleValue,
+                              @"circleOpacity should round-trip camera functions.");
+
+        functionStyleValue = [MGLStyleValue<NSNumber *> valueWithInterpolationMode:MGLInterpolationModeExponential sourceStops:@{@18: constantStyleValue} attributeName:@"keyName" options:nil];
+        layer.circleOpacity = functionStyleValue;
+
+        mbgl::style::ExponentialStops<float> exponentialStops = { {{18, 0xff}}, 1.0 };
+        propertyValue = mbgl::style::SourceFunction<float> { "keyName", exponentialStops };
+
+        XCTAssertEqual(rawLayer->getCircleOpacity(), propertyValue,
+                       @"Setting circleOpacity to a source function should update circle-opacity.");
+        XCTAssertEqualObjects(layer.circleOpacity, functionStyleValue,
+                              @"circleOpacity should round-trip source functions.");
+
+        functionStyleValue = [MGLStyleValue<NSNumber *> valueWithInterpolationMode:MGLInterpolationModeExponential compositeStops:@{@10: @{@18: constantStyleValue}} attributeName:@"keyName" options:nil];
+        layer.circleOpacity = functionStyleValue;
+
+        mbgl::style::ExponentialStops<float> innerStops = { { {18, 0xff}}, 1.0 };
+        std::map<float, mbgl::style::ExponentialStops<float>> compositeStops = { {10.0, innerStops} };
+
+        propertyValue = mbgl::style::CompositeFunction<float> { "keyName", compositeStops };
+
+        XCTAssertEqual(rawLayer->getCircleOpacity(), propertyValue,
+                       @"Setting circleOpacity to a composite function should update circle-opacity.");
+        XCTAssertEqualObjects(layer.circleOpacity, functionStyleValue,
+                              @"circleOpacity should round-trip composite functions.");                                                                                                          
+                              
 
         layer.circleOpacity = nil;
         XCTAssertTrue(rawLayer->getCircleOpacity().isUndefined(),
@@ -151,26 +220,49 @@
                       @"circle-radius should be unset initially.");
         MGLStyleValue<NSNumber *> *defaultStyleValue = layer.circleRadius;
 
-        MGLStyleValue<NSNumber *> *styleValue = [MGLStyleValue<NSNumber *> valueWithRawValue:@0xff];
-        layer.circleRadius = styleValue;
-        mbgl::style::PropertyValue<float> propertyValue = { 0xff };
+        MGLStyleValue<NSNumber *> *constantStyleValue = [MGLStyleValue<NSNumber *> valueWithRawValue:@0xff];
+        layer.circleRadius = constantStyleValue;
+        mbgl::style::DataDrivenPropertyValue<float> propertyValue = { 0xff };
         XCTAssertEqual(rawLayer->getCircleRadius(), propertyValue,
                        @"Setting circleRadius to a constant value should update circle-radius.");
-        XCTAssertEqualObjects(layer.circleRadius, styleValue,
+        XCTAssertEqualObjects(layer.circleRadius, constantStyleValue,
                               @"circleRadius should round-trip constant values.");
 
-        styleValue = [MGLStyleValue<NSNumber *> valueWithStops:@{
-            @18: styleValue,
-        }];
-        layer.circleRadius = styleValue;
-        propertyValue = { mbgl::style::Function<float> {
-            {{ 18, propertyValue.asConstant() }},
-            1,
-        }};
+        MGLStyleValue<NSNumber *> * functionStyleValue = [MGLStyleValue<NSNumber *> valueWithInterpolationMode:MGLInterpolationModeInterval cameraStops:@{@18: constantStyleValue} options:nil];
+        layer.circleRadius = functionStyleValue;
+
+        mbgl::style::IntervalStops<float> intervalStops = { {{18, 0xff}} };
+        propertyValue = mbgl::style::CameraFunction<float> { intervalStops };
+        
         XCTAssertEqual(rawLayer->getCircleRadius(), propertyValue,
-                       @"Setting circleRadius to a function should update circle-radius.");
-        XCTAssertEqualObjects(layer.circleRadius, styleValue,
-                              @"circleRadius should round-trip functions.");
+                       @"Setting circleRadius to a camera function should update circle-radius.");
+        XCTAssertEqualObjects(layer.circleRadius, functionStyleValue,
+                              @"circleRadius should round-trip camera functions.");
+
+        functionStyleValue = [MGLStyleValue<NSNumber *> valueWithInterpolationMode:MGLInterpolationModeExponential sourceStops:@{@18: constantStyleValue} attributeName:@"keyName" options:nil];
+        layer.circleRadius = functionStyleValue;
+
+        mbgl::style::ExponentialStops<float> exponentialStops = { {{18, 0xff}}, 1.0 };
+        propertyValue = mbgl::style::SourceFunction<float> { "keyName", exponentialStops };
+
+        XCTAssertEqual(rawLayer->getCircleRadius(), propertyValue,
+                       @"Setting circleRadius to a source function should update circle-radius.");
+        XCTAssertEqualObjects(layer.circleRadius, functionStyleValue,
+                              @"circleRadius should round-trip source functions.");
+
+        functionStyleValue = [MGLStyleValue<NSNumber *> valueWithInterpolationMode:MGLInterpolationModeExponential compositeStops:@{@10: @{@18: constantStyleValue}} attributeName:@"keyName" options:nil];
+        layer.circleRadius = functionStyleValue;
+
+        mbgl::style::ExponentialStops<float> innerStops = { { {18, 0xff}}, 1.0 };
+        std::map<float, mbgl::style::ExponentialStops<float>> compositeStops = { {10.0, innerStops} };
+
+        propertyValue = mbgl::style::CompositeFunction<float> { "keyName", compositeStops };
+
+        XCTAssertEqual(rawLayer->getCircleRadius(), propertyValue,
+                       @"Setting circleRadius to a composite function should update circle-radius.");
+        XCTAssertEqualObjects(layer.circleRadius, functionStyleValue,
+                              @"circleRadius should round-trip composite functions.");                                                                                                          
+                              
 
         layer.circleRadius = nil;
         XCTAssertTrue(rawLayer->getCircleRadius().isUndefined(),
@@ -185,32 +277,38 @@
                       @"circle-pitch-scale should be unset initially.");
         MGLStyleValue<NSValue *> *defaultStyleValue = layer.circleScaleAlignment;
 
-        MGLStyleValue<NSValue *> *styleValue = [MGLStyleValue<NSValue *> valueWithRawValue:[NSValue valueWithMGLCircleScaleAlignment:MGLCircleScaleAlignmentViewport]];
-        layer.circleScaleAlignment = styleValue;
+        MGLStyleValue<NSValue *> *constantStyleValue = [MGLStyleValue<NSValue *> valueWithRawValue:[NSValue valueWithMGLCircleScaleAlignment:MGLCircleScaleAlignmentViewport]];
+        layer.circleScaleAlignment = constantStyleValue;
         mbgl::style::PropertyValue<mbgl::style::CirclePitchScaleType> propertyValue = { mbgl::style::CirclePitchScaleType::Viewport };
         XCTAssertEqual(rawLayer->getCirclePitchScale(), propertyValue,
                        @"Setting circleScaleAlignment to a constant value should update circle-pitch-scale.");
-        XCTAssertEqualObjects(layer.circleScaleAlignment, styleValue,
+        XCTAssertEqualObjects(layer.circleScaleAlignment, constantStyleValue,
                               @"circleScaleAlignment should round-trip constant values.");
 
-        styleValue = [MGLStyleValue<NSValue *> valueWithStops:@{
-            @18: styleValue,
-        }];
-        layer.circleScaleAlignment = styleValue;
-        propertyValue = { mbgl::style::Function<mbgl::style::CirclePitchScaleType> {
-            {{ 18, propertyValue.asConstant() }},
-            1,
-        }};
+        MGLStyleValue<NSValue *> * functionStyleValue = [MGLStyleValue<NSValue *> valueWithInterpolationMode:MGLInterpolationModeInterval cameraStops:@{@18: constantStyleValue} options:nil];
+        layer.circleScaleAlignment = functionStyleValue;
+
+        mbgl::style::IntervalStops<mbgl::style::CirclePitchScaleType> intervalStops = { {{18, mbgl::style::CirclePitchScaleType::Viewport}} };
+        propertyValue = mbgl::style::CameraFunction<mbgl::style::CirclePitchScaleType> { intervalStops };
+        
         XCTAssertEqual(rawLayer->getCirclePitchScale(), propertyValue,
-                       @"Setting circleScaleAlignment to a function should update circle-pitch-scale.");
-        XCTAssertEqualObjects(layer.circleScaleAlignment, styleValue,
-                              @"circleScaleAlignment should round-trip functions.");
+                       @"Setting circleScaleAlignment to a camera function should update circle-pitch-scale.");
+        XCTAssertEqualObjects(layer.circleScaleAlignment, functionStyleValue,
+                              @"circleScaleAlignment should round-trip camera functions.");
+
+                              
 
         layer.circleScaleAlignment = nil;
         XCTAssertTrue(rawLayer->getCirclePitchScale().isUndefined(),
                       @"Unsetting circleScaleAlignment should return circle-pitch-scale to the default value.");
         XCTAssertEqualObjects(layer.circleScaleAlignment, defaultStyleValue,
                               @"circleScaleAlignment should return the default value after being unset.");
+
+        functionStyleValue = [MGLStyleValue<NSValue *> valueWithInterpolationMode:MGLInterpolationModeIdentity sourceStops:nil attributeName:@"" options:nil];
+        XCTAssertThrowsSpecificNamed(layer.circleScaleAlignment = functionStyleValue, NSException, NSInvalidArgumentException, @"MGLStyleValue should raise an exception if it is applied to a property that cannot support it");
+
+        functionStyleValue = [MGLStyleValue<NSValue *> valueWithInterpolationMode:MGLInterpolationModeInterval compositeStops:@{@18: constantStyleValue} attributeName:@"" options:nil];
+        XCTAssertThrowsSpecificNamed(layer.circleScaleAlignment = functionStyleValue, NSException, NSInvalidArgumentException, @"MGLStyleValue should raise an exception if it is applied to a property that cannot support it");        
     }
 
     // circle-stroke-color
@@ -219,26 +317,49 @@
                       @"circle-stroke-color should be unset initially.");
         MGLStyleValue<MGLColor *> *defaultStyleValue = layer.circleStrokeColor;
 
-        MGLStyleValue<MGLColor *> *styleValue = [MGLStyleValue<MGLColor *> valueWithRawValue:[MGLColor redColor]];
-        layer.circleStrokeColor = styleValue;
-        mbgl::style::PropertyValue<mbgl::Color> propertyValue = { { 1, 0, 0, 1 } };
+        MGLStyleValue<MGLColor *> *constantStyleValue = [MGLStyleValue<MGLColor *> valueWithRawValue:[MGLColor redColor]];
+        layer.circleStrokeColor = constantStyleValue;
+        mbgl::style::DataDrivenPropertyValue<mbgl::Color> propertyValue = { { 1, 0, 0, 1 } };
         XCTAssertEqual(rawLayer->getCircleStrokeColor(), propertyValue,
                        @"Setting circleStrokeColor to a constant value should update circle-stroke-color.");
-        XCTAssertEqualObjects(layer.circleStrokeColor, styleValue,
+        XCTAssertEqualObjects(layer.circleStrokeColor, constantStyleValue,
                               @"circleStrokeColor should round-trip constant values.");
 
-        styleValue = [MGLStyleValue<MGLColor *> valueWithStops:@{
-            @18: styleValue,
-        }];
-        layer.circleStrokeColor = styleValue;
-        propertyValue = { mbgl::style::Function<mbgl::Color> {
-            {{ 18, propertyValue.asConstant() }},
-            1,
-        }};
+        MGLStyleValue<MGLColor *> * functionStyleValue = [MGLStyleValue<MGLColor *> valueWithInterpolationMode:MGLInterpolationModeInterval cameraStops:@{@18: constantStyleValue} options:nil];
+        layer.circleStrokeColor = functionStyleValue;
+
+        mbgl::style::IntervalStops<mbgl::Color> intervalStops = { {{18, { 1, 0, 0, 1 }}} };
+        propertyValue = mbgl::style::CameraFunction<mbgl::Color> { intervalStops };
+        
         XCTAssertEqual(rawLayer->getCircleStrokeColor(), propertyValue,
-                       @"Setting circleStrokeColor to a function should update circle-stroke-color.");
-        XCTAssertEqualObjects(layer.circleStrokeColor, styleValue,
-                              @"circleStrokeColor should round-trip functions.");
+                       @"Setting circleStrokeColor to a camera function should update circle-stroke-color.");
+        XCTAssertEqualObjects(layer.circleStrokeColor, functionStyleValue,
+                              @"circleStrokeColor should round-trip camera functions.");
+
+        functionStyleValue = [MGLStyleValue<MGLColor *> valueWithInterpolationMode:MGLInterpolationModeExponential sourceStops:@{@18: constantStyleValue} attributeName:@"keyName" options:nil];
+        layer.circleStrokeColor = functionStyleValue;
+
+        mbgl::style::ExponentialStops<mbgl::Color> exponentialStops = { {{18, { 1, 0, 0, 1 }}}, 1.0 };
+        propertyValue = mbgl::style::SourceFunction<mbgl::Color> { "keyName", exponentialStops };
+
+        XCTAssertEqual(rawLayer->getCircleStrokeColor(), propertyValue,
+                       @"Setting circleStrokeColor to a source function should update circle-stroke-color.");
+        XCTAssertEqualObjects(layer.circleStrokeColor, functionStyleValue,
+                              @"circleStrokeColor should round-trip source functions.");
+
+        functionStyleValue = [MGLStyleValue<MGLColor *> valueWithInterpolationMode:MGLInterpolationModeExponential compositeStops:@{@10: @{@18: constantStyleValue}} attributeName:@"keyName" options:nil];
+        layer.circleStrokeColor = functionStyleValue;
+
+        mbgl::style::ExponentialStops<mbgl::Color> innerStops = { { {18, { 1, 0, 0, 1 }}}, 1.0 };
+        std::map<float, mbgl::style::ExponentialStops<mbgl::Color>> compositeStops = { {10.0, innerStops} };
+
+        propertyValue = mbgl::style::CompositeFunction<mbgl::Color> { "keyName", compositeStops };
+
+        XCTAssertEqual(rawLayer->getCircleStrokeColor(), propertyValue,
+                       @"Setting circleStrokeColor to a composite function should update circle-stroke-color.");
+        XCTAssertEqualObjects(layer.circleStrokeColor, functionStyleValue,
+                              @"circleStrokeColor should round-trip composite functions.");                                                                                                          
+                              
 
         layer.circleStrokeColor = nil;
         XCTAssertTrue(rawLayer->getCircleStrokeColor().isUndefined(),
@@ -253,26 +374,49 @@
                       @"circle-stroke-opacity should be unset initially.");
         MGLStyleValue<NSNumber *> *defaultStyleValue = layer.circleStrokeOpacity;
 
-        MGLStyleValue<NSNumber *> *styleValue = [MGLStyleValue<NSNumber *> valueWithRawValue:@0xff];
-        layer.circleStrokeOpacity = styleValue;
-        mbgl::style::PropertyValue<float> propertyValue = { 0xff };
+        MGLStyleValue<NSNumber *> *constantStyleValue = [MGLStyleValue<NSNumber *> valueWithRawValue:@0xff];
+        layer.circleStrokeOpacity = constantStyleValue;
+        mbgl::style::DataDrivenPropertyValue<float> propertyValue = { 0xff };
         XCTAssertEqual(rawLayer->getCircleStrokeOpacity(), propertyValue,
                        @"Setting circleStrokeOpacity to a constant value should update circle-stroke-opacity.");
-        XCTAssertEqualObjects(layer.circleStrokeOpacity, styleValue,
+        XCTAssertEqualObjects(layer.circleStrokeOpacity, constantStyleValue,
                               @"circleStrokeOpacity should round-trip constant values.");
 
-        styleValue = [MGLStyleValue<NSNumber *> valueWithStops:@{
-            @18: styleValue,
-        }];
-        layer.circleStrokeOpacity = styleValue;
-        propertyValue = { mbgl::style::Function<float> {
-            {{ 18, propertyValue.asConstant() }},
-            1,
-        }};
+        MGLStyleValue<NSNumber *> * functionStyleValue = [MGLStyleValue<NSNumber *> valueWithInterpolationMode:MGLInterpolationModeInterval cameraStops:@{@18: constantStyleValue} options:nil];
+        layer.circleStrokeOpacity = functionStyleValue;
+
+        mbgl::style::IntervalStops<float> intervalStops = { {{18, 0xff}} };
+        propertyValue = mbgl::style::CameraFunction<float> { intervalStops };
+        
         XCTAssertEqual(rawLayer->getCircleStrokeOpacity(), propertyValue,
-                       @"Setting circleStrokeOpacity to a function should update circle-stroke-opacity.");
-        XCTAssertEqualObjects(layer.circleStrokeOpacity, styleValue,
-                              @"circleStrokeOpacity should round-trip functions.");
+                       @"Setting circleStrokeOpacity to a camera function should update circle-stroke-opacity.");
+        XCTAssertEqualObjects(layer.circleStrokeOpacity, functionStyleValue,
+                              @"circleStrokeOpacity should round-trip camera functions.");
+
+        functionStyleValue = [MGLStyleValue<NSNumber *> valueWithInterpolationMode:MGLInterpolationModeExponential sourceStops:@{@18: constantStyleValue} attributeName:@"keyName" options:nil];
+        layer.circleStrokeOpacity = functionStyleValue;
+
+        mbgl::style::ExponentialStops<float> exponentialStops = { {{18, 0xff}}, 1.0 };
+        propertyValue = mbgl::style::SourceFunction<float> { "keyName", exponentialStops };
+
+        XCTAssertEqual(rawLayer->getCircleStrokeOpacity(), propertyValue,
+                       @"Setting circleStrokeOpacity to a source function should update circle-stroke-opacity.");
+        XCTAssertEqualObjects(layer.circleStrokeOpacity, functionStyleValue,
+                              @"circleStrokeOpacity should round-trip source functions.");
+
+        functionStyleValue = [MGLStyleValue<NSNumber *> valueWithInterpolationMode:MGLInterpolationModeExponential compositeStops:@{@10: @{@18: constantStyleValue}} attributeName:@"keyName" options:nil];
+        layer.circleStrokeOpacity = functionStyleValue;
+
+        mbgl::style::ExponentialStops<float> innerStops = { { {18, 0xff}}, 1.0 };
+        std::map<float, mbgl::style::ExponentialStops<float>> compositeStops = { {10.0, innerStops} };
+
+        propertyValue = mbgl::style::CompositeFunction<float> { "keyName", compositeStops };
+
+        XCTAssertEqual(rawLayer->getCircleStrokeOpacity(), propertyValue,
+                       @"Setting circleStrokeOpacity to a composite function should update circle-stroke-opacity.");
+        XCTAssertEqualObjects(layer.circleStrokeOpacity, functionStyleValue,
+                              @"circleStrokeOpacity should round-trip composite functions.");                                                                                                          
+                              
 
         layer.circleStrokeOpacity = nil;
         XCTAssertTrue(rawLayer->getCircleStrokeOpacity().isUndefined(),
@@ -287,26 +431,49 @@
                       @"circle-stroke-width should be unset initially.");
         MGLStyleValue<NSNumber *> *defaultStyleValue = layer.circleStrokeWidth;
 
-        MGLStyleValue<NSNumber *> *styleValue = [MGLStyleValue<NSNumber *> valueWithRawValue:@0xff];
-        layer.circleStrokeWidth = styleValue;
-        mbgl::style::PropertyValue<float> propertyValue = { 0xff };
+        MGLStyleValue<NSNumber *> *constantStyleValue = [MGLStyleValue<NSNumber *> valueWithRawValue:@0xff];
+        layer.circleStrokeWidth = constantStyleValue;
+        mbgl::style::DataDrivenPropertyValue<float> propertyValue = { 0xff };
         XCTAssertEqual(rawLayer->getCircleStrokeWidth(), propertyValue,
                        @"Setting circleStrokeWidth to a constant value should update circle-stroke-width.");
-        XCTAssertEqualObjects(layer.circleStrokeWidth, styleValue,
+        XCTAssertEqualObjects(layer.circleStrokeWidth, constantStyleValue,
                               @"circleStrokeWidth should round-trip constant values.");
 
-        styleValue = [MGLStyleValue<NSNumber *> valueWithStops:@{
-            @18: styleValue,
-        }];
-        layer.circleStrokeWidth = styleValue;
-        propertyValue = { mbgl::style::Function<float> {
-            {{ 18, propertyValue.asConstant() }},
-            1,
-        }};
+        MGLStyleValue<NSNumber *> * functionStyleValue = [MGLStyleValue<NSNumber *> valueWithInterpolationMode:MGLInterpolationModeInterval cameraStops:@{@18: constantStyleValue} options:nil];
+        layer.circleStrokeWidth = functionStyleValue;
+
+        mbgl::style::IntervalStops<float> intervalStops = { {{18, 0xff}} };
+        propertyValue = mbgl::style::CameraFunction<float> { intervalStops };
+        
         XCTAssertEqual(rawLayer->getCircleStrokeWidth(), propertyValue,
-                       @"Setting circleStrokeWidth to a function should update circle-stroke-width.");
-        XCTAssertEqualObjects(layer.circleStrokeWidth, styleValue,
-                              @"circleStrokeWidth should round-trip functions.");
+                       @"Setting circleStrokeWidth to a camera function should update circle-stroke-width.");
+        XCTAssertEqualObjects(layer.circleStrokeWidth, functionStyleValue,
+                              @"circleStrokeWidth should round-trip camera functions.");
+
+        functionStyleValue = [MGLStyleValue<NSNumber *> valueWithInterpolationMode:MGLInterpolationModeExponential sourceStops:@{@18: constantStyleValue} attributeName:@"keyName" options:nil];
+        layer.circleStrokeWidth = functionStyleValue;
+
+        mbgl::style::ExponentialStops<float> exponentialStops = { {{18, 0xff}}, 1.0 };
+        propertyValue = mbgl::style::SourceFunction<float> { "keyName", exponentialStops };
+
+        XCTAssertEqual(rawLayer->getCircleStrokeWidth(), propertyValue,
+                       @"Setting circleStrokeWidth to a source function should update circle-stroke-width.");
+        XCTAssertEqualObjects(layer.circleStrokeWidth, functionStyleValue,
+                              @"circleStrokeWidth should round-trip source functions.");
+
+        functionStyleValue = [MGLStyleValue<NSNumber *> valueWithInterpolationMode:MGLInterpolationModeExponential compositeStops:@{@10: @{@18: constantStyleValue}} attributeName:@"keyName" options:nil];
+        layer.circleStrokeWidth = functionStyleValue;
+
+        mbgl::style::ExponentialStops<float> innerStops = { { {18, 0xff}}, 1.0 };
+        std::map<float, mbgl::style::ExponentialStops<float>> compositeStops = { {10.0, innerStops} };
+
+        propertyValue = mbgl::style::CompositeFunction<float> { "keyName", compositeStops };
+
+        XCTAssertEqual(rawLayer->getCircleStrokeWidth(), propertyValue,
+                       @"Setting circleStrokeWidth to a composite function should update circle-stroke-width.");
+        XCTAssertEqualObjects(layer.circleStrokeWidth, functionStyleValue,
+                              @"circleStrokeWidth should round-trip composite functions.");                                                                                                          
+                              
 
         layer.circleStrokeWidth = nil;
         XCTAssertTrue(rawLayer->getCircleStrokeWidth().isUndefined(),
@@ -321,32 +488,32 @@
                       @"circle-translate should be unset initially.");
         MGLStyleValue<NSValue *> *defaultStyleValue = layer.circleTranslation;
 
-        MGLStyleValue<NSValue *> *styleValue = [MGLStyleValue<NSValue *> valueWithRawValue:
+        MGLStyleValue<NSValue *> *constantStyleValue = [MGLStyleValue<NSValue *> valueWithRawValue:
 #if TARGET_OS_IPHONE
             [NSValue valueWithCGVector:CGVectorMake(1, 1)]
 #else
             [NSValue valueWithMGLVector:CGVectorMake(1, -1)]
 #endif
         ];
-        layer.circleTranslation = styleValue;
+        layer.circleTranslation = constantStyleValue;
         mbgl::style::PropertyValue<std::array<float, 2>> propertyValue = { { 1, 1 } };
         XCTAssertEqual(rawLayer->getCircleTranslate(), propertyValue,
                        @"Setting circleTranslation to a constant value should update circle-translate.");
-        XCTAssertEqualObjects(layer.circleTranslation, styleValue,
+        XCTAssertEqualObjects(layer.circleTranslation, constantStyleValue,
                               @"circleTranslation should round-trip constant values.");
 
-        styleValue = [MGLStyleValue<NSValue *> valueWithStops:@{
-            @18: styleValue,
-        }];
-        layer.circleTranslation = styleValue;
-        propertyValue = { mbgl::style::Function<std::array<float, 2>> {
-            {{ 18, propertyValue.asConstant() }},
-            1,
-        }};
+        MGLStyleValue<NSValue *> * functionStyleValue = [MGLStyleValue<NSValue *> valueWithInterpolationMode:MGLInterpolationModeInterval cameraStops:@{@18: constantStyleValue} options:nil];
+        layer.circleTranslation = functionStyleValue;
+
+        mbgl::style::IntervalStops<std::array<float, 2>> intervalStops = { {{18, { 1, 1 }}} };
+        propertyValue = mbgl::style::CameraFunction<std::array<float, 2>> { intervalStops };
+        
         XCTAssertEqual(rawLayer->getCircleTranslate(), propertyValue,
-                       @"Setting circleTranslation to a function should update circle-translate.");
-        XCTAssertEqualObjects(layer.circleTranslation, styleValue,
-                              @"circleTranslation should round-trip functions.");
+                       @"Setting circleTranslation to a camera function should update circle-translate.");
+        XCTAssertEqualObjects(layer.circleTranslation, functionStyleValue,
+                              @"circleTranslation should round-trip camera functions.");
+
+                              
 
         layer.circleTranslation = nil;
         XCTAssertTrue(rawLayer->getCircleTranslate().isUndefined(),
@@ -361,32 +528,38 @@
                       @"circle-translate-anchor should be unset initially.");
         MGLStyleValue<NSValue *> *defaultStyleValue = layer.circleTranslationAnchor;
 
-        MGLStyleValue<NSValue *> *styleValue = [MGLStyleValue<NSValue *> valueWithRawValue:[NSValue valueWithMGLCircleTranslationAnchor:MGLCircleTranslationAnchorViewport]];
-        layer.circleTranslationAnchor = styleValue;
+        MGLStyleValue<NSValue *> *constantStyleValue = [MGLStyleValue<NSValue *> valueWithRawValue:[NSValue valueWithMGLCircleTranslationAnchor:MGLCircleTranslationAnchorViewport]];
+        layer.circleTranslationAnchor = constantStyleValue;
         mbgl::style::PropertyValue<mbgl::style::TranslateAnchorType> propertyValue = { mbgl::style::TranslateAnchorType::Viewport };
         XCTAssertEqual(rawLayer->getCircleTranslateAnchor(), propertyValue,
                        @"Setting circleTranslationAnchor to a constant value should update circle-translate-anchor.");
-        XCTAssertEqualObjects(layer.circleTranslationAnchor, styleValue,
+        XCTAssertEqualObjects(layer.circleTranslationAnchor, constantStyleValue,
                               @"circleTranslationAnchor should round-trip constant values.");
 
-        styleValue = [MGLStyleValue<NSValue *> valueWithStops:@{
-            @18: styleValue,
-        }];
-        layer.circleTranslationAnchor = styleValue;
-        propertyValue = { mbgl::style::Function<mbgl::style::TranslateAnchorType> {
-            {{ 18, propertyValue.asConstant() }},
-            1,
-        }};
+        MGLStyleValue<NSValue *> * functionStyleValue = [MGLStyleValue<NSValue *> valueWithInterpolationMode:MGLInterpolationModeInterval cameraStops:@{@18: constantStyleValue} options:nil];
+        layer.circleTranslationAnchor = functionStyleValue;
+
+        mbgl::style::IntervalStops<mbgl::style::TranslateAnchorType> intervalStops = { {{18, mbgl::style::TranslateAnchorType::Viewport}} };
+        propertyValue = mbgl::style::CameraFunction<mbgl::style::TranslateAnchorType> { intervalStops };
+        
         XCTAssertEqual(rawLayer->getCircleTranslateAnchor(), propertyValue,
-                       @"Setting circleTranslationAnchor to a function should update circle-translate-anchor.");
-        XCTAssertEqualObjects(layer.circleTranslationAnchor, styleValue,
-                              @"circleTranslationAnchor should round-trip functions.");
+                       @"Setting circleTranslationAnchor to a camera function should update circle-translate-anchor.");
+        XCTAssertEqualObjects(layer.circleTranslationAnchor, functionStyleValue,
+                              @"circleTranslationAnchor should round-trip camera functions.");
+
+                              
 
         layer.circleTranslationAnchor = nil;
         XCTAssertTrue(rawLayer->getCircleTranslateAnchor().isUndefined(),
                       @"Unsetting circleTranslationAnchor should return circle-translate-anchor to the default value.");
         XCTAssertEqualObjects(layer.circleTranslationAnchor, defaultStyleValue,
                               @"circleTranslationAnchor should return the default value after being unset.");
+
+        functionStyleValue = [MGLStyleValue<NSValue *> valueWithInterpolationMode:MGLInterpolationModeIdentity sourceStops:nil attributeName:@"" options:nil];
+        XCTAssertThrowsSpecificNamed(layer.circleTranslationAnchor = functionStyleValue, NSException, NSInvalidArgumentException, @"MGLStyleValue should raise an exception if it is applied to a property that cannot support it");
+
+        functionStyleValue = [MGLStyleValue<NSValue *> valueWithInterpolationMode:MGLInterpolationModeInterval compositeStops:@{@18: constantStyleValue} attributeName:@"" options:nil];
+        XCTAssertThrowsSpecificNamed(layer.circleTranslationAnchor = functionStyleValue, NSException, NSInvalidArgumentException, @"MGLStyleValue should raise an exception if it is applied to a property that cannot support it");        
     }
 }
 

platform/darwin/test/MGLFillStyleLayerTests.mm

@@ -1,5 +1,5 @@
 // This file is generated.
-// Edit platform/darwin/scripts/generate-style-code.js, then run `make style-code-darwin`.
+// Edit platform/darwin/scripts/generate-style-code.js, then run `make darwin-style-code`.
 
 #import "MGLStyleLayerTests.h"
 
@@ -49,32 +49,38 @@
                       @"fill-antialias should be unset initially.");
         MGLStyleValue<NSNumber *> *defaultStyleValue = layer.fillAntialiased;
 
-        MGLStyleValue<NSNumber *> *styleValue = [MGLStyleValue<NSNumber *> valueWithRawValue:@NO];
-        layer.fillAntialiased = styleValue;
+        MGLStyleValue<NSNumber *> *constantStyleValue = [MGLStyleValue<NSNumber *> valueWithRawValue:@NO];
+        layer.fillAntialiased = constantStyleValue;
         mbgl::style::PropertyValue<bool> propertyValue = { false };
         XCTAssertEqual(rawLayer->getFillAntialias(), propertyValue,
                        @"Setting fillAntialiased to a constant value should update fill-antialias.");
-        XCTAssertEqualObjects(layer.fillAntialiased, styleValue,
+        XCTAssertEqualObjects(layer.fillAntialiased, constantStyleValue,
                               @"fillAntialiased should round-trip constant values.");
 
-        styleValue = [MGLStyleValue<NSNumber *> valueWithStops:@{
-            @18: styleValue,
-        }];
-        layer.fillAntialiased = styleValue;
-        propertyValue = { mbgl::style::Function<bool> {
-            {{ 18, propertyValue.asConstant() }},
-            1,
-        }};
+        MGLStyleValue<NSNumber *> * functionStyleValue = [MGLStyleValue<NSNumber *> valueWithInterpolationMode:MGLInterpolationModeInterval cameraStops:@{@18: constantStyleValue} options:nil];
+        layer.fillAntialiased = functionStyleValue;
+
+        mbgl::style::IntervalStops<bool> intervalStops = { {{18, false}} };
+        propertyValue = mbgl::style::CameraFunction<bool> { intervalStops };
+        
         XCTAssertEqual(rawLayer->getFillAntialias(), propertyValue,
-                       @"Setting fillAntialiased to a function should update fill-antialias.");
-        XCTAssertEqualObjects(layer.fillAntialiased, styleValue,
-                              @"fillAntialiased should round-trip functions.");
+                       @"Setting fillAntialiased to a camera function should update fill-antialias.");
+        XCTAssertEqualObjects(layer.fillAntialiased, functionStyleValue,
+                              @"fillAntialiased should round-trip camera functions.");
+
+                              
 
         layer.fillAntialiased = nil;
         XCTAssertTrue(rawLayer->getFillAntialias().isUndefined(),
                       @"Unsetting fillAntialiased should return fill-antialias to the default value.");
         XCTAssertEqualObjects(layer.fillAntialiased, defaultStyleValue,
                               @"fillAntialiased should return the default value after being unset.");
+
+        functionStyleValue = [MGLStyleValue<NSNumber *> valueWithInterpolationMode:MGLInterpolationModeIdentity sourceStops:nil attributeName:@"" options:nil];
+        XCTAssertThrowsSpecificNamed(layer.fillAntialiased = functionStyleValue, NSException, NSInvalidArgumentException, @"MGLStyleValue should raise an exception if it is applied to a property that cannot support it");
+
+        functionStyleValue = [MGLStyleValue<NSNumber *> valueWithInterpolationMode:MGLInterpolationModeInterval compositeStops:@{@18: constantStyleValue} attributeName:@"" options:nil];
+        XCTAssertThrowsSpecificNamed(layer.fillAntialiased = functionStyleValue, NSException, NSInvalidArgumentException, @"MGLStyleValue should raise an exception if it is applied to a property that cannot support it");        
     }
 
     // fill-color
@@ -83,26 +89,49 @@
                       @"fill-color should be unset initially.");
         MGLStyleValue<MGLColor *> *defaultStyleValue = layer.fillColor;
 
-        MGLStyleValue<MGLColor *> *styleValue = [MGLStyleValue<MGLColor *> valueWithRawValue:[MGLColor redColor]];
-        layer.fillColor = styleValue;
-        mbgl::style::PropertyValue<mbgl::Color> propertyValue = { { 1, 0, 0, 1 } };
+        MGLStyleValue<MGLColor *> *constantStyleValue = [MGLStyleValue<MGLColor *> valueWithRawValue:[MGLColor redColor]];
+        layer.fillColor = constantStyleValue;
+        mbgl::style::DataDrivenPropertyValue<mbgl::Color> propertyValue = { { 1, 0, 0, 1 } };
         XCTAssertEqual(rawLayer->getFillColor(), propertyValue,
                        @"Setting fillColor to a constant value should update fill-color.");
-        XCTAssertEqualObjects(layer.fillColor, styleValue,
+        XCTAssertEqualObjects(layer.fillColor, constantStyleValue,
                               @"fillColor should round-trip constant values.");
 
-        styleValue = [MGLStyleValue<MGLColor *> valueWithStops:@{
-            @18: styleValue,
-        }];
-        layer.fillColor = styleValue;
-        propertyValue = { mbgl::style::Function<mbgl::Color> {
-            {{ 18, propertyValue.asConstant() }},
-            1,
-        }};
+        MGLStyleValue<MGLColor *> * functionStyleValue = [MGLStyleValue<MGLColor *> valueWithInterpolationMode:MGLInterpolationModeInterval cameraStops:@{@18: constantStyleValue} options:nil];
+        layer.fillColor = functionStyleValue;
+
+        mbgl::style::IntervalStops<mbgl::Color> intervalStops = { {{18, { 1, 0, 0, 1 }}} };
+        propertyValue = mbgl::style::CameraFunction<mbgl::Color> { intervalStops };
+        
         XCTAssertEqual(rawLayer->getFillColor(), propertyValue,
-                       @"Setting fillColor to a function should update fill-color.");
-        XCTAssertEqualObjects(layer.fillColor, styleValue,
-                              @"fillColor should round-trip functions.");
+                       @"Setting fillColor to a camera function should update fill-color.");
+        XCTAssertEqualObjects(layer.fillColor, functionStyleValue,
+                              @"fillColor should round-trip camera functions.");
+
+        functionStyleValue = [MGLStyleValue<MGLColor *> valueWithInterpolationMode:MGLInterpolationModeExponential sourceStops:@{@18: constantStyleValue} attributeName:@"keyName" options:nil];
+        layer.fillColor = functionStyleValue;
+
+        mbgl::style::ExponentialStops<mbgl::Color> exponentialStops = { {{18, { 1, 0, 0, 1 }}}, 1.0 };
+        propertyValue = mbgl::style::SourceFunction<mbgl::Color> { "keyName", exponentialStops };
+
+        XCTAssertEqual(rawLayer->getFillColor(), propertyValue,
+                       @"Setting fillColor to a source function should update fill-color.");
+        XCTAssertEqualObjects(layer.fillColor, functionStyleValue,
+                              @"fillColor should round-trip source functions.");
+
+        functionStyleValue = [MGLStyleValue<MGLColor *> valueWithInterpolationMode:MGLInterpolationModeExponential compositeStops:@{@10: @{@18: constantStyleValue}} attributeName:@"keyName" options:nil];
+        layer.fillColor = functionStyleValue;
+
+        mbgl::style::ExponentialStops<mbgl::Color> innerStops = { { {18, { 1, 0, 0, 1 }}}, 1.0 };
+        std::map<float, mbgl::style::ExponentialStops<mbgl::Color>> compositeStops = { {10.0, innerStops} };
+
+        propertyValue = mbgl::style::CompositeFunction<mbgl::Color> { "keyName", compositeStops };
+
+        XCTAssertEqual(rawLayer->getFillColor(), propertyValue,
+                       @"Setting fillColor to a composite function should update fill-color.");
+        XCTAssertEqualObjects(layer.fillColor, functionStyleValue,
+                              @"fillColor should round-trip composite functions.");                                                                                                          
+                              
 
         layer.fillColor = nil;
         XCTAssertTrue(rawLayer->getFillColor().isUndefined(),
@@ -117,26 +146,49 @@
                       @"fill-opacity should be unset initially.");
         MGLStyleValue<NSNumber *> *defaultStyleValue = layer.fillOpacity;
 
-        MGLStyleValue<NSNumber *> *styleValue = [MGLStyleValue<NSNumber *> valueWithRawValue:@0xff];
-        layer.fillOpacity = styleValue;
-        mbgl::style::PropertyValue<float> propertyValue = { 0xff };
+        MGLStyleValue<NSNumber *> *constantStyleValue = [MGLStyleValue<NSNumber *> valueWithRawValue:@0xff];
+        layer.fillOpacity = constantStyleValue;
+        mbgl::style::DataDrivenPropertyValue<float> propertyValue = { 0xff };
         XCTAssertEqual(rawLayer->getFillOpacity(), propertyValue,
                        @"Setting fillOpacity to a constant value should update fill-opacity.");
-        XCTAssertEqualObjects(layer.fillOpacity, styleValue,
+        XCTAssertEqualObjects(layer.fillOpacity, constantStyleValue,
                               @"fillOpacity should round-trip constant values.");
 
-        styleValue = [MGLStyleValue<NSNumber *> valueWithStops:@{
-            @18: styleValue,
-        }];
-        layer.fillOpacity = styleValue;
-        propertyValue = { mbgl::style::Function<float> {
-            {{ 18, propertyValue.asConstant() }},
-            1,
-        }};
+        MGLStyleValue<NSNumber *> * functionStyleValue = [MGLStyleValue<NSNumber *> valueWithInterpolationMode:MGLInterpolationModeInterval cameraStops:@{@18: constantStyleValue} options:nil];
+        layer.fillOpacity = functionStyleValue;
+
+        mbgl::style::IntervalStops<float> intervalStops = { {{18, 0xff}} };
+        propertyValue = mbgl::style::CameraFunction<float> { intervalStops };
+        
         XCTAssertEqual(rawLayer->getFillOpacity(), propertyValue,
-                       @"Setting fillOpacity to a function should update fill-opacity.");
-        XCTAssertEqualObjects(layer.fillOpacity, styleValue,
-                              @"fillOpacity should round-trip functions.");
+                       @"Setting fillOpacity to a camera function should update fill-opacity.");
+        XCTAssertEqualObjects(layer.fillOpacity, functionStyleValue,
+                              @"fillOpacity should round-trip camera functions.");
+
+        functionStyleValue = [MGLStyleValue<NSNumber *> valueWithInterpolationMode:MGLInterpolationModeExponential sourceStops:@{@18: constantStyleValue} attributeName:@"keyName" options:nil];
+        layer.fillOpacity = functionStyleValue;
+
+        mbgl::style::ExponentialStops<float> exponentialStops = { {{18, 0xff}}, 1.0 };
+        propertyValue = mbgl::style::SourceFunction<float> { "keyName", exponentialStops };
+
+        XCTAssertEqual(rawLayer->getFillOpacity(), propertyValue,
+                       @"Setting fillOpacity to a source function should update fill-opacity.");
+        XCTAssertEqualObjects(layer.fillOpacity, functionStyleValue,
+                              @"fillOpacity should round-trip source functions.");
+
+        functionStyleValue = [MGLStyleValue<NSNumber *> valueWithInterpolationMode:MGLInterpolationModeExponential compositeStops:@{@10: @{@18: constantStyleValue}} attributeName:@"keyName" options:nil];
+        layer.fillOpacity = functionStyleValue;
+
+        mbgl::style::ExponentialStops<float> innerStops = { { {18, 0xff}}, 1.0 };
+        std::map<float, mbgl::style::ExponentialStops<float>> compositeStops = { {10.0, innerStops} };
+
+        propertyValue = mbgl::style::CompositeFunction<float> { "keyName", compositeStops };
+
+        XCTAssertEqual(rawLayer->getFillOpacity(), propertyValue,
+                       @"Setting fillOpacity to a composite function should update fill-opacity.");
+        XCTAssertEqualObjects(layer.fillOpacity, functionStyleValue,
+                              @"fillOpacity should round-trip composite functions.");                                                                                                          
+                              
 
         layer.fillOpacity = nil;
         XCTAssertTrue(rawLayer->getFillOpacity().isUndefined(),
@@ -151,26 +203,49 @@
                       @"fill-outline-color should be unset initially.");
         MGLStyleValue<MGLColor *> *defaultStyleValue = layer.fillOutlineColor;
 
-        MGLStyleValue<MGLColor *> *styleValue = [MGLStyleValue<MGLColor *> valueWithRawValue:[MGLColor redColor]];
-        layer.fillOutlineColor = styleValue;
-        mbgl::style::PropertyValue<mbgl::Color> propertyValue = { { 1, 0, 0, 1 } };
+        MGLStyleValue<MGLColor *> *constantStyleValue = [MGLStyleValue<MGLColor *> valueWithRawValue:[MGLColor redColor]];
+        layer.fillOutlineColor = constantStyleValue;
+        mbgl::style::DataDrivenPropertyValue<mbgl::Color> propertyValue = { { 1, 0, 0, 1 } };
         XCTAssertEqual(rawLayer->getFillOutlineColor(), propertyValue,
                        @"Setting fillOutlineColor to a constant value should update fill-outline-color.");
-        XCTAssertEqualObjects(layer.fillOutlineColor, styleValue,
+        XCTAssertEqualObjects(layer.fillOutlineColor, constantStyleValue,
                               @"fillOutlineColor should round-trip constant values.");
 
-        styleValue = [MGLStyleValue<MGLColor *> valueWithStops:@{
-            @18: styleValue,
-        }];
-        layer.fillOutlineColor = styleValue;
-        propertyValue = { mbgl::style::Function<mbgl::Color> {
-            {{ 18, propertyValue.asConstant() }},
-            1,
-        }};
+        MGLStyleValue<MGLColor *> * functionStyleValue = [MGLStyleValue<MGLColor *> valueWithInterpolationMode:MGLInterpolationModeInterval cameraStops:@{@18: constantStyleValue} options:nil];
+        layer.fillOutlineColor = functionStyleValue;
+
+        mbgl::style::IntervalStops<mbgl::Color> intervalStops = { {{18, { 1, 0, 0, 1 }}} };
+        propertyValue = mbgl::style::CameraFunction<mbgl::Color> { intervalStops };
+        
         XCTAssertEqual(rawLayer->getFillOutlineColor(), propertyValue,
-                       @"Setting fillOutlineColor to a function should update fill-outline-color.");
-        XCTAssertEqualObjects(layer.fillOutlineColor, styleValue,
-                              @"fillOutlineColor should round-trip functions.");
+                       @"Setting fillOutlineColor to a camera function should update fill-outline-color.");
+        XCTAssertEqualObjects(layer.fillOutlineColor, functionStyleValue,
+                              @"fillOutlineColor should round-trip camera functions.");
+
+        functionStyleValue = [MGLStyleValue<MGLColor *> valueWithInterpolationMode:MGLInterpolationModeExponential sourceStops:@{@18: constantStyleValue} attributeName:@"keyName" options:nil];
+        layer.fillOutlineColor = functionStyleValue;
+
+        mbgl::style::ExponentialStops<mbgl::Color> exponentialStops = { {{18, { 1, 0, 0, 1 }}}, 1.0 };
+        propertyValue = mbgl::style::SourceFunction<mbgl::Color> { "keyName", exponentialStops };
+
+        XCTAssertEqual(rawLayer->getFillOutlineColor(), propertyValue,
+                       @"Setting fillOutlineColor to a source function should update fill-outline-color.");
+        XCTAssertEqualObjects(layer.fillOutlineColor, functionStyleValue,
+                              @"fillOutlineColor should round-trip source functions.");
+
+        functionStyleValue = [MGLStyleValue<MGLColor *> valueWithInterpolationMode:MGLInterpolationModeExponential compositeStops:@{@10: @{@18: constantStyleValue}} attributeName:@"keyName" options:nil];
+        layer.fillOutlineColor = functionStyleValue;
+
+        mbgl::style::ExponentialStops<mbgl::Color> innerStops = { { {18, { 1, 0, 0, 1 }}}, 1.0 };
+        std::map<float, mbgl::style::ExponentialStops<mbgl::Color>> compositeStops = { {10.0, innerStops} };
+
+        propertyValue = mbgl::style::CompositeFunction<mbgl::Color> { "keyName", compositeStops };
+
+        XCTAssertEqual(rawLayer->getFillOutlineColor(), propertyValue,
+                       @"Setting fillOutlineColor to a composite function should update fill-outline-color.");
+        XCTAssertEqualObjects(layer.fillOutlineColor, functionStyleValue,
+                              @"fillOutlineColor should round-trip composite functions.");                                                                                                          
+                              
 
         layer.fillOutlineColor = nil;
         XCTAssertTrue(rawLayer->getFillOutlineColor().isUndefined(),
@@ -185,32 +260,38 @@
                       @"fill-pattern should be unset initially.");
         MGLStyleValue<NSString *> *defaultStyleValue = layer.fillPattern;
 
-        MGLStyleValue<NSString *> *styleValue = [MGLStyleValue<NSString *> valueWithRawValue:@"Fill Pattern"];
-        layer.fillPattern = styleValue;
+        MGLStyleValue<NSString *> *constantStyleValue = [MGLStyleValue<NSString *> valueWithRawValue:@"Fill Pattern"];
+        layer.fillPattern = constantStyleValue;
         mbgl::style::PropertyValue<std::string> propertyValue = { "Fill Pattern" };
         XCTAssertEqual(rawLayer->getFillPattern(), propertyValue,
                        @"Setting fillPattern to a constant value should update fill-pattern.");
-        XCTAssertEqualObjects(layer.fillPattern, styleValue,
+        XCTAssertEqualObjects(layer.fillPattern, constantStyleValue,
                               @"fillPattern should round-trip constant values.");
 
-        styleValue = [MGLStyleValue<NSString *> valueWithStops:@{
-            @18: styleValue,
-        }];
-        layer.fillPattern = styleValue;
-        propertyValue = { mbgl::style::Function<std::string> {
-            {{ 18, propertyValue.asConstant() }},
-            1,
-        }};
+        MGLStyleValue<NSString *> * functionStyleValue = [MGLStyleValue<NSString *> valueWithInterpolationMode:MGLInterpolationModeInterval cameraStops:@{@18: constantStyleValue} options:nil];
+        layer.fillPattern = functionStyleValue;
+
+        mbgl::style::IntervalStops<std::string> intervalStops = { {{18, "Fill Pattern"}} };
+        propertyValue = mbgl::style::CameraFunction<std::string> { intervalStops };
+        
         XCTAssertEqual(rawLayer->getFillPattern(), propertyValue,
-                       @"Setting fillPattern to a function should update fill-pattern.");
-        XCTAssertEqualObjects(layer.fillPattern, styleValue,
-                              @"fillPattern should round-trip functions.");
+                       @"Setting fillPattern to a camera function should update fill-pattern.");
+        XCTAssertEqualObjects(layer.fillPattern, functionStyleValue,
+                              @"fillPattern should round-trip camera functions.");
+
+                              
 
         layer.fillPattern = nil;
         XCTAssertTrue(rawLayer->getFillPattern().isUndefined(),
                       @"Unsetting fillPattern should return fill-pattern to the default value.");
         XCTAssertEqualObjects(layer.fillPattern, defaultStyleValue,
                               @"fillPattern should return the default value after being unset.");
+
+        functionStyleValue = [MGLStyleValue<NSString *> valueWithInterpolationMode:MGLInterpolationModeIdentity sourceStops:nil attributeName:@"" options:nil];
+        XCTAssertThrowsSpecificNamed(layer.fillPattern = functionStyleValue, NSException, NSInvalidArgumentException, @"MGLStyleValue should raise an exception if it is applied to a property that cannot support it");
+
+        functionStyleValue = [MGLStyleValue<NSString *> valueWithInterpolationMode:MGLInterpolationModeInterval compositeStops:@{@18: constantStyleValue} attributeName:@"" options:nil];
+        XCTAssertThrowsSpecificNamed(layer.fillPattern = functionStyleValue, NSException, NSInvalidArgumentException, @"MGLStyleValue should raise an exception if it is applied to a property that cannot support it");        
     }
 
     // fill-translate
@@ -219,32 +300,32 @@
                       @"fill-translate should be unset initially.");
         MGLStyleValue<NSValue *> *defaultStyleValue = layer.fillTranslation;
 
-        MGLStyleValue<NSValue *> *styleValue = [MGLStyleValue<NSValue *> valueWithRawValue:
+        MGLStyleValue<NSValue *> *constantStyleValue = [MGLStyleValue<NSValue *> valueWithRawValue:
 #if TARGET_OS_IPHONE
             [NSValue valueWithCGVector:CGVectorMake(1, 1)]
 #else
             [NSValue valueWithMGLVector:CGVectorMake(1, -1)]
 #endif
         ];
-        layer.fillTranslation = styleValue;
+        layer.fillTranslation = constantStyleValue;
         mbgl::style::PropertyValue<std::array<float, 2>> propertyValue = { { 1, 1 } };
         XCTAssertEqual(rawLayer->getFillTranslate(), propertyValue,
                        @"Setting fillTranslation to a constant value should update fill-translate.");
-        XCTAssertEqualObjects(layer.fillTranslation, styleValue,
+        XCTAssertEqualObjects(layer.fillTranslation, constantStyleValue,
                               @"fillTranslation should round-trip constant values.");
 
-        styleValue = [MGLStyleValue<NSValue *> valueWithStops:@{
-            @18: styleValue,
-        }];
-        layer.fillTranslation = styleValue;
-        propertyValue = { mbgl::style::Function<std::array<float, 2>> {
-            {{ 18, propertyValue.asConstant() }},
-            1,
-        }};
+        MGLStyleValue<NSValue *> * functionStyleValue = [MGLStyleValue<NSValue *> valueWithInterpolationMode:MGLInterpolationModeInterval cameraStops:@{@18: constantStyleValue} options:nil];
+        layer.fillTranslation = functionStyleValue;
+
+        mbgl::style::IntervalStops<std::array<float, 2>> intervalStops = { {{18, { 1, 1 }}} };
+        propertyValue = mbgl::style::CameraFunction<std::array<float, 2>> { intervalStops };
+        
         XCTAssertEqual(rawLayer->getFillTranslate(), propertyValue,
-                       @"Setting fillTranslation to a function should update fill-translate.");
-        XCTAssertEqualObjects(layer.fillTranslation, styleValue,
-                              @"fillTranslation should round-trip functions.");
+                       @"Setting fillTranslation to a camera function should update fill-translate.");
+        XCTAssertEqualObjects(layer.fillTranslation, functionStyleValue,
+                              @"fillTranslation should round-trip camera functions.");
+
+                              
 
         layer.fillTranslation = nil;
         XCTAssertTrue(rawLayer->getFillTranslate().isUndefined(),
@@ -259,32 +340,38 @@
                       @"fill-translate-anchor should be unset initially.");
         MGLStyleValue<NSValue *> *defaultStyleValue = layer.fillTranslationAnchor;
 
-        MGLStyleValue<NSValue *> *styleValue = [MGLStyleValue<NSValue *> valueWithRawValue:[NSValue valueWithMGLFillTranslationAnchor:MGLFillTranslationAnchorViewport]];
-        layer.fillTranslationAnchor = styleValue;
+        MGLStyleValue<NSValue *> *constantStyleValue = [MGLStyleValue<NSValue *> valueWithRawValue:[NSValue valueWithMGLFillTranslationAnchor:MGLFillTranslationAnchorViewport]];
+        layer.fillTranslationAnchor = constantStyleValue;
         mbgl::style::PropertyValue<mbgl::style::TranslateAnchorType> propertyValue = { mbgl::style::TranslateAnchorType::Viewport };
         XCTAssertEqual(rawLayer->getFillTranslateAnchor(), propertyValue,
                        @"Setting fillTranslationAnchor to a constant value should update fill-translate-anchor.");
-        XCTAssertEqualObjects(layer.fillTranslationAnchor, styleValue,
+        XCTAssertEqualObjects(layer.fillTranslationAnchor, constantStyleValue,
                               @"fillTranslationAnchor should round-trip constant values.");
 
-        styleValue = [MGLStyleValue<NSValue *> valueWithStops:@{
-            @18: styleValue,
-        }];
-        layer.fillTranslationAnchor = styleValue;
-        propertyValue = { mbgl::style::Function<mbgl::style::TranslateAnchorType> {
-            {{ 18, propertyValue.asConstant() }},
-            1,
-        }};
+        MGLStyleValue<NSValue *> * functionStyleValue = [MGLStyleValue<NSValue *> valueWithInterpolationMode:MGLInterpolationModeInterval cameraStops:@{@18: constantStyleValue} options:nil];
+        layer.fillTranslationAnchor = functionStyleValue;
+
+        mbgl::style::IntervalStops<mbgl::style::TranslateAnchorType> intervalStops = { {{18, mbgl::style::TranslateAnchorType::Viewport}} };
+        propertyValue = mbgl::style::CameraFunction<mbgl::style::TranslateAnchorType> { intervalStops };
+        
         XCTAssertEqual(rawLayer->getFillTranslateAnchor(), propertyValue,
-                       @"Setting fillTranslationAnchor to a function should update fill-translate-anchor.");
-        XCTAssertEqualObjects(layer.fillTranslationAnchor, styleValue,
-                              @"fillTranslationAnchor should round-trip functions.");
+                       @"Setting fillTranslationAnchor to a camera function should update fill-translate-anchor.");
+        XCTAssertEqualObjects(layer.fillTranslationAnchor, functionStyleValue,
+                              @"fillTranslationAnchor should round-trip camera functions.");
+
+                              
 
         layer.fillTranslationAnchor = nil;
         XCTAssertTrue(rawLayer->getFillTranslateAnchor().isUndefined(),
                       @"Unsetting fillTranslationAnchor should return fill-translate-anchor to the default value.");
         XCTAssertEqualObjects(layer.fillTranslationAnchor, defaultStyleValue,
                               @"fillTranslationAnchor should return the default value after being unset.");
+
+        functionStyleValue = [MGLStyleValue<NSValue *> valueWithInterpolationMode:MGLInterpolationModeIdentity sourceStops:nil attributeName:@"" options:nil];
+        XCTAssertThrowsSpecificNamed(layer.fillTranslationAnchor = functionStyleValue, NSException, NSInvalidArgumentException, @"MGLStyleValue should raise an exception if it is applied to a property that cannot support it");
+
+        functionStyleValue = [MGLStyleValue<NSValue *> valueWithInterpolationMode:MGLInterpolationModeInterval compositeStops:@{@18: constantStyleValue} attributeName:@"" options:nil];
+        XCTAssertThrowsSpecificNamed(layer.fillTranslationAnchor = functionStyleValue, NSException, NSInvalidArgumentException, @"MGLStyleValue should raise an exception if it is applied to a property that cannot support it");        
     }
 }
 

platform/darwin/test/MGLLineStyleLayerTests.mm

@@ -1,5 +1,5 @@
 // This file is generated.
-// Edit platform/darwin/scripts/generate-style-code.js, then run `make style-code-darwin`.
+// Edit platform/darwin/scripts/generate-style-code.js, then run `make darwin-style-code`.
 
 #import "MGLStyleLayerTests.h"
 
@@ -49,32 +49,38 @@
                       @"line-cap should be unset initially.");
         MGLStyleValue<NSValue *> *defaultStyleValue = layer.lineCap;
 
-        MGLStyleValue<NSValue *> *styleValue = [MGLStyleValue<NSValue *> valueWithRawValue:[NSValue valueWithMGLLineCap:MGLLineCapSquare]];
-        layer.lineCap = styleValue;
+        MGLStyleValue<NSValue *> *constantStyleValue = [MGLStyleValue<NSValue *> valueWithRawValue:[NSValue valueWithMGLLineCap:MGLLineCapSquare]];
+        layer.lineCap = constantStyleValue;
         mbgl::style::PropertyValue<mbgl::style::LineCapType> propertyValue = { mbgl::style::LineCapType::Square };
         XCTAssertEqual(rawLayer->getLineCap(), propertyValue,
                        @"Setting lineCap to a constant value should update line-cap.");
-        XCTAssertEqualObjects(layer.lineCap, styleValue,
+        XCTAssertEqualObjects(layer.lineCap, constantStyleValue,
                               @"lineCap should round-trip constant values.");
 
-        styleValue = [MGLStyleValue<NSValue *> valueWithStops:@{
-            @18: styleValue,
-        }];
-        layer.lineCap = styleValue;
-        propertyValue = { mbgl::style::Function<mbgl::style::LineCapType> {
-            {{ 18, propertyValue.asConstant() }},
-            1,
-        }};
+        MGLStyleValue<NSValue *> * functionStyleValue = [MGLStyleValue<NSValue *> valueWithInterpolationMode:MGLInterpolationModeInterval cameraStops:@{@18: constantStyleValue} options:nil];
+        layer.lineCap = functionStyleValue;
+
+        mbgl::style::IntervalStops<mbgl::style::LineCapType> intervalStops = { {{18, mbgl::style::LineCapType::Square}} };
+        propertyValue = mbgl::style::CameraFunction<mbgl::style::LineCapType> { intervalStops };
+        
         XCTAssertEqual(rawLayer->getLineCap(), propertyValue,
-                       @"Setting lineCap to a function should update line-cap.");
-        XCTAssertEqualObjects(layer.lineCap, styleValue,
-                              @"lineCap should round-trip functions.");
+                       @"Setting lineCap to a camera function should update line-cap.");
+        XCTAssertEqualObjects(layer.lineCap, functionStyleValue,
+                              @"lineCap should round-trip camera functions.");
+
+                              
 
         layer.lineCap = nil;
         XCTAssertTrue(rawLayer->getLineCap().isUndefined(),
                       @"Unsetting lineCap should return line-cap to the default value.");
         XCTAssertEqualObjects(layer.lineCap, defaultStyleValue,
                               @"lineCap should return the default value after being unset.");
+
+        functionStyleValue = [MGLStyleValue<NSValue *> valueWithInterpolationMode:MGLInterpolationModeIdentity sourceStops:nil attributeName:@"" options:nil];
+        XCTAssertThrowsSpecificNamed(layer.lineCap = functionStyleValue, NSException, NSInvalidArgumentException, @"MGLStyleValue should raise an exception if it is applied to a property that cannot support it");
+
+        functionStyleValue = [MGLStyleValue<NSValue *> valueWithInterpolationMode:MGLInterpolationModeInterval compositeStops:@{@18: constantStyleValue} attributeName:@"" options:nil];
+        XCTAssertThrowsSpecificNamed(layer.lineCap = functionStyleValue, NSException, NSInvalidArgumentException, @"MGLStyleValue should raise an exception if it is applied to a property that cannot support it");        
     }
 
     // line-join
@@ -83,32 +89,38 @@
                       @"line-join should be unset initially.");
         MGLStyleValue<NSValue *> *defaultStyleValue = layer.lineJoin;
 
-        MGLStyleValue<NSValue *> *styleValue = [MGLStyleValue<NSValue *> valueWithRawValue:[NSValue valueWithMGLLineJoin:MGLLineJoinMiter]];
-        layer.lineJoin = styleValue;
+        MGLStyleValue<NSValue *> *constantStyleValue = [MGLStyleValue<NSValue *> valueWithRawValue:[NSValue valueWithMGLLineJoin:MGLLineJoinMiter]];
+        layer.lineJoin = constantStyleValue;
         mbgl::style::PropertyValue<mbgl::style::LineJoinType> propertyValue = { mbgl::style::LineJoinType::Miter };
         XCTAssertEqual(rawLayer->getLineJoin(), propertyValue,
                        @"Setting lineJoin to a constant value should update line-join.");
-        XCTAssertEqualObjects(layer.lineJoin, styleValue,
+        XCTAssertEqualObjects(layer.lineJoin, constantStyleValue,
                               @"lineJoin should round-trip constant values.");
 
-        styleValue = [MGLStyleValue<NSValue *> valueWithStops:@{
-            @18: styleValue,
-        }];
-        layer.lineJoin = styleValue;
-        propertyValue = { mbgl::style::Function<mbgl::style::LineJoinType> {
-            {{ 18, propertyValue.asConstant() }},
-            1,
-        }};
+        MGLStyleValue<NSValue *> * functionStyleValue = [MGLStyleValue<NSValue *> valueWithInterpolationMode:MGLInterpolationModeInterval cameraStops:@{@18: constantStyleValue} options:nil];
+        layer.lineJoin = functionStyleValue;
+
+        mbgl::style::IntervalStops<mbgl::style::LineJoinType> intervalStops = { {{18, mbgl::style::LineJoinType::Miter}} };
+        propertyValue = mbgl::style::CameraFunction<mbgl::style::LineJoinType> { intervalStops };
+        
         XCTAssertEqual(rawLayer->getLineJoin(), propertyValue,
-                       @"Setting lineJoin to a function should update line-join.");
-        XCTAssertEqualObjects(layer.lineJoin, styleValue,
-                              @"lineJoin should round-trip functions.");
+                       @"Setting lineJoin to a camera function should update line-join.");
+        XCTAssertEqualObjects(layer.lineJoin, functionStyleValue,
+                              @"lineJoin should round-trip camera functions.");
+
+                              
 
         layer.lineJoin = nil;
         XCTAssertTrue(rawLayer->getLineJoin().isUndefined(),
                       @"Unsetting lineJoin should return line-join to the default value.");
         XCTAssertEqualObjects(layer.lineJoin, defaultStyleValue,
                               @"lineJoin should return the default value after being unset.");
+
+        functionStyleValue = [MGLStyleValue<NSValue *> valueWithInterpolationMode:MGLInterpolationModeIdentity sourceStops:nil attributeName:@"" options:nil];
+        XCTAssertThrowsSpecificNamed(layer.lineJoin = functionStyleValue, NSException, NSInvalidArgumentException, @"MGLStyleValue should raise an exception if it is applied to a property that cannot support it");
+
+        functionStyleValue = [MGLStyleValue<NSValue *> valueWithInterpolationMode:MGLInterpolationModeInterval compositeStops:@{@18: constantStyleValue} attributeName:@"" options:nil];
+        XCTAssertThrowsSpecificNamed(layer.lineJoin = functionStyleValue, NSException, NSInvalidArgumentException, @"MGLStyleValue should raise an exception if it is applied to a property that cannot support it");        
     }
 
     // line-miter-limit
@@ -117,26 +129,26 @@
                       @"line-miter-limit should be unset initially.");
         MGLStyleValue<NSNumber *> *defaultStyleValue = layer.lineMiterLimit;
 
-        MGLStyleValue<NSNumber *> *styleValue = [MGLStyleValue<NSNumber *> valueWithRawValue:@0xff];
-        layer.lineMiterLimit = styleValue;
+        MGLStyleValue<NSNumber *> *constantStyleValue = [MGLStyleValue<NSNumber *> valueWithRawValue:@0xff];
+        layer.lineMiterLimit = constantStyleValue;
         mbgl::style::PropertyValue<float> propertyValue = { 0xff };
         XCTAssertEqual(rawLayer->getLineMiterLimit(), propertyValue,
                        @"Setting lineMiterLimit to a constant value should update line-miter-limit.");
-        XCTAssertEqualObjects(layer.lineMiterLimit, styleValue,
+        XCTAssertEqualObjects(layer.lineMiterLimit, constantStyleValue,
                               @"lineMiterLimit should round-trip constant values.");
 
-        styleValue = [MGLStyleValue<NSNumber *> valueWithStops:@{
-            @18: styleValue,
-        }];
-        layer.lineMiterLimit = styleValue;
-        propertyValue = { mbgl::style::Function<float> {
-            {{ 18, propertyValue.asConstant() }},
-            1,
-        }};
+        MGLStyleValue<NSNumber *> * functionStyleValue = [MGLStyleValue<NSNumber *> valueWithInterpolationMode:MGLInterpolationModeInterval cameraStops:@{@18: constantStyleValue} options:nil];
+        layer.lineMiterLimit = functionStyleValue;
+
+        mbgl::style::IntervalStops<float> intervalStops = { {{18, 0xff}} };
+        propertyValue = mbgl::style::CameraFunction<float> { intervalStops };
+        
         XCTAssertEqual(rawLayer->getLineMiterLimit(), propertyValue,
-                       @"Setting lineMiterLimit to a function should update line-miter-limit.");
-        XCTAssertEqualObjects(layer.lineMiterLimit, styleValue,
-                              @"lineMiterLimit should round-trip functions.");
+                       @"Setting lineMiterLimit to a camera function should update line-miter-limit.");
+        XCTAssertEqualObjects(layer.lineMiterLimit, functionStyleValue,
+                              @"lineMiterLimit should round-trip camera functions.");
+
+                              
 
         layer.lineMiterLimit = nil;
         XCTAssertTrue(rawLayer->getLineMiterLimit().isUndefined(),
@@ -151,26 +163,26 @@
                       @"line-round-limit should be unset initially.");
         MGLStyleValue<NSNumber *> *defaultStyleValue = layer.lineRoundLimit;
 
-        MGLStyleValue<NSNumber *> *styleValue = [MGLStyleValue<NSNumber *> valueWithRawValue:@0xff];
-        layer.lineRoundLimit = styleValue;
+        MGLStyleValue<NSNumber *> *constantStyleValue = [MGLStyleValue<NSNumber *> valueWithRawValue:@0xff];
+        layer.lineRoundLimit = constantStyleValue;
         mbgl::style::PropertyValue<float> propertyValue = { 0xff };
         XCTAssertEqual(rawLayer->getLineRoundLimit(), propertyValue,
                        @"Setting lineRoundLimit to a constant value should update line-round-limit.");
-        XCTAssertEqualObjects(layer.lineRoundLimit, styleValue,
+        XCTAssertEqualObjects(layer.lineRoundLimit, constantStyleValue,
                               @"lineRoundLimit should round-trip constant values.");
 
-        styleValue = [MGLStyleValue<NSNumber *> valueWithStops:@{
-            @18: styleValue,
-        }];
-        layer.lineRoundLimit = styleValue;
-        propertyValue = { mbgl::style::Function<float> {
-            {{ 18, propertyValue.asConstant() }},
-            1,
-        }};
+        MGLStyleValue<NSNumber *> * functionStyleValue = [MGLStyleValue<NSNumber *> valueWithInterpolationMode:MGLInterpolationModeInterval cameraStops:@{@18: constantStyleValue} options:nil];
+        layer.lineRoundLimit = functionStyleValue;
+
+        mbgl::style::IntervalStops<float> intervalStops = { {{18, 0xff}} };
+        propertyValue = mbgl::style::CameraFunction<float> { intervalStops };
+        
         XCTAssertEqual(rawLayer->getLineRoundLimit(), propertyValue,
-                       @"Setting lineRoundLimit to a function should update line-round-limit.");
-        XCTAssertEqualObjects(layer.lineRoundLimit, styleValue,
-                              @"lineRoundLimit should round-trip functions.");
+                       @"Setting lineRoundLimit to a camera function should update line-round-limit.");
+        XCTAssertEqualObjects(layer.lineRoundLimit, functionStyleValue,
+                              @"lineRoundLimit should round-trip camera functions.");
+
+                              
 
         layer.lineRoundLimit = nil;
         XCTAssertTrue(rawLayer->getLineRoundLimit().isUndefined(),
@@ -185,26 +197,49 @@
                       @"line-blur should be unset initially.");
         MGLStyleValue<NSNumber *> *defaultStyleValue = layer.lineBlur;
 
-        MGLStyleValue<NSNumber *> *styleValue = [MGLStyleValue<NSNumber *> valueWithRawValue:@0xff];
-        layer.lineBlur = styleValue;
-        mbgl::style::PropertyValue<float> propertyValue = { 0xff };
+        MGLStyleValue<NSNumber *> *constantStyleValue = [MGLStyleValue<NSNumber *> valueWithRawValue:@0xff];
+        layer.lineBlur = constantStyleValue;
+        mbgl::style::DataDrivenPropertyValue<float> propertyValue = { 0xff };
         XCTAssertEqual(rawLayer->getLineBlur(), propertyValue,
                        @"Setting lineBlur to a constant value should update line-blur.");
-        XCTAssertEqualObjects(layer.lineBlur, styleValue,
+        XCTAssertEqualObjects(layer.lineBlur, constantStyleValue,
                               @"lineBlur should round-trip constant values.");
 
-        styleValue = [MGLStyleValue<NSNumber *> valueWithStops:@{
-            @18: styleValue,
-        }];
-        layer.lineBlur = styleValue;
-        propertyValue = { mbgl::style::Function<float> {
-            {{ 18, propertyValue.asConstant() }},
-            1,
-        }};
+        MGLStyleValue<NSNumber *> * functionStyleValue = [MGLStyleValue<NSNumber *> valueWithInterpolationMode:MGLInterpolationModeInterval cameraStops:@{@18: constantStyleValue} options:nil];
+        layer.lineBlur = functionStyleValue;
+
+        mbgl::style::IntervalStops<float> intervalStops = { {{18, 0xff}} };
+        propertyValue = mbgl::style::CameraFunction<float> { intervalStops };
+        
         XCTAssertEqual(rawLayer->getLineBlur(), propertyValue,
-                       @"Setting lineBlur to a function should update line-blur.");
-        XCTAssertEqualObjects(layer.lineBlur, styleValue,
-                              @"lineBlur should round-trip functions.");
+                       @"Setting lineBlur to a camera function should update line-blur.");
+        XCTAssertEqualObjects(layer.lineBlur, functionStyleValue,
+                              @"lineBlur should round-trip camera functions.");
+
+        functionStyleValue = [MGLStyleValue<NSNumber *> valueWithInterpolationMode:MGLInterpolationModeExponential sourceStops:@{@18: constantStyleValue} attributeName:@"keyName" options:nil];
+        layer.lineBlur = functionStyleValue;
+
+        mbgl::style::ExponentialStops<float> exponentialStops = { {{18, 0xff}}, 1.0 };
+        propertyValue = mbgl::style::SourceFunction<float> { "keyName", exponentialStops };
+
+        XCTAssertEqual(rawLayer->getLineBlur(), propertyValue,
+                       @"Setting lineBlur to a source function should update line-blur.");
+        XCTAssertEqualObjects(layer.lineBlur, functionStyleValue,
+                              @"lineBlur should round-trip source functions.");
+
+        functionStyleValue = [MGLStyleValue<NSNumber *> valueWithInterpolationMode:MGLInterpolationModeExponential compositeStops:@{@10: @{@18: constantStyleValue}} attributeName:@"keyName" options:nil];
+        layer.lineBlur = functionStyleValue;
+
+        mbgl::style::ExponentialStops<float> innerStops = { { {18, 0xff}}, 1.0 };
+        std::map<float, mbgl::style::ExponentialStops<float>> compositeStops = { {10.0, innerStops} };
+
+        propertyValue = mbgl::style::CompositeFunction<float> { "keyName", compositeStops };
+
+        XCTAssertEqual(rawLayer->getLineBlur(), propertyValue,
+                       @"Setting lineBlur to a composite function should update line-blur.");
+        XCTAssertEqualObjects(layer.lineBlur, functionStyleValue,
+                              @"lineBlur should round-trip composite functions.");                                                                                                          
+                              
 
         layer.lineBlur = nil;
         XCTAssertTrue(rawLayer->getLineBlur().isUndefined(),
@@ -219,26 +254,49 @@
                       @"line-color should be unset initially.");
         MGLStyleValue<MGLColor *> *defaultStyleValue = layer.lineColor;
 
-        MGLStyleValue<MGLColor *> *styleValue = [MGLStyleValue<MGLColor *> valueWithRawValue:[MGLColor redColor]];
-        layer.lineColor = styleValue;
-        mbgl::style::PropertyValue<mbgl::Color> propertyValue = { { 1, 0, 0, 1 } };
+        MGLStyleValue<MGLColor *> *constantStyleValue = [MGLStyleValue<MGLColor *> valueWithRawValue:[MGLColor redColor]];
+        layer.lineColor = constantStyleValue;
+        mbgl::style::DataDrivenPropertyValue<mbgl::Color> propertyValue = { { 1, 0, 0, 1 } };
         XCTAssertEqual(rawLayer->getLineColor(), propertyValue,
                        @"Setting lineColor to a constant value should update line-color.");
-        XCTAssertEqualObjects(layer.lineColor, styleValue,
+        XCTAssertEqualObjects(layer.lineColor, constantStyleValue,
                               @"lineColor should round-trip constant values.");
 
-        styleValue = [MGLStyleValue<MGLColor *> valueWithStops:@{
-            @18: styleValue,
-        }];
-        layer.lineColor = styleValue;
-        propertyValue = { mbgl::style::Function<mbgl::Color> {
-            {{ 18, propertyValue.asConstant() }},
-            1,
-        }};
+        MGLStyleValue<MGLColor *> * functionStyleValue = [MGLStyleValue<MGLColor *> valueWithInterpolationMode:MGLInterpolationModeInterval cameraStops:@{@18: constantStyleValue} options:nil];
+        layer.lineColor = functionStyleValue;
+
+        mbgl::style::IntervalStops<mbgl::Color> intervalStops = { {{18, { 1, 0, 0, 1 }}} };
+        propertyValue = mbgl::style::CameraFunction<mbgl::Color> { intervalStops };
+        
         XCTAssertEqual(rawLayer->getLineColor(), propertyValue,
-                       @"Setting lineColor to a function should update line-color.");
-        XCTAssertEqualObjects(layer.lineColor, styleValue,
-                              @"lineColor should round-trip functions.");
+                       @"Setting lineColor to a camera function should update line-color.");
+        XCTAssertEqualObjects(layer.lineColor, functionStyleValue,
+                              @"lineColor should round-trip camera functions.");
+
+        functionStyleValue = [MGLStyleValue<MGLColor *> valueWithInterpolationMode:MGLInterpolationModeExponential sourceStops:@{@18: constantStyleValue} attributeName:@"keyName" options:nil];
+        layer.lineColor = functionStyleValue;
+
+        mbgl::style::ExponentialStops<mbgl::Color> exponentialStops = { {{18, { 1, 0, 0, 1 }}}, 1.0 };
+        propertyValue = mbgl::style::SourceFunction<mbgl::Color> { "keyName", exponentialStops };
+
+        XCTAssertEqual(rawLayer->getLineColor(), propertyValue,
+                       @"Setting lineColor to a source function should update line-color.");
+        XCTAssertEqualObjects(layer.lineColor, functionStyleValue,
+                              @"lineColor should round-trip source functions.");
+
+        functionStyleValue = [MGLStyleValue<MGLColor *> valueWithInterpolationMode:MGLInterpolationModeExponential compositeStops:@{@10: @{@18: constantStyleValue}} attributeName:@"keyName" options:nil];
+        layer.lineColor = functionStyleValue;
+
+        mbgl::style::ExponentialStops<mbgl::Color> innerStops = { { {18, { 1, 0, 0, 1 }}}, 1.0 };
+        std::map<float, mbgl::style::ExponentialStops<mbgl::Color>> compositeStops = { {10.0, innerStops} };
+
+        propertyValue = mbgl::style::CompositeFunction<mbgl::Color> { "keyName", compositeStops };
+
+        XCTAssertEqual(rawLayer->getLineColor(), propertyValue,
+                       @"Setting lineColor to a composite function should update line-color.");
+        XCTAssertEqualObjects(layer.lineColor, functionStyleValue,
+                              @"lineColor should round-trip composite functions.");                                                                                                          
+                              
 
         layer.lineColor = nil;
         XCTAssertTrue(rawLayer->getLineColor().isUndefined(),
@@ -253,32 +311,38 @@
                       @"line-dasharray should be unset initially.");
         MGLStyleValue<NSArray<NSNumber *> *> *defaultStyleValue = layer.lineDashPattern;
 
-        MGLStyleValue<NSArray<NSNumber *> *> *styleValue = [MGLStyleValue<NSArray<NSNumber *> *> valueWithRawValue:@[@1, @2]];
-        layer.lineDashPattern = styleValue;
+        MGLStyleValue<NSArray<NSNumber *> *> *constantStyleValue = [MGLStyleValue<NSArray<NSNumber *> *> valueWithRawValue:@[@1, @2]];
+        layer.lineDashPattern = constantStyleValue;
         mbgl::style::PropertyValue<std::vector<float>> propertyValue = { {1, 2} };
         XCTAssertEqual(rawLayer->getLineDasharray(), propertyValue,
                        @"Setting lineDashPattern to a constant value should update line-dasharray.");
-        XCTAssertEqualObjects(layer.lineDashPattern, styleValue,
+        XCTAssertEqualObjects(layer.lineDashPattern, constantStyleValue,
                               @"lineDashPattern should round-trip constant values.");
 
-        styleValue = [MGLStyleValue<NSArray<NSNumber *> *> valueWithStops:@{
-            @18: styleValue,
-        }];
-        layer.lineDashPattern = styleValue;
-        propertyValue = { mbgl::style::Function<std::vector<float>> {
-            {{ 18, propertyValue.asConstant() }},
-            1,
-        }};
+        MGLStyleValue<NSArray<NSNumber *> *> * functionStyleValue = [MGLStyleValue<NSArray<NSNumber *> *> valueWithInterpolationMode:MGLInterpolationModeInterval cameraStops:@{@18: constantStyleValue} options:nil];
+        layer.lineDashPattern = functionStyleValue;
+
+        mbgl::style::IntervalStops<std::vector<float>> intervalStops = { {{18, {1, 2}}} };
+        propertyValue = mbgl::style::CameraFunction<std::vector<float>> { intervalStops };
+        
         XCTAssertEqual(rawLayer->getLineDasharray(), propertyValue,
-                       @"Setting lineDashPattern to a function should update line-dasharray.");
-        XCTAssertEqualObjects(layer.lineDashPattern, styleValue,
-                              @"lineDashPattern should round-trip functions.");
+                       @"Setting lineDashPattern to a camera function should update line-dasharray.");
+        XCTAssertEqualObjects(layer.lineDashPattern, functionStyleValue,
+                              @"lineDashPattern should round-trip camera functions.");
+
+                              
 
         layer.lineDashPattern = nil;
         XCTAssertTrue(rawLayer->getLineDasharray().isUndefined(),
                       @"Unsetting lineDashPattern should return line-dasharray to the default value.");
         XCTAssertEqualObjects(layer.lineDashPattern, defaultStyleValue,
                               @"lineDashPattern should return the default value after being unset.");
+
+        functionStyleValue = [MGLStyleValue<NSArray<NSNumber *> *> valueWithInterpolationMode:MGLInterpolationModeIdentity sourceStops:nil attributeName:@"" options:nil];
+        XCTAssertThrowsSpecificNamed(layer.lineDashPattern = functionStyleValue, NSException, NSInvalidArgumentException, @"MGLStyleValue should raise an exception if it is applied to a property that cannot support it");
+
+        functionStyleValue = [MGLStyleValue<NSArray<NSNumber *> *> valueWithInterpolationMode:MGLInterpolationModeInterval compositeStops:@{@18: constantStyleValue} attributeName:@"" options:nil];
+        XCTAssertThrowsSpecificNamed(layer.lineDashPattern = functionStyleValue, NSException, NSInvalidArgumentException, @"MGLStyleValue should raise an exception if it is applied to a property that cannot support it");        
     }
 
     // line-gap-width
@@ -287,26 +351,49 @@
                       @"line-gap-width should be unset initially.");
         MGLStyleValue<NSNumber *> *defaultStyleValue = layer.lineGapWidth;
 
-        MGLStyleValue<NSNumber *> *styleValue = [MGLStyleValue<NSNumber *> valueWithRawValue:@0xff];
-        layer.lineGapWidth = styleValue;
-        mbgl::style::PropertyValue<float> propertyValue = { 0xff };
+        MGLStyleValue<NSNumber *> *constantStyleValue = [MGLStyleValue<NSNumber *> valueWithRawValue:@0xff];
+        layer.lineGapWidth = constantStyleValue;
+        mbgl::style::DataDrivenPropertyValue<float> propertyValue = { 0xff };
         XCTAssertEqual(rawLayer->getLineGapWidth(), propertyValue,
                        @"Setting lineGapWidth to a constant value should update line-gap-width.");
-        XCTAssertEqualObjects(layer.lineGapWidth, styleValue,
+        XCTAssertEqualObjects(layer.lineGapWidth, constantStyleValue,
                               @"lineGapWidth should round-trip constant values.");
 
-        styleValue = [MGLStyleValue<NSNumber *> valueWithStops:@{
-            @18: styleValue,
-        }];
-        layer.lineGapWidth = styleValue;
-        propertyValue = { mbgl::style::Function<float> {
-            {{ 18, propertyValue.asConstant() }},
-            1,
-        }};
+        MGLStyleValue<NSNumber *> * functionStyleValue = [MGLStyleValue<NSNumber *> valueWithInterpolationMode:MGLInterpolationModeInterval cameraStops:@{@18: constantStyleValue} options:nil];
+        layer.lineGapWidth = functionStyleValue;
+
+        mbgl::style::IntervalStops<float> intervalStops = { {{18, 0xff}} };
+        propertyValue = mbgl::style::CameraFunction<float> { intervalStops };
+        
         XCTAssertEqual(rawLayer->getLineGapWidth(), propertyValue,
-                       @"Setting lineGapWidth to a function should update line-gap-width.");
-        XCTAssertEqualObjects(layer.lineGapWidth, styleValue,
-                              @"lineGapWidth should round-trip functions.");
+                       @"Setting lineGapWidth to a camera function should update line-gap-width.");
+        XCTAssertEqualObjects(layer.lineGapWidth, functionStyleValue,
+                              @"lineGapWidth should round-trip camera functions.");
+
+        functionStyleValue = [MGLStyleValue<NSNumber *> valueWithInterpolationMode:MGLInterpolationModeExponential sourceStops:@{@18: constantStyleValue} attributeName:@"keyName" options:nil];
+        layer.lineGapWidth = functionStyleValue;
+
+        mbgl::style::ExponentialStops<float> exponentialStops = { {{18, 0xff}}, 1.0 };
+        propertyValue = mbgl::style::SourceFunction<float> { "keyName", exponentialStops };
+
+        XCTAssertEqual(rawLayer->getLineGapWidth(), propertyValue,
+                       @"Setting lineGapWidth to a source function should update line-gap-width.");
+        XCTAssertEqualObjects(layer.lineGapWidth, functionStyleValue,
+                              @"lineGapWidth should round-trip source functions.");
+
+        functionStyleValue = [MGLStyleValue<NSNumber *> valueWithInterpolationMode:MGLInterpolationModeExponential compositeStops:@{@10: @{@18: constantStyleValue}} attributeName:@"keyName" options:nil];
+        layer.lineGapWidth = functionStyleValue;
+
+        mbgl::style::ExponentialStops<float> innerStops = { { {18, 0xff}}, 1.0 };
+        std::map<float, mbgl::style::ExponentialStops<float>> compositeStops = { {10.0, innerStops} };
+
+        propertyValue = mbgl::style::CompositeFunction<float> { "keyName", compositeStops };
+
+        XCTAssertEqual(rawLayer->getLineGapWidth(), propertyValue,
+                       @"Setting lineGapWidth to a composite function should update line-gap-width.");
+        XCTAssertEqualObjects(layer.lineGapWidth, functionStyleValue,
+                              @"lineGapWidth should round-trip composite functions.");                                                                                                          
+                              
 
         layer.lineGapWidth = nil;
         XCTAssertTrue(rawLayer->getLineGapWidth().isUndefined(),
@@ -321,26 +408,49 @@
                       @"line-offset should be unset initially.");
         MGLStyleValue<NSNumber *> *defaultStyleValue = layer.lineOffset;
 
-        MGLStyleValue<NSNumber *> *styleValue = [MGLStyleValue<NSNumber *> valueWithRawValue:@0xff];
-        layer.lineOffset = styleValue;
-        mbgl::style::PropertyValue<float> propertyValue = { 0xff };
+        MGLStyleValue<NSNumber *> *constantStyleValue = [MGLStyleValue<NSNumber *> valueWithRawValue:@0xff];
+        layer.lineOffset = constantStyleValue;
+        mbgl::style::DataDrivenPropertyValue<float> propertyValue = { 0xff };
         XCTAssertEqual(rawLayer->getLineOffset(), propertyValue,
                        @"Setting lineOffset to a constant value should update line-offset.");
-        XCTAssertEqualObjects(layer.lineOffset, styleValue,
+        XCTAssertEqualObjects(layer.lineOffset, constantStyleValue,
                               @"lineOffset should round-trip constant values.");
 
-        styleValue = [MGLStyleValue<NSNumber *> valueWithStops:@{
-            @18: styleValue,
-        }];
-        layer.lineOffset = styleValue;
-        propertyValue = { mbgl::style::Function<float> {
-            {{ 18, propertyValue.asConstant() }},
-            1,
-        }};
+        MGLStyleValue<NSNumber *> * functionStyleValue = [MGLStyleValue<NSNumber *> valueWithInterpolationMode:MGLInterpolationModeInterval cameraStops:@{@18: constantStyleValue} options:nil];
+        layer.lineOffset = functionStyleValue;
+
+        mbgl::style::IntervalStops<float> intervalStops = { {{18, 0xff}} };
+        propertyValue = mbgl::style::CameraFunction<float> { intervalStops };
+        
         XCTAssertEqual(rawLayer->getLineOffset(), propertyValue,
-                       @"Setting lineOffset to a function should update line-offset.");
-        XCTAssertEqualObjects(layer.lineOffset, styleValue,
-                              @"lineOffset should round-trip functions.");
+                       @"Setting lineOffset to a camera function should update line-offset.");
+        XCTAssertEqualObjects(layer.lineOffset, functionStyleValue,
+                              @"lineOffset should round-trip camera functions.");
+
+        functionStyleValue = [MGLStyleValue<NSNumber *> valueWithInterpolationMode:MGLInterpolationModeExponential sourceStops:@{@18: constantStyleValue} attributeName:@"keyName" options:nil];
+        layer.lineOffset = functionStyleValue;
+
+        mbgl::style::ExponentialStops<float> exponentialStops = { {{18, 0xff}}, 1.0 };
+        propertyValue = mbgl::style::SourceFunction<float> { "keyName", exponentialStops };
+
+        XCTAssertEqual(rawLayer->getLineOffset(), propertyValue,
+                       @"Setting lineOffset to a source function should update line-offset.");
+        XCTAssertEqualObjects(layer.lineOffset, functionStyleValue,
+                              @"lineOffset should round-trip source functions.");
+
+        functionStyleValue = [MGLStyleValue<NSNumber *> valueWithInterpolationMode:MGLInterpolationModeExponential compositeStops:@{@10: @{@18: constantStyleValue}} attributeName:@"keyName" options:nil];
+        layer.lineOffset = functionStyleValue;
+
+        mbgl::style::ExponentialStops<float> innerStops = { { {18, 0xff}}, 1.0 };
+        std::map<float, mbgl::style::ExponentialStops<float>> compositeStops = { {10.0, innerStops} };
+
+        propertyValue = mbgl::style::CompositeFunction<float> { "keyName", compositeStops };
+
+        XCTAssertEqual(rawLayer->getLineOffset(), propertyValue,
+                       @"Setting lineOffset to a composite function should update line-offset.");
+        XCTAssertEqualObjects(layer.lineOffset, functionStyleValue,
+                              @"lineOffset should round-trip composite functions.");                                                                                                          
+                              
 
         layer.lineOffset = nil;
         XCTAssertTrue(rawLayer->getLineOffset().isUndefined(),
@@ -355,26 +465,49 @@
                       @"line-opacity should be unset initially.");
         MGLStyleValue<NSNumber *> *defaultStyleValue = layer.lineOpacity;
 
-        MGLStyleValue<NSNumber *> *styleValue = [MGLStyleValue<NSNumber *> valueWithRawValue:@0xff];
-        layer.lineOpacity = styleValue;
-        mbgl::style::PropertyValue<float> propertyValue = { 0xff };
+        MGLStyleValue<NSNumber *> *constantStyleValue = [MGLStyleValue<NSNumber *> valueWithRawValue:@0xff];
+        layer.lineOpacity = constantStyleValue;
+        mbgl::style::DataDrivenPropertyValue<float> propertyValue = { 0xff };
         XCTAssertEqual(rawLayer->getLineOpacity(), propertyValue,
                        @"Setting lineOpacity to a constant value should update line-opacity.");
-        XCTAssertEqualObjects(layer.lineOpacity, styleValue,
+        XCTAssertEqualObjects(layer.lineOpacity, constantStyleValue,
                               @"lineOpacity should round-trip constant values.");
 
-        styleValue = [MGLStyleValue<NSNumber *> valueWithStops:@{
-            @18: styleValue,
-        }];
-        layer.lineOpacity = styleValue;
-        propertyValue = { mbgl::style::Function<float> {
-            {{ 18, propertyValue.asConstant() }},
-            1,
-        }};
+        MGLStyleValue<NSNumber *> * functionStyleValue = [MGLStyleValue<NSNumber *> valueWithInterpolationMode:MGLInterpolationModeInterval cameraStops:@{@18: constantStyleValue} options:nil];
+        layer.lineOpacity = functionStyleValue;
+
+        mbgl::style::IntervalStops<float> intervalStops = { {{18, 0xff}} };
+        propertyValue = mbgl::style::CameraFunction<float> { intervalStops };
+        
         XCTAssertEqual(rawLayer->getLineOpacity(), propertyValue,
-                       @"Setting lineOpacity to a function should update line-opacity.");
-        XCTAssertEqualObjects(layer.lineOpacity, styleValue,
-                              @"lineOpacity should round-trip functions.");
+                       @"Setting lineOpacity to a camera function should update line-opacity.");
+        XCTAssertEqualObjects(layer.lineOpacity, functionStyleValue,
+                              @"lineOpacity should round-trip camera functions.");
+
+        functionStyleValue = [MGLStyleValue<NSNumber *> valueWithInterpolationMode:MGLInterpolationModeExponential sourceStops:@{@18: constantStyleValue} attributeName:@"keyName" options:nil];
+        layer.lineOpacity = functionStyleValue;
+
+        mbgl::style::ExponentialStops<float> exponentialStops = { {{18, 0xff}}, 1.0 };
+        propertyValue = mbgl::style::SourceFunction<float> { "keyName", exponentialStops };
+
+        XCTAssertEqual(rawLayer->getLineOpacity(), propertyValue,
+                       @"Setting lineOpacity to a source function should update line-opacity.");
+        XCTAssertEqualObjects(layer.lineOpacity, functionStyleValue,
+                              @"lineOpacity should round-trip source functions.");
+
+        functionStyleValue = [MGLStyleValue<NSNumber *> valueWithInterpolationMode:MGLInterpolationModeExponential compositeStops:@{@10: @{@18: constantStyleValue}} attributeName:@"keyName" options:nil];
+        layer.lineOpacity = functionStyleValue;
+
+        mbgl::style::ExponentialStops<float> innerStops = { { {18, 0xff}}, 1.0 };
+        std::map<float, mbgl::style::ExponentialStops<float>> compositeStops = { {10.0, innerStops} };
+
+        propertyValue = mbgl::style::CompositeFunction<float> { "keyName", compositeStops };
+
+        XCTAssertEqual(rawLayer->getLineOpacity(), propertyValue,
+                       @"Setting lineOpacity to a composite function should update line-opacity.");
+        XCTAssertEqualObjects(layer.lineOpacity, functionStyleValue,
+                              @"lineOpacity should round-trip composite functions.");                                                                                                          
+                              
 
         layer.lineOpacity = nil;
         XCTAssertTrue(rawLayer->getLineOpacity().isUndefined(),
@@ -389,32 +522,38 @@
                       @"line-pattern should be unset initially.");
         MGLStyleValue<NSString *> *defaultStyleValue = layer.linePattern;
 
-        MGLStyleValue<NSString *> *styleValue = [MGLStyleValue<NSString *> valueWithRawValue:@"Line Pattern"];
-        layer.linePattern = styleValue;
+        MGLStyleValue<NSString *> *constantStyleValue = [MGLStyleValue<NSString *> valueWithRawValue:@"Line Pattern"];
+        layer.linePattern = constantStyleValue;
         mbgl::style::PropertyValue<std::string> propertyValue = { "Line Pattern" };
         XCTAssertEqual(rawLayer->getLinePattern(), propertyValue,
                        @"Setting linePattern to a constant value should update line-pattern.");
-        XCTAssertEqualObjects(layer.linePattern, styleValue,
+        XCTAssertEqualObjects(layer.linePattern, constantStyleValue,
                               @"linePattern should round-trip constant values.");
 
-        styleValue = [MGLStyleValue<NSString *> valueWithStops:@{
-            @18: styleValue,
-        }];
-        layer.linePattern = styleValue;
-        propertyValue = { mbgl::style::Function<std::string> {
-            {{ 18, propertyValue.asConstant() }},
-            1,
-        }};
+        MGLStyleValue<NSString *> * functionStyleValue = [MGLStyleValue<NSString *> valueWithInterpolationMode:MGLInterpolationModeInterval cameraStops:@{@18: constantStyleValue} options:nil];
+        layer.linePattern = functionStyleValue;
+
+        mbgl::style::IntervalStops<std::string> intervalStops = { {{18, "Line Pattern"}} };
+        propertyValue = mbgl::style::CameraFunction<std::string> { intervalStops };
+        
         XCTAssertEqual(rawLayer->getLinePattern(), propertyValue,
-                       @"Setting linePattern to a function should update line-pattern.");
-        XCTAssertEqualObjects(layer.linePattern, styleValue,
-                              @"linePattern should round-trip functions.");
+                       @"Setting linePattern to a camera function should update line-pattern.");
+        XCTAssertEqualObjects(layer.linePattern, functionStyleValue,
+                              @"linePattern should round-trip camera functions.");
+
+                              
 
         layer.linePattern = nil;
         XCTAssertTrue(rawLayer->getLinePattern().isUndefined(),
                       @"Unsetting linePattern should return line-pattern to the default value.");
         XCTAssertEqualObjects(layer.linePattern, defaultStyleValue,
                               @"linePattern should return the default value after being unset.");
+
+        functionStyleValue = [MGLStyleValue<NSString *> valueWithInterpolationMode:MGLInterpolationModeIdentity sourceStops:nil attributeName:@"" options:nil];
+        XCTAssertThrowsSpecificNamed(layer.linePattern = functionStyleValue, NSException, NSInvalidArgumentException, @"MGLStyleValue should raise an exception if it is applied to a property that cannot support it");
+
+        functionStyleValue = [MGLStyleValue<NSString *> valueWithInterpolationMode:MGLInterpolationModeInterval compositeStops:@{@18: constantStyleValue} attributeName:@"" options:nil];
+        XCTAssertThrowsSpecificNamed(layer.linePattern = functionStyleValue, NSException, NSInvalidArgumentException, @"MGLStyleValue should raise an exception if it is applied to a property that cannot support it");        
     }
 
     // line-translate
@@ -423,32 +562,32 @@
                       @"line-translate should be unset initially.");
         MGLStyleValue<NSValue *> *defaultStyleValue = layer.lineTranslation;
 
-        MGLStyleValue<NSValue *> *styleValue = [MGLStyleValue<NSValue *> valueWithRawValue:
+        MGLStyleValue<NSValue *> *constantStyleValue = [MGLStyleValue<NSValue *> valueWithRawValue:
 #if TARGET_OS_IPHONE
             [NSValue valueWithCGVector:CGVectorMake(1, 1)]
 #else
             [NSValue valueWithMGLVector:CGVectorMake(1, -1)]
 #endif
         ];
-        layer.lineTranslation = styleValue;
+        layer.lineTranslation = constantStyleValue;
         mbgl::style::PropertyValue<std::array<float, 2>> propertyValue = { { 1, 1 } };
         XCTAssertEqual(rawLayer->getLineTranslate(), propertyValue,
                        @"Setting lineTranslation to a constant value should update line-translate.");
-        XCTAssertEqualObjects(layer.lineTranslation, styleValue,
+        XCTAssertEqualObjects(layer.lineTranslation, constantStyleValue,
                               @"lineTranslation should round-trip constant values.");
 
-        styleValue = [MGLStyleValue<NSValue *> valueWithStops:@{
-            @18: styleValue,
-        }];
-        layer.lineTranslation = styleValue;
-        propertyValue = { mbgl::style::Function<std::array<float, 2>> {
-            {{ 18, propertyValue.asConstant() }},
-            1,
-        }};
+        MGLStyleValue<NSValue *> * functionStyleValue = [MGLStyleValue<NSValue *> valueWithInterpolationMode:MGLInterpolationModeInterval cameraStops:@{@18: constantStyleValue} options:nil];
+        layer.lineTranslation = functionStyleValue;
+
+        mbgl::style::IntervalStops<std::array<float, 2>> intervalStops = { {{18, { 1, 1 }}} };
+        propertyValue = mbgl::style::CameraFunction<std::array<float, 2>> { intervalStops };
+        
         XCTAssertEqual(rawLayer->getLineTranslate(), propertyValue,
-                       @"Setting lineTranslation to a function should update line-translate.");
-        XCTAssertEqualObjects(layer.lineTranslation, styleValue,
-                              @"lineTranslation should round-trip functions.");
+                       @"Setting lineTranslation to a camera function should update line-translate.");
+        XCTAssertEqualObjects(layer.lineTranslation, functionStyleValue,
+                              @"lineTranslation should round-trip camera functions.");
+
+                              
 
         layer.lineTranslation = nil;
         XCTAssertTrue(rawLayer->getLineTranslate().isUndefined(),
@@ -463,32 +602,38 @@
                       @"line-translate-anchor should be unset initially.");
         MGLStyleValue<NSValue *> *defaultStyleValue = layer.lineTranslationAnchor;
 
-        MGLStyleValue<NSValue *> *styleValue = [MGLStyleValue<NSValue *> valueWithRawValue:[NSValue valueWithMGLLineTranslationAnchor:MGLLineTranslationAnchorViewport]];
-        layer.lineTranslationAnchor = styleValue;
+        MGLStyleValue<NSValue *> *constantStyleValue = [MGLStyleValue<NSValue *> valueWithRawValue:[NSValue valueWithMGLLineTranslationAnchor:MGLLineTranslationAnchorViewport]];
+        layer.lineTranslationAnchor = constantStyleValue;
         mbgl::style::PropertyValue<mbgl::style::TranslateAnchorType> propertyValue = { mbgl::style::TranslateAnchorType::Viewport };
         XCTAssertEqual(rawLayer->getLineTranslateAnchor(), propertyValue,
                        @"Setting lineTranslationAnchor to a constant value should update line-translate-anchor.");
-        XCTAssertEqualObjects(layer.lineTranslationAnchor, styleValue,
+        XCTAssertEqualObjects(layer.lineTranslationAnchor, constantStyleValue,
                               @"lineTranslationAnchor should round-trip constant values.");
 
-        styleValue = [MGLStyleValue<NSValue *> valueWithStops:@{
-            @18: styleValue,
-        }];
-        layer.lineTranslationAnchor = styleValue;
-        propertyValue = { mbgl::style::Function<mbgl::style::TranslateAnchorType> {
-            {{ 18, propertyValue.asConstant() }},
-            1,
-        }};
+        MGLStyleValue<NSValue *> * functionStyleValue = [MGLStyleValue<NSValue *> valueWithInterpolationMode:MGLInterpolationModeInterval cameraStops:@{@18: constantStyleValue} options:nil];
+        layer.lineTranslationAnchor = functionStyleValue;
+
+        mbgl::style::IntervalStops<mbgl::style::TranslateAnchorType> intervalStops = { {{18, mbgl::style::TranslateAnchorType::Viewport}} };
+        propertyValue = mbgl::style::CameraFunction<mbgl::style::TranslateAnchorType> { intervalStops };
+        
         XCTAssertEqual(rawLayer->getLineTranslateAnchor(), propertyValue,
-                       @"Setting lineTranslationAnchor to a function should update line-translate-anchor.");
-        XCTAssertEqualObjects(layer.lineTranslationAnchor, styleValue,
-                              @"lineTranslationAnchor should round-trip functions.");
+                       @"Setting lineTranslationAnchor to a camera function should update line-translate-anchor.");
+        XCTAssertEqualObjects(layer.lineTranslationAnchor, functionStyleValue,
+                              @"lineTranslationAnchor should round-trip camera functions.");
+
+                              
 
         layer.lineTranslationAnchor = nil;
         XCTAssertTrue(rawLayer->getLineTranslateAnchor().isUndefined(),
                       @"Unsetting lineTranslationAnchor should return line-translate-anchor to the default value.");
         XCTAssertEqualObjects(layer.lineTranslationAnchor, defaultStyleValue,
                               @"lineTranslationAnchor should return the default value after being unset.");
+
+        functionStyleValue = [MGLStyleValue<NSValue *> valueWithInterpolationMode:MGLInterpolationModeIdentity sourceStops:nil attributeName:@"" options:nil];
+        XCTAssertThrowsSpecificNamed(layer.lineTranslationAnchor = functionStyleValue, NSException, NSInvalidArgumentException, @"MGLStyleValue should raise an exception if it is applied to a property that cannot support it");
+
+        functionStyleValue = [MGLStyleValue<NSValue *> valueWithInterpolationMode:MGLInterpolationModeInterval compositeStops:@{@18: constantStyleValue} attributeName:@"" options:nil];
+        XCTAssertThrowsSpecificNamed(layer.lineTranslationAnchor = functionStyleValue, NSException, NSInvalidArgumentException, @"MGLStyleValue should raise an exception if it is applied to a property that cannot support it");        
     }
 
     // line-width
@@ -497,26 +642,26 @@
                       @"line-width should be unset initially.");
         MGLStyleValue<NSNumber *> *defaultStyleValue = layer.lineWidth;
 
-        MGLStyleValue<NSNumber *> *styleValue = [MGLStyleValue<NSNumber *> valueWithRawValue:@0xff];
-        layer.lineWidth = styleValue;
+        MGLStyleValue<NSNumber *> *constantStyleValue = [MGLStyleValue<NSNumber *> valueWithRawValue:@0xff];
+        layer.lineWidth = constantStyleValue;
         mbgl::style::PropertyValue<float> propertyValue = { 0xff };
         XCTAssertEqual(rawLayer->getLineWidth(), propertyValue,
                        @"Setting lineWidth to a constant value should update line-width.");
-        XCTAssertEqualObjects(layer.lineWidth, styleValue,
+        XCTAssertEqualObjects(layer.lineWidth, constantStyleValue,
                               @"lineWidth should round-trip constant values.");
 
-        styleValue = [MGLStyleValue<NSNumber *> valueWithStops:@{
-            @18: styleValue,
-        }];
-        layer.lineWidth = styleValue;
-        propertyValue = { mbgl::style::Function<float> {
-            {{ 18, propertyValue.asConstant() }},
-            1,
-        }};
+        MGLStyleValue<NSNumber *> * functionStyleValue = [MGLStyleValue<NSNumber *> valueWithInterpolationMode:MGLInterpolationModeInterval cameraStops:@{@18: constantStyleValue} options:nil];
+        layer.lineWidth = functionStyleValue;
+
+        mbgl::style::IntervalStops<float> intervalStops = { {{18, 0xff}} };
+        propertyValue = mbgl::style::CameraFunction<float> { intervalStops };
+        
         XCTAssertEqual(rawLayer->getLineWidth(), propertyValue,
-                       @"Setting lineWidth to a function should update line-width.");
-        XCTAssertEqualObjects(layer.lineWidth, styleValue,
-                              @"lineWidth should round-trip functions.");
+                       @"Setting lineWidth to a camera function should update line-width.");
+        XCTAssertEqualObjects(layer.lineWidth, functionStyleValue,
+                              @"lineWidth should round-trip camera functions.");
+
+                              
 
         layer.lineWidth = nil;
         XCTAssertTrue(rawLayer->getLineWidth().isUndefined(),

platform/darwin/test/MGLRasterStyleLayerTests.mm

@@ -1,5 +1,5 @@
 // This file is generated.
-// Edit platform/darwin/scripts/generate-style-code.js, then run `make style-code-darwin`.
+// Edit platform/darwin/scripts/generate-style-code.js, then run `make darwin-style-code`.
 
 #import "MGLStyleLayerTests.h"
 
@@ -31,26 +31,26 @@
                       @"raster-brightness-max should be unset initially.");
         MGLStyleValue<NSNumber *> *defaultStyleValue = layer.maximumRasterBrightness;
 
-        MGLStyleValue<NSNumber *> *styleValue = [MGLStyleValue<NSNumber *> valueWithRawValue:@0xff];
-        layer.maximumRasterBrightness = styleValue;
+        MGLStyleValue<NSNumber *> *constantStyleValue = [MGLStyleValue<NSNumber *> valueWithRawValue:@0xff];
+        layer.maximumRasterBrightness = constantStyleValue;
         mbgl::style::PropertyValue<float> propertyValue = { 0xff };
         XCTAssertEqual(rawLayer->getRasterBrightnessMax(), propertyValue,
                        @"Setting maximumRasterBrightness to a constant value should update raster-brightness-max.");
-        XCTAssertEqualObjects(layer.maximumRasterBrightness, styleValue,
+        XCTAssertEqualObjects(layer.maximumRasterBrightness, constantStyleValue,
                               @"maximumRasterBrightness should round-trip constant values.");
 
-        styleValue = [MGLStyleValue<NSNumber *> valueWithStops:@{
-            @18: styleValue,
-        }];
-        layer.maximumRasterBrightness = styleValue;
-        propertyValue = { mbgl::style::Function<float> {
-            {{ 18, propertyValue.asConstant() }},
-            1,
-        }};
+        MGLStyleValue<NSNumber *> * functionStyleValue = [MGLStyleValue<NSNumber *> valueWithInterpolationMode:MGLInterpolationModeInterval cameraStops:@{@18: constantStyleValue} options:nil];
+        layer.maximumRasterBrightness = functionStyleValue;
+
+        mbgl::style::IntervalStops<float> intervalStops = { {{18, 0xff}} };
+        propertyValue = mbgl::style::CameraFunction<float> { intervalStops };
+        
         XCTAssertEqual(rawLayer->getRasterBrightnessMax(), propertyValue,
-                       @"Setting maximumRasterBrightness to a function should update raster-brightness-max.");
-        XCTAssertEqualObjects(layer.maximumRasterBrightness, styleValue,
-                              @"maximumRasterBrightness should round-trip functions.");
+                       @"Setting maximumRasterBrightness to a camera function should update raster-brightness-max.");
+        XCTAssertEqualObjects(layer.maximumRasterBrightness, functionStyleValue,
+                              @"maximumRasterBrightness should round-trip camera functions.");
+
+                              
 
         layer.maximumRasterBrightness = nil;
         XCTAssertTrue(rawLayer->getRasterBrightnessMax().isUndefined(),
@@ -65,26 +65,26 @@
                       @"raster-brightness-min should be unset initially.");
         MGLStyleValue<NSNumber *> *defaultStyleValue = layer.minimumRasterBrightness;
 
-        MGLStyleValue<NSNumber *> *styleValue = [MGLStyleValue<NSNumber *> valueWithRawValue:@0xff];
-        layer.minimumRasterBrightness = styleValue;
+        MGLStyleValue<NSNumber *> *constantStyleValue = [MGLStyleValue<NSNumber *> valueWithRawValue:@0xff];
+        layer.minimumRasterBrightness = constantStyleValue;
         mbgl::style::PropertyValue<float> propertyValue = { 0xff };
         XCTAssertEqual(rawLayer->getRasterBrightnessMin(), propertyValue,
                        @"Setting minimumRasterBrightness to a constant value should update raster-brightness-min.");
-        XCTAssertEqualObjects(layer.minimumRasterBrightness, styleValue,
+        XCTAssertEqualObjects(layer.minimumRasterBrightness, constantStyleValue,
                               @"minimumRasterBrightness should round-trip constant values.");
 
-        styleValue = [MGLStyleValue<NSNumber *> valueWithStops:@{
-            @18: styleValue,
-        }];
-        layer.minimumRasterBrightness = styleValue;
-        propertyValue = { mbgl::style::Function<float> {
-            {{ 18, propertyValue.asConstant() }},
-            1,
-        }};
+        MGLStyleValue<NSNumber *> * functionStyleValue = [MGLStyleValue<NSNumber *> valueWithInterpolationMode:MGLInterpolationModeInterval cameraStops:@{@18: constantStyleValue} options:nil];
+        layer.minimumRasterBrightness = functionStyleValue;
+
+        mbgl::style::IntervalStops<float> intervalStops = { {{18, 0xff}} };
+        propertyValue = mbgl::style::CameraFunction<float> { intervalStops };
+        
         XCTAssertEqual(rawLayer->getRasterBrightnessMin(), propertyValue,
-                       @"Setting minimumRasterBrightness to a function should update raster-brightness-min.");
-        XCTAssertEqualObjects(layer.minimumRasterBrightness, styleValue,
-                              @"minimumRasterBrightness should round-trip functions.");
+                       @"Setting minimumRasterBrightness to a camera function should update raster-brightness-min.");
+        XCTAssertEqualObjects(layer.minimumRasterBrightness, functionStyleValue,
+                              @"minimumRasterBrightness should round-trip camera functions.");
+
+                              
 
         layer.minimumRasterBrightness = nil;
         XCTAssertTrue(rawLayer->getRasterBrightnessMin().isUndefined(),
@@ -99,26 +99,26 @@
                       @"raster-contrast should be unset initially.");
         MGLStyleValue<NSNumber *> *defaultStyleValue = layer.rasterContrast;
 
-        MGLStyleValue<NSNumber *> *styleValue = [MGLStyleValue<NSNumber *> valueWithRawValue:@0xff];
-        layer.rasterContrast = styleValue;
+        MGLStyleValue<NSNumber *> *constantStyleValue = [MGLStyleValue<NSNumber *> valueWithRawValue:@0xff];
+        layer.rasterContrast = constantStyleValue;
         mbgl::style::PropertyValue<float> propertyValue = { 0xff };
         XCTAssertEqual(rawLayer->getRasterContrast(), propertyValue,
                        @"Setting rasterContrast to a constant value should update raster-contrast.");
-        XCTAssertEqualObjects(layer.rasterContrast, styleValue,
+        XCTAssertEqualObjects(layer.rasterContrast, constantStyleValue,
                               @"rasterContrast should round-trip constant values.");
 
-        styleValue = [MGLStyleValue<NSNumber *> valueWithStops:@{
-            @18: styleValue,
-        }];
-        layer.rasterContrast = styleValue;
-        propertyValue = { mbgl::style::Function<float> {
-            {{ 18, propertyValue.asConstant() }},
-            1,
-        }};
+        MGLStyleValue<NSNumber *> * functionStyleValue = [MGLStyleValue<NSNumber *> valueWithInterpolationMode:MGLInterpolationModeInterval cameraStops:@{@18: constantStyleValue} options:nil];
+        layer.rasterContrast = functionStyleValue;
+
+        mbgl::style::IntervalStops<float> intervalStops = { {{18, 0xff}} };
+        propertyValue = mbgl::style::CameraFunction<float> { intervalStops };
+        
         XCTAssertEqual(rawLayer->getRasterContrast(), propertyValue,
-                       @"Setting rasterContrast to a function should update raster-contrast.");
-        XCTAssertEqualObjects(layer.rasterContrast, styleValue,
-                              @"rasterContrast should round-trip functions.");
+                       @"Setting rasterContrast to a camera function should update raster-contrast.");
+        XCTAssertEqualObjects(layer.rasterContrast, functionStyleValue,
+                              @"rasterContrast should round-trip camera functions.");
+
+                              
 
         layer.rasterContrast = nil;
         XCTAssertTrue(rawLayer->getRasterContrast().isUndefined(),
@@ -133,26 +133,26 @@
                       @"raster-fade-duration should be unset initially.");
         MGLStyleValue<NSNumber *> *defaultStyleValue = layer.rasterFadeDuration;
 
-        MGLStyleValue<NSNumber *> *styleValue = [MGLStyleValue<NSNumber *> valueWithRawValue:@0xff];
-        layer.rasterFadeDuration = styleValue;
+        MGLStyleValue<NSNumber *> *constantStyleValue = [MGLStyleValue<NSNumber *> valueWithRawValue:@0xff];
+        layer.rasterFadeDuration = constantStyleValue;
         mbgl::style::PropertyValue<float> propertyValue = { 0xff };
         XCTAssertEqual(rawLayer->getRasterFadeDuration(), propertyValue,
                        @"Setting rasterFadeDuration to a constant value should update raster-fade-duration.");
-        XCTAssertEqualObjects(layer.rasterFadeDuration, styleValue,
+        XCTAssertEqualObjects(layer.rasterFadeDuration, constantStyleValue,
                               @"rasterFadeDuration should round-trip constant values.");
 
-        styleValue = [MGLStyleValue<NSNumber *> valueWithStops:@{
-            @18: styleValue,
-        }];
-        layer.rasterFadeDuration = styleValue;
-        propertyValue = { mbgl::style::Function<float> {
-            {{ 18, propertyValue.asConstant() }},
-            1,
-        }};
+        MGLStyleValue<NSNumber *> * functionStyleValue = [MGLStyleValue<NSNumber *> valueWithInterpolationMode:MGLInterpolationModeInterval cameraStops:@{@18: constantStyleValue} options:nil];
+        layer.rasterFadeDuration = functionStyleValue;
+
+        mbgl::style::IntervalStops<float> intervalStops = { {{18, 0xff}} };
+        propertyValue = mbgl::style::CameraFunction<float> { intervalStops };
+        
         XCTAssertEqual(rawLayer->getRasterFadeDuration(), propertyValue,
-                       @"Setting rasterFadeDuration to a function should update raster-fade-duration.");
-        XCTAssertEqualObjects(layer.rasterFadeDuration, styleValue,
-                              @"rasterFadeDuration should round-trip functions.");
+                       @"Setting rasterFadeDuration to a camera function should update raster-fade-duration.");
+        XCTAssertEqualObjects(layer.rasterFadeDuration, functionStyleValue,
+                              @"rasterFadeDuration should round-trip camera functions.");
+
+                              
 
         layer.rasterFadeDuration = nil;
         XCTAssertTrue(rawLayer->getRasterFadeDuration().isUndefined(),
@@ -167,26 +167,26 @@
                       @"raster-hue-rotate should be unset initially.");
         MGLStyleValue<NSNumber *> *defaultStyleValue = layer.rasterHueRotation;
 
-        MGLStyleValue<NSNumber *> *styleValue = [MGLStyleValue<NSNumber *> valueWithRawValue:@0xff];
-        layer.rasterHueRotation = styleValue;
+        MGLStyleValue<NSNumber *> *constantStyleValue = [MGLStyleValue<NSNumber *> valueWithRawValue:@0xff];
+        layer.rasterHueRotation = constantStyleValue;
         mbgl::style::PropertyValue<float> propertyValue = { 0xff };
         XCTAssertEqual(rawLayer->getRasterHueRotate(), propertyValue,
                        @"Setting rasterHueRotation to a constant value should update raster-hue-rotate.");
-        XCTAssertEqualObjects(layer.rasterHueRotation, styleValue,
+        XCTAssertEqualObjects(layer.rasterHueRotation, constantStyleValue,
                               @"rasterHueRotation should round-trip constant values.");
 
-        styleValue = [MGLStyleValue<NSNumber *> valueWithStops:@{
-            @18: styleValue,
-        }];
-        layer.rasterHueRotation = styleValue;
-        propertyValue = { mbgl::style::Function<float> {
-            {{ 18, propertyValue.asConstant() }},
-            1,
-        }};
+        MGLStyleValue<NSNumber *> * functionStyleValue = [MGLStyleValue<NSNumber *> valueWithInterpolationMode:MGLInterpolationModeInterval cameraStops:@{@18: constantStyleValue} options:nil];
+        layer.rasterHueRotation = functionStyleValue;
+
+        mbgl::style::IntervalStops<float> intervalStops = { {{18, 0xff}} };
+        propertyValue = mbgl::style::CameraFunction<float> { intervalStops };
+        
         XCTAssertEqual(rawLayer->getRasterHueRotate(), propertyValue,
-                       @"Setting rasterHueRotation to a function should update raster-hue-rotate.");
-        XCTAssertEqualObjects(layer.rasterHueRotation, styleValue,
-                              @"rasterHueRotation should round-trip functions.");
+                       @"Setting rasterHueRotation to a camera function should update raster-hue-rotate.");
+        XCTAssertEqualObjects(layer.rasterHueRotation, functionStyleValue,
+                              @"rasterHueRotation should round-trip camera functions.");
+
+                              
 
         layer.rasterHueRotation = nil;
         XCTAssertTrue(rawLayer->getRasterHueRotate().isUndefined(),
@@ -201,26 +201,26 @@
                       @"raster-opacity should be unset initially.");
         MGLStyleValue<NSNumber *> *defaultStyleValue = layer.rasterOpacity;
 
-        MGLStyleValue<NSNumber *> *styleValue = [MGLStyleValue<NSNumber *> valueWithRawValue:@0xff];
-        layer.rasterOpacity = styleValue;
+        MGLStyleValue<NSNumber *> *constantStyleValue = [MGLStyleValue<NSNumber *> valueWithRawValue:@0xff];
+        layer.rasterOpacity = constantStyleValue;
         mbgl::style::PropertyValue<float> propertyValue = { 0xff };
         XCTAssertEqual(rawLayer->getRasterOpacity(), propertyValue,
                        @"Setting rasterOpacity to a constant value should update raster-opacity.");
-        XCTAssertEqualObjects(layer.rasterOpacity, styleValue,
+        XCTAssertEqualObjects(layer.rasterOpacity, constantStyleValue,
                               @"rasterOpacity should round-trip constant values.");
 
-        styleValue = [MGLStyleValue<NSNumber *> valueWithStops:@{
-            @18: styleValue,
-        }];
-        layer.rasterOpacity = styleValue;
-        propertyValue = { mbgl::style::Function<float> {
-            {{ 18, propertyValue.asConstant() }},
-            1,
-        }};
+        MGLStyleValue<NSNumber *> * functionStyleValue = [MGLStyleValue<NSNumber *> valueWithInterpolationMode:MGLInterpolationModeInterval cameraStops:@{@18: constantStyleValue} options:nil];
+        layer.rasterOpacity = functionStyleValue;
+
+        mbgl::style::IntervalStops<float> intervalStops = { {{18, 0xff}} };
+        propertyValue = mbgl::style::CameraFunction<float> { intervalStops };
+        
         XCTAssertEqual(rawLayer->getRasterOpacity(), propertyValue,
-                       @"Setting rasterOpacity to a function should update raster-opacity.");
-        XCTAssertEqualObjects(layer.rasterOpacity, styleValue,
-                              @"rasterOpacity should round-trip functions.");
+                       @"Setting rasterOpacity to a camera function should update raster-opacity.");
+        XCTAssertEqualObjects(layer.rasterOpacity, functionStyleValue,
+                              @"rasterOpacity should round-trip camera functions.");
+
+                              
 
         layer.rasterOpacity = nil;
         XCTAssertTrue(rawLayer->getRasterOpacity().isUndefined(),
@@ -235,26 +235,26 @@
                       @"raster-saturation should be unset initially.");
         MGLStyleValue<NSNumber *> *defaultStyleValue = layer.rasterSaturation;
 
-        MGLStyleValue<NSNumber *> *styleValue = [MGLStyleValue<NSNumber *> valueWithRawValue:@0xff];
-        layer.rasterSaturation = styleValue;
+        MGLStyleValue<NSNumber *> *constantStyleValue = [MGLStyleValue<NSNumber *> valueWithRawValue:@0xff];
+        layer.rasterSaturation = constantStyleValue;
         mbgl::style::PropertyValue<float> propertyValue = { 0xff };
         XCTAssertEqual(rawLayer->getRasterSaturation(), propertyValue,
                        @"Setting rasterSaturation to a constant value should update raster-saturation.");
-        XCTAssertEqualObjects(layer.rasterSaturation, styleValue,
+        XCTAssertEqualObjects(layer.rasterSaturation, constantStyleValue,
                               @"rasterSaturation should round-trip constant values.");
 
-        styleValue = [MGLStyleValue<NSNumber *> valueWithStops:@{
-            @18: styleValue,
-        }];
-        layer.rasterSaturation = styleValue;
-        propertyValue = { mbgl::style::Function<float> {
-            {{ 18, propertyValue.asConstant() }},
-            1,
-        }};
+        MGLStyleValue<NSNumber *> * functionStyleValue = [MGLStyleValue<NSNumber *> valueWithInterpolationMode:MGLInterpolationModeInterval cameraStops:@{@18: constantStyleValue} options:nil];
+        layer.rasterSaturation = functionStyleValue;
+
+        mbgl::style::IntervalStops<float> intervalStops = { {{18, 0xff}} };
+        propertyValue = mbgl::style::CameraFunction<float> { intervalStops };
+        
         XCTAssertEqual(rawLayer->getRasterSaturation(), propertyValue,
-                       @"Setting rasterSaturation to a function should update raster-saturation.");
-        XCTAssertEqualObjects(layer.rasterSaturation, styleValue,
-                              @"rasterSaturation should round-trip functions.");
+                       @"Setting rasterSaturation to a camera function should update raster-saturation.");
+        XCTAssertEqualObjects(layer.rasterSaturation, functionStyleValue,
+                              @"rasterSaturation should round-trip camera functions.");
+
+                              
 
         layer.rasterSaturation = nil;
         XCTAssertTrue(rawLayer->getRasterSaturation().isUndefined(),

platform/darwin/test/MGLStyleLayerTests.mm.ejs

@@ -4,7 +4,7 @@
   const enumProperties = locals.enumProperties;
 -%>
 // This file is generated.
-// Edit platform/darwin/scripts/generate-style-code.js, then run `make style-code-darwin`.
+// Edit platform/darwin/scripts/generate-style-code.js, then run `make darwin-style-code`.
 
 #import "MGLStyleLayerTests.h"
 
@@ -61,26 +61,54 @@
                       @"<%- originalPropertyName(property) %> should be unset initially.");
         MGLStyleValue<<%- propertyType(property) %>> *defaultStyleValue = layer.<%- objCName(property) %>;
 
-        MGLStyleValue<<%- propertyType(property) %>> *styleValue = [MGLStyleValue<<%- propertyType(property) %>> valueWithRawValue:<%- objCTestValue(property, type, 3) %>];
-        layer.<%- objCName(property) %> = styleValue;
+        MGLStyleValue<<%- propertyType(property) %>> *constantStyleValue = [MGLStyleValue<<%- propertyType(property) %>> valueWithRawValue:<%- objCTestValue(property, type, 3) %>];
+        layer.<%- objCName(property) %> = constantStyleValue;
+<% if (property["property-function"]) { -%>
+        mbgl::style::DataDrivenPropertyValue<<%- mbglType(property) %>> propertyValue = { <%- mbglTestValue(property, type) %> };
+<% } else { -%>
         mbgl::style::PropertyValue<<%- mbglType(property) %>> propertyValue = { <%- mbglTestValue(property, type) %> };
+<% } -%>
         XCTAssertEqual(rawLayer->get<%- camelize(originalPropertyName(property)) %>(), propertyValue,
                        @"Setting <%- objCName(property) %> to a constant value should update <%- originalPropertyName(property) %>.");
-        XCTAssertEqualObjects(layer.<%- objCName(property) %>, styleValue,
+        XCTAssertEqualObjects(layer.<%- objCName(property) %>, constantStyleValue,
                               @"<%- objCName(property) %> should round-trip constant values.");
 
-        styleValue = [MGLStyleValue<<%- propertyType(property) %>> valueWithStops:@{
-            @18: styleValue,
-        }];
-        layer.<%- objCName(property) %> = styleValue;
-        propertyValue = { mbgl::style::Function<<%- mbglType(property) %>> {
-            {{ 18, propertyValue.asConstant() }},
-            1,
-        }};
+        MGLStyleValue<<%- propertyType(property) %>> * functionStyleValue = [MGLStyleValue<<%- propertyType(property) %>> valueWithInterpolationMode:MGLInterpolationModeInterval cameraStops:@{@18: constantStyleValue} options:nil];
+        layer.<%- objCName(property) %> = functionStyleValue;
+
+        mbgl::style::IntervalStops<<%- mbglType(property) %>> intervalStops = { {{18, <%- mbglTestValue(property, type) %>}} };
+        propertyValue = mbgl::style::CameraFunction<<%- mbglType(property) %>> { intervalStops };
+        
         XCTAssertEqual(rawLayer->get<%- camelize(originalPropertyName(property)) %>(), propertyValue,
-                       @"Setting <%- objCName(property) %> to a function should update <%- originalPropertyName(property) %>.");
-        XCTAssertEqualObjects(layer.<%- objCName(property) %>, styleValue,
-                              @"<%- objCName(property) %> should round-trip functions.");
+                       @"Setting <%- objCName(property) %> to a camera function should update <%- originalPropertyName(property) %>.");
+        XCTAssertEqualObjects(layer.<%- objCName(property) %>, functionStyleValue,
+                              @"<%- objCName(property) %> should round-trip camera functions.");
+
+<% if (property["property-function"]) { -%>
+        functionStyleValue = [MGLStyleValue<<%- propertyType(property) %>> valueWithInterpolationMode:MGLInterpolationModeExponential sourceStops:@{@18: constantStyleValue} attributeName:@"keyName" options:nil];
+        layer.<%- objCName(property) %> = functionStyleValue;
+
+        mbgl::style::ExponentialStops<<%- mbglType(property) %>> exponentialStops = { {{18, <%- mbglTestValue(property, type) %>}}, 1.0 };
+        propertyValue = mbgl::style::SourceFunction<<%- mbglType(property) %>> { "keyName", exponentialStops };
+
+        XCTAssertEqual(rawLayer->get<%- camelize(originalPropertyName(property)) %>(), propertyValue,
+                       @"Setting <%- objCName(property) %> to a source function should update <%- originalPropertyName(property) %>.");
+        XCTAssertEqualObjects(layer.<%- objCName(property) %>, functionStyleValue,
+                              @"<%- objCName(property) %> should round-trip source functions.");
+
+        functionStyleValue = [MGLStyleValue<<%- propertyType(property) %>> valueWithInterpolationMode:MGLInterpolationModeExponential compositeStops:@{@10: @{@18: constantStyleValue}} attributeName:@"keyName" options:nil];
+        layer.<%- objCName(property) %> = functionStyleValue;
+
+        mbgl::style::ExponentialStops<<%- mbglType(property) %>> innerStops = { { {18, <%- mbglTestValue(property, type) %>}}, 1.0 };
+        std::map<float, mbgl::style::ExponentialStops<<%- mbglType(property) %>>> compositeStops = { {10.0, innerStops} };
+
+        propertyValue = mbgl::style::CompositeFunction<<%- mbglType(property) %>> { "keyName", compositeStops };
+
+        XCTAssertEqual(rawLayer->get<%- camelize(originalPropertyName(property)) %>(), propertyValue,
+                       @"Setting <%- objCName(property) %> to a composite function should update <%- originalPropertyName(property) %>.");
+        XCTAssertEqualObjects(layer.<%- objCName(property) %>, functionStyleValue,
+                              @"<%- objCName(property) %> should round-trip composite functions.");                                                                                                          
+<% } -%>                              
 <% if (!property.required) { -%>
 
         layer.<%- objCName(property) %> = nil;
@@ -88,6 +116,14 @@
                       @"Unsetting <%- objCName(property) %> should return <%- originalPropertyName(property) %> to the default value.");
         XCTAssertEqualObjects(layer.<%- objCName(property) %>, defaultStyleValue,
                               @"<%- objCName(property) %> should return the default value after being unset.");
+<% } -%>
+<% if (property["function"] == "piecewise-constant") { -%>
+
+        functionStyleValue = [MGLStyleValue<<%- propertyType(property) %>> valueWithInterpolationMode:MGLInterpolationModeIdentity sourceStops:nil attributeName:@"" options:nil];
+        XCTAssertThrowsSpecificNamed(layer.<%- objCName(property) %> = functionStyleValue, NSException, NSInvalidArgumentException, @"MGLStyleValue should raise an exception if it is applied to a property that cannot support it");
+
+        functionStyleValue = [MGLStyleValue<<%- propertyType(property) %>> valueWithInterpolationMode:MGLInterpolationModeInterval compositeStops:@{@18: constantStyleValue} attributeName:@"" options:nil];
+        XCTAssertThrowsSpecificNamed(layer.<%- objCName(property) %> = functionStyleValue, NSException, NSInvalidArgumentException, @"MGLStyleValue should raise an exception if it is applied to a property that cannot support it");        
 <% } -%>
     }
 <% } -%>

platform/darwin/test/MGLStyleValueTests.swift

@@ -5,8 +5,9 @@ import Mapbox
 extension MGLStyleValueTests {
     
     func testConstantValues() {
-        let shapeSource = MGLShapeSource(identifier: "test", shape: nil, options: nil)
-        let symbolStyleLayer = MGLSymbolStyleLayer(identifier: "test", source: shapeSource)
+        let shapeSource = MGLShapeSource(identifier: "source", shape: nil, options: nil)
+        let symbolStyleLayer = MGLSymbolStyleLayer(identifier: "symbolLayer", source: shapeSource)
+        let circleStyleLayer = MGLCircleStyleLayer(identifier: "circleLayer", source: shapeSource)
         
         // Boolean
         symbolStyleLayer.iconAllowsOverlap = MGLStyleConstantValue(rawValue: true)
@@ -19,20 +20,287 @@ extension MGLStyleValueTests {
         // String
         symbolStyleLayer.text = MGLStyleConstantValue(rawValue: "{name}")
         XCTAssertEqual((symbolStyleLayer.text as! MGLStyleConstantValue<NSString>).rawValue, "{name}")
+
+        var circleTranslationOne = CGVector(dx: 100, dy: 0)
+        let circleTranslationValueOne = NSValue(bytes: &circleTranslationOne, objCType: "{CGVector=dd}")
+
+        // non-data-driven (interpolatable property value), set to constant style value
+        let expectedCircleTranslationValue = MGLStyleValue<NSValue>(rawValue: circleTranslationValueOne)
+        circleStyleLayer.circleTranslation = expectedCircleTranslationValue
+        XCTAssertEqual(circleStyleLayer.circleTranslation, expectedCircleTranslationValue)
+
+        // non-data-driven (enumeration property value), set to constant style value
+        let expectedCircleScaleAlignmentValue = MGLStyleValue<NSValue>(rawValue: NSValue(mglCircleScaleAlignment: .map))
+        circleStyleLayer.circleScaleAlignment = expectedCircleScaleAlignmentValue
+        XCTAssertEqual(circleStyleLayer.circleScaleAlignment, expectedCircleScaleAlignmentValue)
     }
-    
-    func testFunctions() {
+
+    func testDeprecatedFunctions() {
         let shapeSource = MGLShapeSource(identifier: "test", shape: nil, options: nil)
-        let symbolStyleLayer = MGLSymbolStyleLayer(identifier: "test", source: shapeSource)
-        
-        // Boolean
+        let symbolStyleLayer = MGLSymbolStyleLayer(identifier: "symbolLayer", source: shapeSource)
+
+        // deprecated function, stops with float values
+        let iconHaloBlurStyleValue = MGLStyleValue<NSNumber>(interpolationBase: 1.0, stops: [1: MGLStyleValue(rawValue: 0),
+                                                                                             2: MGLStyleValue(rawValue: 1),
+                                                                                             3: MGLStyleValue(rawValue: 2),
+                                                                                             4: MGLStyleValue(rawValue: 3)])
+        symbolStyleLayer.iconHaloBlur = iconHaloBlurStyleValue
+        XCTAssertEqual(symbolStyleLayer.iconHaloBlur!, iconHaloBlurStyleValue)
+
+        // deprecated function, stops with boolean values
         let stops: [NSNumber: MGLStyleValue<NSNumber>] = [
             1: MGLStyleValue(rawValue: true),
             2: MGLStyleValue(rawValue: false),
             3: MGLStyleValue(rawValue: true),
             4: MGLStyleValue(rawValue: false),
+        ]
+        let iconAllowsOverlapStyleValue = MGLStyleValue<NSNumber>(interpolationBase: 1, stops: stops)
+        symbolStyleLayer.iconAllowsOverlap = iconAllowsOverlapStyleValue
+        // iconAllowsOverlap is boolean so mgl and mbgl conversions will coerce the developers stops into interval stops
+        let expectedIconAllowsOverlapStyleValue = MGLStyleValue<NSNumber>(
+            interpolationMode: .interval,
+            cameraStops: stops,
+            options: nil
+        )
+        XCTAssertEqual(symbolStyleLayer.iconAllowsOverlap, expectedIconAllowsOverlapStyleValue)
+    }
+
+    func testFunctionsWithNonDataDrivenProperties() {
+        let shapeSource = MGLShapeSource(identifier: "test", shape: nil, options: nil)
+        let circleStyleLayer = MGLCircleStyleLayer(identifier: "circleLayer", source: shapeSource)
+
+        var circleTranslationOne = CGVector(dx: 100, dy: 0)
+        let circleTranslationValueOne = NSValue(bytes: &circleTranslationOne, objCType: "{CGVector=dd}")
+        var circleTranslationTwo = CGVector(dx: 0, dy: 0)
+        let circleTranslationValueTwo = NSValue(bytes: &circleTranslationTwo, objCType: "{CGVector=dd}")
+
+        let circleTranslationStops = [
+            0: MGLStyleValue<NSValue>(rawValue: circleTranslationValueOne),
+            10: MGLStyleValue<NSValue>(rawValue: circleTranslationValueTwo)
+        ]
+
+        // non-data-driven (interpolatable property value), camera function with CGVector (NSValue) stop values
+        let expectedCircleTranslationValue = MGLStyleValue<NSValue>(
+            interpolationMode: .interval,
+            cameraStops: circleTranslationStops,
+            options: nil
+        )
+        circleStyleLayer.circleTranslation = expectedCircleTranslationValue
+        XCTAssertEqual(circleStyleLayer.circleTranslation, expectedCircleTranslationValue)
+
+        // non-data-driven (enumeration property value), camera function with MGLCircleScaleAlignment enum (NSValue) stop values
+        let scaleAlignmentStops = [
+            0: MGLStyleValue(rawValue: NSValue(mglCircleScaleAlignment: .map)),
+            10: MGLStyleValue(rawValue: NSValue(mglCircleScaleAlignment: .viewport))
+        ]
+        let expectedCircleScaleAlignmentValue = MGLStyleValue<NSValue>(
+            interpolationMode: .interval,
+            cameraStops: scaleAlignmentStops,
+            options: nil
+        )
+        circleStyleLayer.circleScaleAlignment = expectedCircleScaleAlignmentValue
+        XCTAssertEqual(circleStyleLayer.circleScaleAlignment, expectedCircleScaleAlignmentValue)
+    }
+
+    func testFunctionsWithDataDrivenProperties() {
+        let shapeSource = MGLShapeSource(identifier: "test", shape: nil, options: nil)
+        let circleStyleLayer = MGLCircleStyleLayer(identifier: "circleLayer", source: shapeSource)
+
+        #if os(iOS) || os(watchOS) || os(tvOS)
+
+            // data-driven, camera function with exponential color stop values
+            let redGreenStops = [
+                0: MGLStyleValue<UIColor>(rawValue: .red),
+                10: MGLStyleValue<UIColor>(rawValue: .red),
+                15: MGLStyleValue<UIColor>(rawValue: .green)
             ]
-        symbolStyleLayer.iconAllowsOverlap = MGLStyleFunction<NSNumber>(interpolationBase: 1, stops: stops)
-        XCTAssertEqual((symbolStyleLayer.iconAllowsOverlap as! MGLStyleFunction<NSNumber>), MGLStyleFunction(interpolationBase: 1, stops: stops))
+            let expectedCircleColorValue = MGLStyleValue<UIColor>(
+                interpolationMode: .exponential,
+                cameraStops: redGreenStops,
+                options: [.interpolationBase: 10.0]
+            )
+            circleStyleLayer.circleColor = expectedCircleColorValue
+            XCTAssertEqual(circleStyleLayer.circleColor, expectedCircleColorValue)
+
+            // data-driven, source function with categorical color stop values with string attribute keys
+            let redOnlyStops = [
+                "red": MGLStyleValue<UIColor>(rawValue: .red)
+            ]
+            let expectedRedCategoricalValue = MGLStyleValue<UIColor>(
+                interpolationMode: .categorical,
+                sourceStops: redOnlyStops,
+                attributeName: "red",
+                options: [.defaultValue: MGLStyleValue<UIColor>(rawValue: .cyan)]
+            )
+            circleStyleLayer.circleColor = expectedRedCategoricalValue
+            XCTAssertEqual(circleStyleLayer.circleColor, expectedRedCategoricalValue)
+
+            // data-driven, source function with categorical color stop values with integer attribute keys
+            let greenOrangeStops = [
+                0: MGLStyleValue<UIColor>(rawValue: .green),
+                100: MGLStyleValue<UIColor>(rawValue: .orange)
+            ]
+            let expectedGreenOrangeCategoricalValue = MGLStyleValue<UIColor>(
+                interpolationMode: .categorical,
+                sourceStops: greenOrangeStops,
+                attributeName: "temp",
+                options: [.defaultValue: MGLStyleValue<UIColor>(rawValue: .red)]
+            )
+            circleStyleLayer.circleColor = expectedGreenOrangeCategoricalValue
+            XCTAssertEqual(circleStyleLayer.circleColor, expectedGreenOrangeCategoricalValue)
+
+            // data-driven, source function with exponential color stop values
+            let expectedRedGreenSourceExponentialValue = MGLStyleValue<UIColor>(
+                interpolationMode: .exponential,
+                sourceStops: redGreenStops,
+                attributeName: "temp",
+                options: nil
+            )
+            circleStyleLayer.circleColor = expectedRedGreenSourceExponentialValue
+            XCTAssertEqual(circleStyleLayer.circleColor, expectedRedGreenSourceExponentialValue)
+
+            // data-driven, identity source function
+            let expectedSourceIdentityValue = MGLStyleValue<UIColor>(
+                interpolationMode: .identity,
+                sourceStops: nil,
+                attributeName: "size",
+                options: nil
+            )
+            circleStyleLayer.circleColor = expectedSourceIdentityValue
+            XCTAssertEqual(circleStyleLayer.circleColor, expectedSourceIdentityValue)
+
+        #elseif os(macOS)
+
+            // data-driven, camera function with exponential color stop values
+            let redGreenStops = [
+                0: MGLStyleValue<NSColor>(rawValue: .red),
+                10: MGLStyleValue<NSColor>(rawValue: .red),
+                15: MGLStyleValue<NSColor>(rawValue: .green)
+            ]
+            let expectedCircleColorValue = MGLStyleValue<NSColor>(
+                interpolationMode: .exponential,
+                cameraStops: redGreenStops,
+                options: [.interpolationBase: 10.0]
+            )
+            circleStyleLayer.circleColor = expectedCircleColorValue
+            XCTAssertEqual(circleStyleLayer.circleColor, expectedCircleColorValue)
+
+            // data-driven, source function with categorical color stop values with string typed keys
+            let redOnlyStops = [
+                "red": MGLStyleValue<NSColor>(rawValue: .red)
+            ]
+            let expectedRedCategoricalValue = MGLStyleValue<NSColor>(
+                interpolationMode: .categorical,
+
+                sourceStops: redOnlyStops,
+                attributeName: "red",
+                options: [.defaultValue: MGLStyleValue<NSColor>(rawValue: .cyan)]
+            )
+            circleStyleLayer.circleColor = expectedRedCategoricalValue
+            XCTAssertEqual(circleStyleLayer.circleColor, expectedRedCategoricalValue)
+
+            // data-driven, source function with categorical color stop values with integer attribute keys
+            let greenOrangeStops = [
+                0: MGLStyleValue<NSColor>(rawValue: .green),
+                100: MGLStyleValue<NSColor>(rawValue: .orange)
+            ]
+            let expectedGreenOrangeCategoricalValue = MGLStyleValue<NSColor>(
+                interpolationMode: .categorical,
+                sourceStops: greenOrangeStops,
+                attributeName: "temp",
+                options: [.defaultValue: MGLStyleValue<NSColor>(rawValue: .red)]
+            )
+            circleStyleLayer.circleColor = expectedGreenOrangeCategoricalValue
+            XCTAssertEqual(circleStyleLayer.circleColor, expectedGreenOrangeCategoricalValue)
+
+            // data-driven, source function with exponential color stop values
+            let expectedRedGreenSourceExponentialValue = MGLStyleValue<NSColor>(
+                interpolationMode: .exponential,
+                sourceStops: redGreenStops,
+                attributeName: "temp",
+                options: nil
+            )
+            circleStyleLayer.circleColor = expectedRedGreenSourceExponentialValue
+            XCTAssertEqual(circleStyleLayer.circleColor, expectedRedGreenSourceExponentialValue)
+
+            // data-driven, identity source function
+            let expectedSourceIdentityValue = MGLStyleValue<NSColor>(
+                interpolationMode: .identity,
+                sourceStops: nil,
+                attributeName: "size",
+                options: nil
+            )
+            circleStyleLayer.circleColor = expectedSourceIdentityValue
+            XCTAssertEqual(circleStyleLayer.circleColor, expectedSourceIdentityValue)
+
+        #endif
+
+        // data-driven, source function with categorical color stop values with boolean attribute keys
+        let booleanCategoricalStops = [
+            false: MGLStyleValue<NSNumber>(rawValue: 0),
+            true: MGLStyleValue<NSNumber>(rawValue: 2)
+        ]
+        let expectedCircleBlurCategoricalValue = MGLStyleValue<NSNumber>(
+            interpolationMode: .categorical,
+            sourceStops: booleanCategoricalStops,
+            attributeName: "fuzzy",
+            options: [.defaultValue: MGLStyleValue<NSNumber>(rawValue: 42)]
+        )
+        circleStyleLayer.circleBlur = expectedCircleBlurCategoricalValue
+        XCTAssertEqual(circleStyleLayer.circleBlur, expectedCircleBlurCategoricalValue)
+
+        // data-driven, composite function with inner categorical color stop values with string attribute keys nested in outer camera stops
+        let smallRadius = MGLStyleValue<NSNumber>(rawValue: 5)
+        let mediumRadius = MGLStyleValue<NSNumber>(rawValue: 10)
+        let largeRadius = MGLStyleValue<NSNumber>(rawValue: 20)
+        let radiusCompositeCategoricalStops: [NSNumber: [String: MGLStyleValue<NSNumber>]] = [
+            0: ["green": smallRadius],
+            10: ["green": smallRadius],
+            15: ["green": largeRadius],
+            20: ["green": largeRadius]
+        ]
+        let defaultRadius = MGLStyleValue<NSNumber>(rawValue: 2)
+        let expectedCompositeCategoricalValue = MGLStyleValue<NSNumber>(
+            interpolationMode: .categorical,
+            compositeStops: radiusCompositeCategoricalStops,
+            attributeName: "color",
+            options: [.defaultValue: defaultRadius]
+        )
+        circleStyleLayer.circleRadius = expectedCompositeCategoricalValue
+        XCTAssertEqual(circleStyleLayer.circleRadius, expectedCompositeCategoricalValue)
+
+        // data-driven, composite function with inner exponential color stop values nested in outer camera stops
+        let radiusCompositeExponentialOrIntervalStops: [NSNumber: [NSNumber: MGLStyleValue<NSNumber>]] = [
+            0: [0: smallRadius],
+            10: [200: smallRadius],
+            20: [200: largeRadius]
+        ]
+        let expectedCompositeExponentialValue = MGLStyleValue<NSNumber>(
+            interpolationMode: .exponential,
+            compositeStops: radiusCompositeExponentialOrIntervalStops,
+            attributeName: "temp",
+            options: [.defaultValue: mediumRadius]
+        )
+        circleStyleLayer.circleRadius = expectedCompositeExponentialValue
+        XCTAssertEqual(circleStyleLayer.circleRadius, expectedCompositeExponentialValue)
+
+        // get a value back
+        if let returnedCircleRadius = circleStyleLayer.circleRadius as? MGLCompositeStyleFunction<NSNumber> {
+            if let returnedStops = returnedCircleRadius.stops as NSDictionary? as? [NSNumber: [NSNumber: MGLStyleValue<NSNumber>]] {
+                let lhs: MGLStyleValue<NSNumber> = returnedStops[0]!.values.first!
+                let rhs: MGLStyleValue<NSNumber> = radiusCompositeExponentialOrIntervalStops[0]!.values.first!
+                XCTAssertEqual(lhs, rhs)
+            }
+        }
+
+        // data-driven, composite function with inner interval color stop values nested in outer camera stops
+        let expectedCompositeIntervalValue = MGLStyleValue<NSNumber>(
+            interpolationMode: .interval,
+            compositeStops: radiusCompositeExponentialOrIntervalStops,
+            attributeName: "temp",
+            options: nil
+        )
+        circleStyleLayer.circleRadius = expectedCompositeIntervalValue
+        XCTAssertEqual(circleStyleLayer.circleRadius, expectedCompositeIntervalValue)
     }
 }

platform/ios/app/MBXViewController.m

@@ -6,8 +6,6 @@
 #import "MBXAnnotationView.h"
 #import "MBXUserLocationAnnotationView.h"
 
-#import "MGLFillStyleLayer.h"
-
 #import <Mapbox/Mapbox.h>
 
 #import <objc/runtime.h>
@@ -72,6 +70,7 @@ typedef NS_ENUM(NSInteger, MBXSettingsRuntimeStylingRows) {
     MBXSettingsRuntimeStylingRasterSource,
     MBXSettingsRuntimeStylingCountryLabels,
     MBXSettingsRuntimeStylingRouteLine,
+    MBXSettingsRuntimeStylingDDSPolygon,
 };
 
 typedef NS_ENUM(NSInteger, MBXSettingsMiscellaneousRows) {
@@ -336,6 +335,7 @@ typedef NS_ENUM(NSInteger, MBXSettingsMiscellaneousRows) {
                 @"Style Raster Source",
                 [NSString stringWithFormat:@"Label Countries in %@", (_usingLocaleBasedCountryLabels ? @"Local Language" : [[NSLocale currentLocale] displayNameForKey:NSLocaleIdentifier value:[self bestLanguageForUser]])],
                 @"Add Route Line",
+                @"Dynamically Style Polygon",
             ]];
             break;
         case MBXSettingsMiscellaneous:
@@ -497,6 +497,9 @@ typedef NS_ENUM(NSInteger, MBXSettingsMiscellaneousRows) {
                 case MBXSettingsRuntimeStylingRouteLine:
                     [self styleRouteLine];
                     break;
+                case MBXSettingsRuntimeStylingDDSPolygon:
+                    [self stylePolygonWithDDS];
+                    break;
                 default:
                     NSAssert(NO, @"All runtime styling setting rows should be implemented");
                     break;
@@ -739,22 +742,24 @@ typedef NS_ENUM(NSInteger, MBXSettingsMiscellaneousRows) {
 - (void)styleWaterLayer
 {
     MGLFillStyleLayer *waterLayer = (MGLFillStyleLayer *)[self.mapView.style layerWithIdentifier:@"water"];
-    MGLStyleValue *waterColorFunction = [MGLStyleValue<UIColor *> valueWithStops:@{
-        @6.0f: [MGLStyleValue<UIColor *> valueWithRawValue:[UIColor yellowColor]],
-        @8.0f: [MGLStyleValue<UIColor *> valueWithRawValue:[UIColor blueColor]],
-        @10.0f: [MGLStyleValue<UIColor *> valueWithRawValue:[UIColor redColor]],
-        @12.0f: [MGLStyleValue<UIColor *> valueWithRawValue:[UIColor greenColor]],
-        @14.0f: [MGLStyleValue<UIColor *> valueWithRawValue:[UIColor blueColor]],
-    }];
+    NSDictionary *waterColorStops = @{@6.0f: [MGLStyleValue<UIColor *> valueWithRawValue:[UIColor yellowColor]],
+                                      @8.0f: [MGLStyleValue<UIColor *> valueWithRawValue:[UIColor blueColor]],
+                                      @10.0f: [MGLStyleValue<UIColor *> valueWithRawValue:[UIColor redColor]],
+                                      @12.0f: [MGLStyleValue<UIColor *> valueWithRawValue:[UIColor greenColor]],
+                                      @14.0f: [MGLStyleValue<UIColor *> valueWithRawValue:[UIColor blueColor]]};
+    MGLStyleValue *waterColorFunction = [MGLStyleValue<UIColor *> valueWithInterpolationMode:MGLInterpolationModeExponential
+                                                                                 cameraStops:waterColorStops
+                                                                                     options: nil];
     waterLayer.fillColor = waterColorFunction;
 
-    MGLStyleValue *fillAntialiasedFunction = [MGLStyleValue<NSNumber *> valueWithStops:@{
-        @11: [MGLStyleValue<NSNumber *> valueWithRawValue:@YES],
-        @12: [MGLStyleValue<NSNumber *> valueWithRawValue:@NO],
-        @13: [MGLStyleValue<NSNumber *> valueWithRawValue:@YES],
-        @14: [MGLStyleValue<NSNumber *> valueWithRawValue:@NO],
-        @15: [MGLStyleValue<NSNumber *> valueWithRawValue:@YES],
-    }];
+    NSDictionary *fillAntialiasedStops = @{@11: [MGLStyleValue<NSNumber *> valueWithRawValue:@YES],
+                                           @12: [MGLStyleValue<NSNumber *> valueWithRawValue:@NO],
+                                           @13: [MGLStyleValue<NSNumber *> valueWithRawValue:@YES],
+                                           @14: [MGLStyleValue<NSNumber *> valueWithRawValue:@NO],
+                                           @15: [MGLStyleValue<NSNumber *> valueWithRawValue:@YES]};
+    MGLStyleValue *fillAntialiasedFunction = [MGLStyleValue<NSNumber *> valueWithInterpolationMode:MGLInterpolationModeInterval
+                                                                                       cameraStops:fillAntialiasedStops
+                                                                                           options:nil];
     waterLayer.fillAntialiased = fillAntialiasedFunction;
 }
 
@@ -763,21 +768,23 @@ typedef NS_ENUM(NSInteger, MBXSettingsMiscellaneousRows) {
     MGLLineStyleLayer *roadLayer = (MGLLineStyleLayer *)[self.mapView.style layerWithIdentifier:@"road-primary"];
     roadLayer.lineColor = [MGLStyleValue<UIColor *> valueWithRawValue:[UIColor blackColor]];
 
-    MGLStyleValue *lineWidthFunction = [MGLStyleValue<NSNumber *> valueWithStops:@{
-       @5: [MGLStyleValue<NSNumber *> valueWithRawValue:@5],
-       @10: [MGLStyleValue<NSNumber *> valueWithRawValue:@15],
-       @15: [MGLStyleValue<NSNumber *> valueWithRawValue:@30],
-    }];
-
-    MGLStyleValue *roadLineColor = [MGLStyleValue<UIColor *> valueWithStops:@{
-        @10: [MGLStyleValue<UIColor *> valueWithRawValue:[UIColor purpleColor]],
-        @13: [MGLStyleValue<UIColor *> valueWithRawValue:[UIColor yellowColor]],
-        @16: [MGLStyleValue<UIColor *> valueWithRawValue:[UIColor cyanColor]],
-    }];
-    roadLayer.lineColor = roadLineColor;
+    NSDictionary *lineWidthStops = @{@5: [MGLStyleValue<NSNumber *> valueWithRawValue:@5],
+                                     @10: [MGLStyleValue<NSNumber *> valueWithRawValue:@15],
+                                     @15: [MGLStyleValue<NSNumber *> valueWithRawValue:@30]};
+    MGLStyleValue *lineWidthFunction = [MGLStyleValue<NSNumber *> valueWithInterpolationMode:MGLInterpolationModeExponential
+                                                                                 cameraStops:lineWidthStops
+                                                                                     options:nil];
     roadLayer.lineWidth = lineWidthFunction;
     roadLayer.lineGapWidth = lineWidthFunction;
 
+    NSDictionary *roadLineColorStops = @{@10: [MGLStyleValue<UIColor *> valueWithRawValue:[UIColor purpleColor]],
+                                         @13: [MGLStyleValue<UIColor *> valueWithRawValue:[UIColor yellowColor]],
+                                         @16: [MGLStyleValue<UIColor *> valueWithRawValue:[UIColor cyanColor]]};
+    MGLStyleValue *roadLineColor = [MGLStyleValue<UIColor *> valueWithInterpolationMode:MGLInterpolationModeExponential
+                                                                            cameraStops:roadLineColorStops
+                                                                                options: nil];
+    roadLayer.lineColor = roadLineColor;
+
     roadLayer.visible = YES;
     roadLayer.maximumZoomLevel = 15;
     roadLayer.minimumZoomLevel = 13;
@@ -790,10 +797,10 @@ typedef NS_ENUM(NSInteger, MBXSettingsMiscellaneousRows) {
     [self.mapView.style addSource:rasterSource];
 
     MGLRasterStyleLayer *rasterLayer = [[MGLRasterStyleLayer alloc] initWithIdentifier:@"my-raster-layer" source:rasterSource];
-    MGLStyleValue *opacityFunction = [MGLStyleValue<NSNumber *> valueWithStops:@{
-        @20.0f: [MGLStyleValue<NSNumber *> valueWithRawValue:@1.0f],
-        @5.0f: [MGLStyleValue<NSNumber *> valueWithRawValue:@0.0f],
-    }];
+    MGLStyleValue *opacityFunction = [MGLStyleValue<NSNumber *> valueWithInterpolationMode:MGLInterpolationModeExponential
+                                                                               cameraStops:@{@20.0f: [MGLStyleValue<NSNumber *> valueWithRawValue:@1.0f],
+                                                                                             @5.0f: [MGLStyleValue<NSNumber *> valueWithRawValue:@0.0f]}
+                                                                                   options:nil];
     rasterLayer.rasterOpacity = opacityFunction;
     [self.mapView.style addLayer:rasterLayer];
 }
@@ -822,7 +829,7 @@ typedef NS_ENUM(NSInteger, MBXSettingsMiscellaneousRows) {
     self.mapView.style.transitionDuration = 5;
     self.mapView.style.transitionDelay = 1;
     MGLFillStyleLayer *buildingLayer = (MGLFillStyleLayer *)[self.mapView.style layerWithIdentifier:@"building"];
-    buildingLayer.fillColor = [MGLStyleValue<UIColor *> valueWithRawValue:[UIColor blackColor]];
+    buildingLayer.fillColor = [MGLStyleValue<UIColor *> valueWithRawValue:[UIColor purpleColor]];
 }
 
 - (void)styleFerryLayer
@@ -857,18 +864,6 @@ typedef NS_ENUM(NSInteger, MBXSettingsMiscellaneousRows) {
     });
 }
 
-+ (MGLStyleConstantValue<NSValue *> *)testEnum:(NSUInteger)value type:(const char *)type
-{
-    return [MGLStyleConstantValue<NSValue *> valueWithRawValue:[NSValue value:&value withObjCType:type]];
-}
-
-+ (MGLStyleFunction<NSValue *> *)testEnumFunction:(NSUInteger)value type:(const char *)type
-{
-    return [MGLStyleFunction<NSValue *> valueWithStops:@{
-                                                         @18: [self testEnum:value type:type],
-                                                         }];
-}
-
 - (void)styleFilteredLines
 {
     // set style and focus on lower 48
@@ -1204,6 +1199,48 @@ typedef NS_ENUM(NSInteger, MBXSettingsMiscellaneousRows) {
     [self.mapView.style addLayer:routeLayer];
 }
 
+- (void)stylePolygonWithDDS {
+    CLLocationCoordinate2D leftCoords[] = {
+        {37.73081027834234, -122.49412536621094},
+        {37.7566013348511, -122.49412536621094},
+        {37.7566013348511, -122.46253967285156},
+        {37.73081027834234, -122.46253967285156},
+        {37.73081027834234, -122.49412536621094},
+    };
+    CLLocationCoordinate2D rightCoords[] = {
+        {37.73135334055843, -122.44640350341795},
+        {37.75741564287944, -122.44640350341795},
+        {37.75741564287944, -122.41310119628906},
+        {37.73135334055843, -122.41310119628906},
+        {37.73135334055843, -122.44640350341795},
+    };
+    MGLPolygonFeature *leftFeature = [MGLPolygonFeature polygonWithCoordinates:leftCoords count:5];
+    leftFeature.attributes = @{@"fill": @(YES)};
+
+    MGLPolygonFeature *rightFeature = [MGLPolygonFeature polygonWithCoordinates:rightCoords count:5];
+    rightFeature.attributes = @{@"opacity": @(0.5)};
+
+    MGLShapeSource *shapeSource = [[MGLShapeSource alloc] initWithIdentifier:@"shape-source" features:@[leftFeature, rightFeature] options:nil];
+    [self.mapView.style addSource:shapeSource];
+
+    // source, categorical function that sets any feature with a "fill" attribute value of true to red color and anything without to green
+    MGLFillStyleLayer *fillStyleLayer = [[MGLFillStyleLayer alloc] initWithIdentifier:@"fill-layer" source:shapeSource];
+    NSDictionary *stops = @{@(YES): [MGLStyleValue<UIColor *> valueWithRawValue:[UIColor greenColor]]};
+    NSDictionary *fillColorOptions = @{MGLStyleFunctionOptionDefaultValue: [MGLStyleValue<UIColor *> valueWithRawValue:[UIColor redColor]]};
+    fillStyleLayer.fillColor = [MGLStyleValue<UIColor *> valueWithInterpolationMode:MGLInterpolationModeCategorical
+                                                                        sourceStops:stops
+                                                                      attributeName:@"fill"
+                                                                            options:fillColorOptions];
+
+    // source, identity function that sets any feature with an "opacity" attribute to use that value and anything without to 1.0
+    NSDictionary *fillOpacityOptions = @{MGLStyleFunctionOptionDefaultValue: [MGLStyleValue<NSNumber *> valueWithRawValue:@(1.0)]};
+    fillStyleLayer.fillOpacity = [MGLStyleValue<NSNumber *> valueWithInterpolationMode:MGLInterpolationModeIdentity
+                                                                           sourceStops:nil
+                                                                         attributeName:@"opacity"
+                                                                               options:fillOpacityOptions];
+    [self.mapView.style addLayer:fillStyleLayer];
+}
+
 - (void)styleLabelLanguageForLayersNamed:(NSArray<NSString *> *)layers
 {
     _usingLocaleBasedCountryLabels = !_usingLocaleBasedCountryLabels;
@@ -1219,8 +1256,9 @@ typedef NS_ENUM(NSInteger, MBXSettingsMiscellaneousRows) {
                 if ([label.rawValue hasPrefix:@"{name"]) {
                     layer.text = [MGLStyleValue valueWithRawValue:language];
                 }
-            } else if ([layer.text isKindOfClass:[MGLStyleFunction class]]) {
-                MGLStyleFunction *function = (MGLStyleFunction<NSString *> *)layer.text;
+            }
+            else if ([layer.text isKindOfClass:[MGLCameraStyleFunction class]]) {
+                MGLCameraStyleFunction *function = (MGLCameraStyleFunction<NSString *> *)layer.text;
                 [function.stops enumerateKeysAndObjectsUsingBlock:^(id zoomLevel, id stop, BOOL *done) {
                     if ([stop isKindOfClass:[MGLStyleConstantValue class]]) {
                         MGLStyleConstantValue *label = (MGLStyleConstantValue<NSString *> *)stop;

platform/ios/ios.xcodeproj/project.pbxproj

@@ -906,8 +906,8 @@
 				DA72620A1DEEE3480043BB89 /* MGLOpenGLStyleLayer.mm */,
 				353933FA1D3FB7C0003F57D7 /* MGLRasterStyleLayer.h */,
 				35136D411D42274500C20EFD /* MGLRasterStyleLayer.mm */,
-				35D13AB51D3D15E300AFB4E0 /* MGLStyleLayer.h */,
 				35E79F1F1D41266300957B9E /* MGLStyleLayer_Private.h */,
+				35D13AB51D3D15E300AFB4E0 /* MGLStyleLayer.h */,
 				35D13AB61D3D15E300AFB4E0 /* MGLStyleLayer.mm */,
 				353933FD1D3FB7DD003F57D7 /* MGLSymbolStyleLayer.h */,
 				35136D441D42275100C20EFD /* MGLSymbolStyleLayer.mm */,

platform/macos/app/MapDocument.m

@@ -373,8 +373,9 @@ NS_ARRAY_OF(id <MGLAnnotation>) *MBXFlattenedShapes(NS_ARRAY_OF(id <MGLAnnotatio
         if ([layer.text isKindOfClass:[MGLStyleConstantValue class]]) {
             NSString *textField = [(MGLStyleConstantValue<NSString *> *)layer.text rawValue];
             layer.text = [MGLStyleValue<NSString *> valueWithRawValue:stringByLocalizingString(textField)];
-        } else if ([layer.text isKindOfClass:[MGLStyleFunction class]]) {
-            MGLStyleFunction *function = (MGLStyleFunction<NSString *> *)layer.text;
+        }
+        else if ([layer.text isKindOfClass:[MGLCameraStyleFunction class]]) {
+            MGLCameraStyleFunction *function = (MGLCameraStyleFunction<NSString *> *)layer.text;
             NSMutableDictionary *stops = function.stops.mutableCopy;
             [stops enumerateKeysAndObjectsUsingBlock:^(NSNumber *zoomLevel, MGLStyleConstantValue<NSString *> *stop, BOOL *done) {
                 NSString *textField = stop.rawValue;