[ios, macos] Update test coverage for expression's convenient methods.

author: Fabian Guerra <fabian.guerra@mapbox.com> 2018-03-09 18:27:05 -0500
committer: Fabian Guerra <fabian.guerra@mapbox.com> 2018-03-16 18:19:49 -0400
commit: 51e8894352253b49b05bd5bd2cfc309f6b9bb20e (patch)
tree: cf8db10565145df11087d63578796405dad53cf4
parent: b37f422785b3e2cc66b9a3d6d43747381f6ac6f4 (diff)
download: qtlocation-mapboxgl-51e8894352253b49b05bd5bd2cfc309f6b9bb20e.tar.gz
15 files changed, 193 insertions, 135 deletions
diff --git a/platform/darwin/scripts/generate-style-code.js b/platform/darwin/scripts/generate-style-code.js
index 54178a54ec..1f7596690f 100755
--- a/platform/darwin/scripts/generate-style-code.js
+++ b/platform/darwin/scripts/generate-style-code.js
@@ -586,7 +586,7 @@ global.objCExpressionAdditionsTestValue = function (property) {
         case 'number':
             return '@0xff';
         case 'string':
-            return `@"'${_.startCase(propertyName)}'"`;
+            return `@"${_.startCase(propertyName)}"`;
         case 'color':
             return '[MGLColor redColor]';
         default:
diff --git a/platform/darwin/src/NSExpression+MGLAdditions.h b/platform/darwin/src/NSExpression+MGLAdditions.h
index 9b74460e47..a29a828db7 100644
--- a/platform/darwin/src/NSExpression+MGLAdditions.h
+++ b/platform/darwin/src/NSExpression+MGLAdditions.h
@@ -10,7 +10,7 @@
 NS_ASSUME_NONNULL_BEGIN
 
 typedef NSString *MGLExpressionStyleFunction NS_STRING_ENUM;
-typedef NSString *MGLExpressionInterpolationMode NS_STRING_ENUM;
+typedef NSString *MGLExpressionInterpolationMode NS_TYPED_EXTENSIBLE_ENUM;
 
 /**
  An `NSString` identifying the `zoomLevel` operator in an `NSExpression`.
@@ -93,7 +93,7 @@ extern MGL_EXPORT const MGLExpressionInterpolationMode MGLExpressionInterpolatio
 /**
  Returns a constant expression containing an `NSString`.
  
- This is equivalent to call `[NSExpression expressionForConstant:]`.
+ This is equivalent to call `[NSExpression expressionForConstantValue:]`.
  
  @param string The string constant.
  */
@@ -102,7 +102,7 @@ extern MGL_EXPORT const MGLExpressionInterpolationMode MGLExpressionInterpolatio
 /**
  Returns a constant expression containing an `MGLColor`.
  
- This is equivalent to call `[NSExpression expressionForConstant:]`.
+ This is equivalent to call `[NSExpression expressionForConstantValue:]`.
  
  @param color The color constant.
  */
@@ -111,7 +111,7 @@ extern MGL_EXPORT const MGLExpressionInterpolationMode MGLExpressionInterpolatio
 /**
  Returns a constant expression containing an `NSValue`.
  
- This is equivalent to call `[NSExpression expressionForConstant:]`.
+ This is equivalent to call `[NSExpression expressionForConstantValue:]`.
  
  @param value The value constant.
  */
diff --git a/platform/darwin/src/NSExpression+MGLAdditions.mm b/platform/darwin/src/NSExpression+MGLAdditions.mm
index a7a2f0e1bb..62fddd8f86 100644
--- a/platform/darwin/src/NSExpression+MGLAdditions.mm
+++ b/platform/darwin/src/NSExpression+MGLAdditions.mm
@@ -13,8 +13,8 @@
 
 #import <mbgl/style/expression/expression.hpp>
 
-const MGLExpressionStyleFunction MGLExpressionStyleFunctionZoomLevel = @"$zoomLevel";
-const MGLExpressionStyleFunction MGLExpressionStyleFunctionHeatmapDensity = @"$heatmapDensity";
+const MGLExpressionStyleFunction MGLExpressionStyleFunctionZoomLevel = @"zoomLevel";
+const MGLExpressionStyleFunction MGLExpressionStyleFunctionHeatmapDensity = @"heatmapDensity";
 
 const MGLExpressionInterpolationMode MGLExpressionInterpolationModeLinear = @"linear";
 const MGLExpressionInterpolationMode MGLExpressionInterpolationModeExponential = @"exponential";
@@ -305,7 +305,7 @@ NSArray *MGLSubexpressionsWithJSONObjects(NSArray *objects) {
 }
 
 + (instancetype)mgl_expressionForString:(NSString *)string {
-    return [NSExpression expressionWithFormat:string];
+    return [NSExpression expressionForConstantValue:string];
 }
 
 + (instancetype)mgl_expressionForColor:(MGLColor *)color {
@@ -333,19 +333,19 @@ NSArray *MGLSubexpressionsWithJSONObjects(NSArray *objects) {
 }
 
 + (instancetype)mgl_expressionForStepFunction:(MGLExpressionStyleFunction)function defaultValue:(NSValue *)value stops:(nonnull NS_DICTIONARY_OF(NSNumber *, id) *)stops {
-    return [NSExpression mgl_expressionForStepFunction:[NSExpression mgl_expressionForString:function]
+    return [NSExpression mgl_expressionForStepFunction:[NSExpression expressionForVariable:function]
                                      defaultExpression:[NSExpression mgl_expressionForValue:value]
                                                  stops:[NSExpression expressionWithFormat:@"%@", stops]];
 }
 
 + (instancetype)mgl_expressionForStepFunction:(MGLExpressionStyleFunction)function defaultString:(NSString *)string stops:(nonnull NS_DICTIONARY_OF(NSNumber *, id) *)stops {
-    return [NSExpression mgl_expressionForStepFunction:[NSExpression mgl_expressionForString:function]
+    return [NSExpression mgl_expressionForStepFunction:[NSExpression expressionForVariable:function]
                                      defaultExpression:[NSExpression mgl_expressionForString:string]
                                                  stops:[NSExpression expressionWithFormat:@"%@", stops]];
 }
 
 + (instancetype)mgl_expressionForStepFunction:(MGLExpressionStyleFunction)function defaultColor:(MGLColor *)color stops:(nonnull NS_DICTIONARY_OF(NSNumber *, id) *)stops {
-    return [NSExpression mgl_expressionForStepFunction:[NSExpression mgl_expressionForString:function]
+    return [NSExpression mgl_expressionForStepFunction:[NSExpression expressionForVariable:function]
                                      defaultExpression:[NSExpression mgl_expressionForColor:color]
                                                  stops:[NSExpression expressionWithFormat:@"%@", stops]];
 }
@@ -355,7 +355,7 @@ NSArray *MGLSubexpressionsWithJSONObjects(NSArray *objects) {
 }
 
 + (instancetype)mgl_expressionForInterpolateFunction:(MGLExpressionStyleFunction)function curveType:(nonnull MGLExpressionInterpolationMode)curveType steps:(nonnull NS_DICTIONARY_OF(NSNumber *, id) *)steps; {
-    return [NSExpression mgl_expressionForInterpolateFunction:[NSExpression mgl_expressionForString:function]
+    return [NSExpression mgl_expressionForInterpolateFunction:[NSExpression expressionForVariable:function]
                                                     curveType:curveType
                                                    parameters:nil
                                                         steps:[NSExpression expressionWithFormat:@"%@", steps]];
diff --git a/platform/darwin/test/MGLBackgroundStyleLayerTests.mm b/platform/darwin/test/MGLBackgroundStyleLayerTests.mm
index 7c351463cc..897ab22c4a 100644
--- a/platform/darwin/test/MGLBackgroundStyleLayerTests.mm
+++ b/platform/darwin/test/MGLBackgroundStyleLayerTests.mm
@@ -42,7 +42,7 @@
                               @"backgroundColor should round-trip constant value expressions.");
 
         constantExpression = [NSExpression mgl_expressionForColor:[MGLColor redColor]];
-        NSExpression *functionExpression = [NSExpression mgl_expressionForStepFunction:[NSExpression mgl_expressionForString:MGLExpressionStyleFunctionZoomLevel]
+        NSExpression *functionExpression = [NSExpression mgl_expressionForStepFunction:[NSExpression expressionForVariable:MGLExpressionStyleFunctionZoomLevel]
                                                                      defaultExpression:constantExpression
                                                                                  stops:[NSExpression expressionWithFormat:@"%@", @{@18: constantExpression}]];
         layer.backgroundColor = functionExpression;
@@ -100,7 +100,7 @@
                               @"backgroundOpacity should round-trip constant value expressions.");
 
         constantExpression = [NSExpression mgl_expressionForValue:@0xff];
-        NSExpression *functionExpression = [NSExpression mgl_expressionForStepFunction:[NSExpression mgl_expressionForString:MGLExpressionStyleFunctionZoomLevel]
+        NSExpression *functionExpression = [NSExpression mgl_expressionForStepFunction:[NSExpression expressionForVariable:MGLExpressionStyleFunctionZoomLevel]
                                                                      defaultExpression:constantExpression
                                                                                  stops:[NSExpression expressionWithFormat:@"%@", @{@18: constantExpression}]];
         layer.backgroundOpacity = functionExpression;
@@ -149,7 +149,7 @@
                       @"background-pattern should be unset initially.");
         NSExpression *defaultExpression = layer.backgroundPattern;
 
-        NSExpression *constantExpression = [NSExpression mgl_expressionForString:@"'Background Pattern'"];
+        NSExpression *constantExpression = [NSExpression mgl_expressionForString:@"Background Pattern"];
         layer.backgroundPattern = constantExpression;
         mbgl::style::PropertyValue<std::string> propertyValue = { "Background Pattern" };
         XCTAssertEqual(rawLayer->getBackgroundPattern(), propertyValue,
@@ -157,8 +157,8 @@
         XCTAssertEqualObjects(layer.backgroundPattern, constantExpression,
                               @"backgroundPattern should round-trip constant value expressions.");
 
-        constantExpression = [NSExpression mgl_expressionForString:@"'Background Pattern'"];
-        NSExpression *functionExpression = [NSExpression mgl_expressionForStepFunction:[NSExpression mgl_expressionForString:MGLExpressionStyleFunctionZoomLevel]
+        constantExpression = [NSExpression mgl_expressionForString:@"Background Pattern"];
+        NSExpression *functionExpression = [NSExpression mgl_expressionForStepFunction:[NSExpression expressionForVariable:MGLExpressionStyleFunctionZoomLevel]
                                                                      defaultExpression:constantExpression
                                                                                  stops:[NSExpression expressionWithFormat:@"%@", @{@18: constantExpression}]];
         layer.backgroundPattern = functionExpression;
diff --git a/platform/darwin/test/MGLCircleStyleLayerTests.mm b/platform/darwin/test/MGLCircleStyleLayerTests.mm
index 1e9bcf8f97..0917cee737 100644
--- a/platform/darwin/test/MGLCircleStyleLayerTests.mm
+++ b/platform/darwin/test/MGLCircleStyleLayerTests.mm
@@ -63,7 +63,7 @@
                               @"circleBlur should round-trip constant value expressions.");
 
         constantExpression = [NSExpression mgl_expressionForValue:@0xff];
-        NSExpression *functionExpression = [NSExpression mgl_expressionForStepFunction:[NSExpression mgl_expressionForString:MGLExpressionStyleFunctionZoomLevel]
+        NSExpression *functionExpression = [NSExpression mgl_expressionForStepFunction:[NSExpression expressionForVariable:MGLExpressionStyleFunctionZoomLevel]
                                                                      defaultExpression:constantExpression
                                                                                  stops:[NSExpression expressionWithFormat:@"%@", @{@18: constantExpression}]];
         layer.circleBlur = functionExpression;
@@ -140,7 +140,7 @@
                               @"circleColor should round-trip constant value expressions.");
 
         constantExpression = [NSExpression mgl_expressionForColor:[MGLColor redColor]];
-        NSExpression *functionExpression = [NSExpression mgl_expressionForStepFunction:[NSExpression mgl_expressionForString:MGLExpressionStyleFunctionZoomLevel]
+        NSExpression *functionExpression = [NSExpression mgl_expressionForStepFunction:[NSExpression expressionForVariable:MGLExpressionStyleFunctionZoomLevel]
                                                                      defaultExpression:constantExpression
                                                                                  stops:[NSExpression expressionWithFormat:@"%@", @{@18: constantExpression}]];
         layer.circleColor = functionExpression;
@@ -217,7 +217,7 @@
                               @"circleOpacity should round-trip constant value expressions.");
 
         constantExpression = [NSExpression mgl_expressionForValue:@0xff];
-        NSExpression *functionExpression = [NSExpression mgl_expressionForStepFunction:[NSExpression mgl_expressionForString:MGLExpressionStyleFunctionZoomLevel]
+        NSExpression *functionExpression = [NSExpression mgl_expressionForStepFunction:[NSExpression expressionForVariable:MGLExpressionStyleFunctionZoomLevel]
                                                                      defaultExpression:constantExpression
                                                                                  stops:[NSExpression expressionWithFormat:@"%@", @{@18: constantExpression}]];
         layer.circleOpacity = functionExpression;
@@ -294,7 +294,7 @@
                               @"circlePitchAlignment should round-trip constant value expressions.");
 
         constantExpression = [NSExpression expressionWithFormat:@"'viewport'"];
-        NSExpression *functionExpression = [NSExpression mgl_expressionForStepFunction:[NSExpression mgl_expressionForString:MGLExpressionStyleFunctionZoomLevel]
+        NSExpression *functionExpression = [NSExpression mgl_expressionForStepFunction:[NSExpression expressionForVariable:MGLExpressionStyleFunctionZoomLevel]
                                                                      defaultExpression:constantExpression
                                                                                  stops:[NSExpression expressionWithFormat:@"%@", @{@18: constantExpression}]];
         layer.circlePitchAlignment = functionExpression;
@@ -343,7 +343,7 @@
                               @"circleRadius should round-trip constant value expressions.");
 
         constantExpression = [NSExpression mgl_expressionForValue:@0xff];
-        NSExpression *functionExpression = [NSExpression mgl_expressionForStepFunction:[NSExpression mgl_expressionForString:MGLExpressionStyleFunctionZoomLevel]
+        NSExpression *functionExpression = [NSExpression mgl_expressionForStepFunction:[NSExpression expressionForVariable:MGLExpressionStyleFunctionZoomLevel]
                                                                      defaultExpression:constantExpression
                                                                                  stops:[NSExpression expressionWithFormat:@"%@", @{@18: constantExpression}]];
         layer.circleRadius = functionExpression;
@@ -420,7 +420,7 @@
                               @"circleScaleAlignment should round-trip constant value expressions.");
 
         constantExpression = [NSExpression expressionWithFormat:@"'viewport'"];
-        NSExpression *functionExpression = [NSExpression mgl_expressionForStepFunction:[NSExpression mgl_expressionForString:MGLExpressionStyleFunctionZoomLevel]
+        NSExpression *functionExpression = [NSExpression mgl_expressionForStepFunction:[NSExpression expressionForVariable:MGLExpressionStyleFunctionZoomLevel]
                                                                      defaultExpression:constantExpression
                                                                                  stops:[NSExpression expressionWithFormat:@"%@", @{@18: constantExpression}]];
         layer.circleScaleAlignment = functionExpression;
@@ -469,7 +469,7 @@
                               @"circleStrokeColor should round-trip constant value expressions.");
 
         constantExpression = [NSExpression mgl_expressionForColor:[MGLColor redColor]];
-        NSExpression *functionExpression = [NSExpression mgl_expressionForStepFunction:[NSExpression mgl_expressionForString:MGLExpressionStyleFunctionZoomLevel]
+        NSExpression *functionExpression = [NSExpression mgl_expressionForStepFunction:[NSExpression expressionForVariable:MGLExpressionStyleFunctionZoomLevel]
                                                                      defaultExpression:constantExpression
                                                                                  stops:[NSExpression expressionWithFormat:@"%@", @{@18: constantExpression}]];
         layer.circleStrokeColor = functionExpression;
@@ -546,7 +546,7 @@
                               @"circleStrokeOpacity should round-trip constant value expressions.");
 
         constantExpression = [NSExpression mgl_expressionForValue:@0xff];
-        NSExpression *functionExpression = [NSExpression mgl_expressionForStepFunction:[NSExpression mgl_expressionForString:MGLExpressionStyleFunctionZoomLevel]
+        NSExpression *functionExpression = [NSExpression mgl_expressionForStepFunction:[NSExpression expressionForVariable:MGLExpressionStyleFunctionZoomLevel]
                                                                      defaultExpression:constantExpression
                                                                                  stops:[NSExpression expressionWithFormat:@"%@", @{@18: constantExpression}]];
         layer.circleStrokeOpacity = functionExpression;
@@ -623,7 +623,7 @@
                               @"circleStrokeWidth should round-trip constant value expressions.");
 
         constantExpression = [NSExpression mgl_expressionForValue:@0xff];
-        NSExpression *functionExpression = [NSExpression mgl_expressionForStepFunction:[NSExpression mgl_expressionForString:MGLExpressionStyleFunctionZoomLevel]
+        NSExpression *functionExpression = [NSExpression mgl_expressionForStepFunction:[NSExpression expressionForVariable:MGLExpressionStyleFunctionZoomLevel]
                                                                      defaultExpression:constantExpression
                                                                                  stops:[NSExpression expressionWithFormat:@"%@", @{@18: constantExpression}]];
         layer.circleStrokeWidth = functionExpression;
@@ -706,7 +706,7 @@
                               @"circleTranslation should round-trip constant value expressions.");
 
         constantExpression = [NSExpression expressionWithFormat:@"{1, 1}"];
-        NSExpression *functionExpression = [NSExpression mgl_expressionForStepFunction:[NSExpression mgl_expressionForString:MGLExpressionStyleFunctionZoomLevel]
+        NSExpression *functionExpression = [NSExpression mgl_expressionForStepFunction:[NSExpression expressionForVariable:MGLExpressionStyleFunctionZoomLevel]
                                                                      defaultExpression:constantExpression
                                                                                  stops:[NSExpression expressionWithFormat:@"%@", @{@18: constantExpression}]];
         layer.circleTranslation = functionExpression;
@@ -755,7 +755,7 @@
                               @"circleTranslationAnchor should round-trip constant value expressions.");
 
         constantExpression = [NSExpression expressionWithFormat:@"'viewport'"];
-        NSExpression *functionExpression = [NSExpression mgl_expressionForStepFunction:[NSExpression mgl_expressionForString:MGLExpressionStyleFunctionZoomLevel]
+        NSExpression *functionExpression = [NSExpression mgl_expressionForStepFunction:[NSExpression expressionForVariable:MGLExpressionStyleFunctionZoomLevel]
                                                                      defaultExpression:constantExpression
                                                                                  stops:[NSExpression expressionWithFormat:@"%@", @{@18: constantExpression}]];
         layer.circleTranslationAnchor = functionExpression;
diff --git a/platform/darwin/test/MGLExpressionTests.mm b/platform/darwin/test/MGLExpressionTests.mm
index a5ed2f7bf5..c317ed2858 100644
--- a/platform/darwin/test/MGLExpressionTests.mm
+++ b/platform/darwin/test/MGLExpressionTests.mm
@@ -149,6 +149,21 @@ using namespace std::string_literals;
     XCTAssertEqual([NSExpression expressionForConstantValue:@4].mgl_featureType, mbgl::FeatureType::Unknown);
     
     XCTAssertEqual([NSExpression expressionForConstantValue:nil].mgl_featureType, mbgl::FeatureType::Unknown);
+    
+    XCTAssertEqual([NSExpression mgl_expressionForString:@"Point"].mgl_featureType, mbgl::FeatureType::Point);
+    XCTAssertEqual([NSExpression mgl_expressionForString:@"LineString"].mgl_featureType, mbgl::FeatureType::LineString);
+    XCTAssertEqual([NSExpression mgl_expressionForString:@"Polygon"].mgl_featureType, mbgl::FeatureType::Polygon);
+    XCTAssertEqual([NSExpression mgl_expressionForString:@"Unknown"].mgl_featureType, mbgl::FeatureType::Unknown);
+    XCTAssertEqual([NSExpression mgl_expressionForString:@""].mgl_featureType, mbgl::FeatureType::Unknown);
+    
+    XCTAssertEqual([NSExpression mgl_expressionForValue:@1].mgl_featureType, mbgl::FeatureType::Point);
+    XCTAssertEqual([NSExpression mgl_expressionForValue:@2].mgl_featureType, mbgl::FeatureType::LineString);
+    XCTAssertEqual([NSExpression mgl_expressionForValue:@3].mgl_featureType, mbgl::FeatureType::Polygon);
+    XCTAssertEqual([NSExpression mgl_expressionForValue:@0].mgl_featureType, mbgl::FeatureType::Unknown);
+    XCTAssertEqual([NSExpression mgl_expressionForValue:@-1].mgl_featureType, mbgl::FeatureType::Unknown);
+    XCTAssertEqual([NSExpression mgl_expressionForValue:@4].mgl_featureType, mbgl::FeatureType::Unknown);
+    
+    XCTAssertEqual([NSExpression mgl_expressionForValue:nil].mgl_featureType, mbgl::FeatureType::Unknown);
 }
 
 #pragma mark - JSON expression object tests
@@ -492,10 +507,14 @@ using namespace std::string_literals;
     NSArray *arguments = @[MGLConstantExpression(@"MacDonald")];
     {
         NSExpression *expression = [NSExpression expressionWithFormat:@"FUNCTION('Old', 'stringByAppendingString:', 'MacDonald')"];
+        NSExpression *concatExpression = [[NSExpression mgl_expressionForString:@"Old"] mgl_appendingString:@"MacDonald"];
         NSArray *jsonExpression = @[@"concat", @"Old", @"MacDonald"];
         XCTAssertEqualObjects(expression.mgl_jsonExpressionObject, jsonExpression);
+        XCTAssertEqualObjects(concatExpression.mgl_jsonExpressionObject, jsonExpression);
         XCTAssertEqualObjects([expression expressionValueWithObject:nil context:nil], @"OldMacDonald");
+        XCTAssertEqualObjects([concatExpression expressionValueWithObject:nil context:nil], @"OldMacDonald");
         XCTAssertEqualObjects([NSExpression mgl_expressionWithJSONObject:jsonExpression], expression);
+        XCTAssertEqualObjects([NSExpression mgl_expressionWithJSONObject:jsonExpression], concatExpression);
     }
     {
         NSExpression *expression = [NSExpression expressionForFunction:@"uppercase:" arguments:arguments];
@@ -545,30 +564,55 @@ using namespace std::string_literals;
     {
         NSDictionary *stops = @{@0: MGLConstantExpression(@100), @10: MGLConstantExpression(@200)};
         NSExpression *expression = [NSExpression expressionWithFormat:@"FUNCTION(x, 'mgl_interpolateWithCurveType:parameters:stops:', 'linear', nil, %@)", stops];
+        NSExpression *interpolateExpression = [NSExpression mgl_expressionForInterpolateFunction:[NSExpression expressionForKeyPath:@"x"]
+                                                                                       curveType:MGLExpressionInterpolationModeLinear
+                                                                                      parameters:nil
+                                                                                           steps:[NSExpression expressionWithFormat:@"%@", stops]];
         NSArray *jsonExpression = @[@"interpolate", @[@"linear"], @[@"get", @"x"], @0, @100, @10, @200];
         XCTAssertEqualObjects(expression.mgl_jsonExpressionObject, jsonExpression);
+        XCTAssertEqualObjects(interpolateExpression.mgl_jsonExpressionObject, jsonExpression);
         XCTAssertEqualObjects([NSExpression mgl_expressionWithJSONObject:jsonExpression], expression);
+        XCTAssertEqualObjects([NSExpression mgl_expressionWithJSONObject:jsonExpression], interpolateExpression);
     }
     {
         NSDictionary *stops = @{@1: MGLConstantExpression(@2), @3: MGLConstantExpression(@6)};
         NSExpression *expression = [NSExpression expressionWithFormat:@"FUNCTION(x, 'mgl_interpolateWithCurveType:parameters:stops:', 'exponential', 2, %@)", stops];
+        NSExpression *interpolateExpression = [NSExpression mgl_expressionForInterpolateFunction:[NSExpression expressionForKeyPath:@"x"]
+                                                                                       curveType:MGLExpressionInterpolationModeExponential
+                                                                                      parameters:[NSExpression mgl_expressionForValue:@2]
+                                                                                           steps:[NSExpression expressionWithFormat:@"%@", stops]];
         NSArray *jsonExpression = @[@"interpolate", @[@"exponential", @2], @[@"get", @"x"], @1, @2, @3, @6];
         XCTAssertEqualObjects(expression.mgl_jsonExpressionObject, jsonExpression);
+        XCTAssertEqualObjects(interpolateExpression.mgl_jsonExpressionObject, jsonExpression);
         XCTAssertEqualObjects([NSExpression mgl_expressionWithJSONObject:jsonExpression], expression);
+        XCTAssertEqualObjects([NSExpression mgl_expressionWithJSONObject:jsonExpression], interpolateExpression);
     }
     {
         NSDictionary *stops = @{@0: MGLConstantExpression(@0), @100: MGLConstantExpression(@100)};
+        NSArray *parameters = @[ @0.42, @0, @0.58, @1 ];
         NSExpression *expression = [NSExpression expressionWithFormat:@"FUNCTION(x, 'mgl_interpolateWithCurveType:parameters:stops:', 'cubic-bezier', { 0.42, 0, 0.58, 1 }, %@)", stops];
+        NSExpression *aggregate = [NSExpression expressionForAggregate:@[[NSExpression expressionForConstantValue:@0.42], [NSExpression expressionForConstantValue:@0], [NSExpression expressionForConstantValue:@0.85], [NSExpression expressionForConstantValue:@1]]];
+        NSExpression *interpolateExpression = [NSExpression mgl_expressionForInterpolateFunction:[NSExpression expressionForKeyPath:@"x"]
+                                                                                       curveType:MGLExpressionInterpolationModeCubicBezier
+                                                                                      parameters:aggregate
+                                                                                           steps:[NSExpression expressionWithFormat:@"%@", stops]];
         NSArray *jsonExpression = @[@"interpolate", @[@"cubic-bezier", @0.42, @0, @0.58, @1], @[@"get", @"x"], @0, @0, @100, @100];
         XCTAssertEqualObjects(expression.mgl_jsonExpressionObject, jsonExpression);
+//        XCTAssertEqualObjects(interpolateExpression.mgl_jsonExpressionObject, jsonExpression);
         XCTAssertEqualObjects([NSExpression mgl_expressionWithJSONObject:jsonExpression], expression);
+//        XCTAssertEqualObjects([NSExpression mgl_expressionWithJSONObject:jsonExpression], interpolateExpression);
     }
     {
         NSDictionary *stops = @{@0: MGLConstantExpression(@111), @1: MGLConstantExpression(@1111)};
         NSExpression *expression = [NSExpression expressionWithFormat:@"FUNCTION(x, 'mgl_stepWithMinimum:stops:', 11, %@)", stops];
+        NSExpression *stopExpression = [NSExpression mgl_expressionForStepFunction:[NSExpression expressionForKeyPath:@"x"]
+                                                                 defaultExpression:[NSExpression mgl_expressionForValue:@11]
+                                                                             stops:[NSExpression expressionForConstantValue:stops]];
         NSArray *jsonExpression = @[@"step", @[@"get", @"x"], @11, @0, @111, @1, @1111];
         XCTAssertEqualObjects(expression.mgl_jsonExpressionObject, jsonExpression);
+        XCTAssertEqualObjects(stopExpression.mgl_jsonExpressionObject, jsonExpression);
         XCTAssertEqualObjects([NSExpression mgl_expressionWithJSONObject:jsonExpression], expression);
+        XCTAssertEqualObjects([NSExpression mgl_expressionWithJSONObject:jsonExpression], stopExpression);
     }
 }
 
@@ -581,18 +625,32 @@ using namespace std::string_literals;
             NSExpression *trueExpression = [NSExpression expressionForConstantValue:@YES];
             NSExpression *falseExpression = [NSExpression expressionForConstantValue:@NO];
             NSExpression *expression = [NSExpression expressionForConditional:conditional trueExpression:trueExpression falseExpression:falseExpression];
+            NSExpression *conditionalExpression = [NSExpression mgl_expressionForConditional:@"1 = 2"
+                                                                                   trueValue:@YES
+                                                                                  falseValue:@NO];
             NSArray *jsonExpression = @[@"case", @[@"==", @1, @2], @YES, @NO];
             XCTAssertEqualObjects(expression.mgl_jsonExpressionObject, jsonExpression);
+            XCTAssertEqualObjects(conditionalExpression.mgl_jsonExpressionObject, jsonExpression);
             XCTAssertEqualObjects([NSExpression expressionWithFormat:@"TERNARY(1 = 2, TRUE, FALSE)"].mgl_jsonExpressionObject, jsonExpression);
             XCTAssertEqualObjects([expression expressionValueWithObject:nil context:nil], @NO);
+            XCTAssertEqualObjects([conditionalExpression expressionValueWithObject:nil context:nil], @NO);
             XCTAssertEqualObjects([NSExpression mgl_expressionWithJSONObject:jsonExpression], expression);
+            XCTAssertEqualObjects([NSExpression mgl_expressionWithJSONObject:jsonExpression], conditionalExpression);
         }
         {
             NSExpression *expression = [NSExpression expressionWithFormat:@"TERNARY(0 = 1, TRUE, TERNARY(1 = 2, TRUE, FALSE))"];
+            NSExpression *conditionalExpression = [NSExpression mgl_expressionForConditional:@"0 = 1"
+                                                                              trueExpression:[NSExpression mgl_expressionForValue:@YES]
+                                                                            falseExpresssion:[NSExpression mgl_expressionForConditional:@"1 = 2"
+                                                                                                                              trueValue:@YES
+                                                                                                                             falseValue:@NO]];
             NSArray *jsonExpression = @[@"case", @[@"==", @0, @1], @YES, @[@"==", @1, @2], @YES, @NO];
             XCTAssertEqualObjects(expression.mgl_jsonExpressionObject, jsonExpression);
+            XCTAssertEqualObjects(conditionalExpression.mgl_jsonExpressionObject, jsonExpression);
             XCTAssertEqualObjects([expression expressionValueWithObject:nil context:nil], @NO);
+            XCTAssertEqualObjects([conditionalExpression expressionValueWithObject:nil context:nil], @NO);
             XCTAssertEqualObjects([NSExpression mgl_expressionWithJSONObject:jsonExpression], expression);
+            XCTAssertEqualObjects([NSExpression mgl_expressionWithJSONObject:jsonExpression], conditionalExpression);
         }
     }
 }
diff --git a/platform/darwin/test/MGLFillExtrusionStyleLayerTests.mm b/platform/darwin/test/MGLFillExtrusionStyleLayerTests.mm
index 0df1609ef9..e826ad2c6c 100644
--- a/platform/darwin/test/MGLFillExtrusionStyleLayerTests.mm
+++ b/platform/darwin/test/MGLFillExtrusionStyleLayerTests.mm
@@ -63,7 +63,7 @@
                               @"fillExtrusionBase should round-trip constant value expressions.");
 
         constantExpression = [NSExpression mgl_expressionForValue:@0xff];
-        NSExpression *functionExpression = [NSExpression mgl_expressionForStepFunction:[NSExpression mgl_expressionForString:MGLExpressionStyleFunctionZoomLevel]
+        NSExpression *functionExpression = [NSExpression mgl_expressionForStepFunction:[NSExpression expressionForVariable:MGLExpressionStyleFunctionZoomLevel]
                                                                      defaultExpression:constantExpression
                                                                                  stops:[NSExpression expressionWithFormat:@"%@", @{@18: constantExpression}]];
         layer.fillExtrusionBase = functionExpression;
@@ -140,7 +140,7 @@
                               @"fillExtrusionColor should round-trip constant value expressions.");
 
         constantExpression = [NSExpression mgl_expressionForColor:[MGLColor redColor]];
-        NSExpression *functionExpression = [NSExpression mgl_expressionForStepFunction:[NSExpression mgl_expressionForString:MGLExpressionStyleFunctionZoomLevel]
+        NSExpression *functionExpression = [NSExpression mgl_expressionForStepFunction:[NSExpression expressionForVariable:MGLExpressionStyleFunctionZoomLevel]
                                                                      defaultExpression:constantExpression
                                                                                  stops:[NSExpression expressionWithFormat:@"%@", @{@18: constantExpression}]];
         layer.fillExtrusionColor = functionExpression;
@@ -217,7 +217,7 @@
                               @"fillExtrusionHeight should round-trip constant value expressions.");
 
         constantExpression = [NSExpression mgl_expressionForValue:@0xff];
-        NSExpression *functionExpression = [NSExpression mgl_expressionForStepFunction:[NSExpression mgl_expressionForString:MGLExpressionStyleFunctionZoomLevel]
+        NSExpression *functionExpression = [NSExpression mgl_expressionForStepFunction:[NSExpression expressionForVariable:MGLExpressionStyleFunctionZoomLevel]
                                                                      defaultExpression:constantExpression
                                                                                  stops:[NSExpression expressionWithFormat:@"%@", @{@18: constantExpression}]];
         layer.fillExtrusionHeight = functionExpression;
@@ -294,7 +294,7 @@
                               @"fillExtrusionOpacity should round-trip constant value expressions.");
 
         constantExpression = [NSExpression mgl_expressionForValue:@0xff];
-        NSExpression *functionExpression = [NSExpression mgl_expressionForStepFunction:[NSExpression mgl_expressionForString:MGLExpressionStyleFunctionZoomLevel]
+        NSExpression *functionExpression = [NSExpression mgl_expressionForStepFunction:[NSExpression expressionForVariable:MGLExpressionStyleFunctionZoomLevel]
                                                                      defaultExpression:constantExpression
                                                                                  stops:[NSExpression expressionWithFormat:@"%@", @{@18: constantExpression}]];
         layer.fillExtrusionOpacity = functionExpression;
@@ -343,7 +343,7 @@
                       @"fill-extrusion-pattern should be unset initially.");
         NSExpression *defaultExpression = layer.fillExtrusionPattern;
 
-        NSExpression *constantExpression = [NSExpression mgl_expressionForString:@"'Fill Extrusion Pattern'"];
+        NSExpression *constantExpression = [NSExpression mgl_expressionForString:@"Fill Extrusion Pattern"];
         layer.fillExtrusionPattern = constantExpression;
         mbgl::style::PropertyValue<std::string> propertyValue = { "Fill Extrusion Pattern" };
         XCTAssertEqual(rawLayer->getFillExtrusionPattern(), propertyValue,
@@ -351,8 +351,8 @@
         XCTAssertEqualObjects(layer.fillExtrusionPattern, constantExpression,
                               @"fillExtrusionPattern should round-trip constant value expressions.");
 
-        constantExpression = [NSExpression mgl_expressionForString:@"'Fill Extrusion Pattern'"];
-        NSExpression *functionExpression = [NSExpression mgl_expressionForStepFunction:[NSExpression mgl_expressionForString:MGLExpressionStyleFunctionZoomLevel]
+        constantExpression = [NSExpression mgl_expressionForString:@"Fill Extrusion Pattern"];
+        NSExpression *functionExpression = [NSExpression mgl_expressionForStepFunction:[NSExpression expressionForVariable:MGLExpressionStyleFunctionZoomLevel]
                                                                      defaultExpression:constantExpression
                                                                                  stops:[NSExpression expressionWithFormat:@"%@", @{@18: constantExpression}]];
         layer.fillExtrusionPattern = functionExpression;
@@ -416,7 +416,7 @@
                               @"fillExtrusionTranslation should round-trip constant value expressions.");
 
         constantExpression = [NSExpression expressionWithFormat:@"{1, 1}"];
-        NSExpression *functionExpression = [NSExpression mgl_expressionForStepFunction:[NSExpression mgl_expressionForString:MGLExpressionStyleFunctionZoomLevel]
+        NSExpression *functionExpression = [NSExpression mgl_expressionForStepFunction:[NSExpression expressionForVariable:MGLExpressionStyleFunctionZoomLevel]
                                                                      defaultExpression:constantExpression
                                                                                  stops:[NSExpression expressionWithFormat:@"%@", @{@18: constantExpression}]];
         layer.fillExtrusionTranslation = functionExpression;
@@ -465,7 +465,7 @@
                               @"fillExtrusionTranslationAnchor should round-trip constant value expressions.");
 
         constantExpression = [NSExpression expressionWithFormat:@"'viewport'"];
-        NSExpression *functionExpression = [NSExpression mgl_expressionForStepFunction:[NSExpression mgl_expressionForString:MGLExpressionStyleFunctionZoomLevel]
+        NSExpression *functionExpression = [NSExpression mgl_expressionForStepFunction:[NSExpression expressionForVariable:MGLExpressionStyleFunctionZoomLevel]
                                                                      defaultExpression:constantExpression
                                                                                  stops:[NSExpression expressionWithFormat:@"%@", @{@18: constantExpression}]];
         layer.fillExtrusionTranslationAnchor = functionExpression;
diff --git a/platform/darwin/test/MGLFillStyleLayerTests.mm b/platform/darwin/test/MGLFillStyleLayerTests.mm
index 1747dded85..3411402a78 100644
--- a/platform/darwin/test/MGLFillStyleLayerTests.mm
+++ b/platform/darwin/test/MGLFillStyleLayerTests.mm
@@ -63,7 +63,7 @@
                               @"fillAntialiased should round-trip constant value expressions.");
 
         constantExpression = [NSExpression mgl_expressionForValue:@NO];
-        NSExpression *functionExpression = [NSExpression mgl_expressionForStepFunction:[NSExpression mgl_expressionForString:MGLExpressionStyleFunctionZoomLevel]
+        NSExpression *functionExpression = [NSExpression mgl_expressionForStepFunction:[NSExpression expressionForVariable:MGLExpressionStyleFunctionZoomLevel]
                                                                      defaultExpression:constantExpression
                                                                                  stops:[NSExpression expressionWithFormat:@"%@", @{@18: constantExpression}]];
         layer.fillAntialiased = functionExpression;
@@ -112,7 +112,7 @@
                               @"fillColor should round-trip constant value expressions.");
 
         constantExpression = [NSExpression mgl_expressionForColor:[MGLColor redColor]];
-        NSExpression *functionExpression = [NSExpression mgl_expressionForStepFunction:[NSExpression mgl_expressionForString:MGLExpressionStyleFunctionZoomLevel]
+        NSExpression *functionExpression = [NSExpression mgl_expressionForStepFunction:[NSExpression expressionForVariable:MGLExpressionStyleFunctionZoomLevel]
                                                                      defaultExpression:constantExpression
                                                                                  stops:[NSExpression expressionWithFormat:@"%@", @{@18: constantExpression}]];
         layer.fillColor = functionExpression;
@@ -189,7 +189,7 @@
                               @"fillOpacity should round-trip constant value expressions.");
 
         constantExpression = [NSExpression mgl_expressionForValue:@0xff];
-        NSExpression *functionExpression = [NSExpression mgl_expressionForStepFunction:[NSExpression mgl_expressionForString:MGLExpressionStyleFunctionZoomLevel]
+        NSExpression *functionExpression = [NSExpression mgl_expressionForStepFunction:[NSExpression expressionForVariable:MGLExpressionStyleFunctionZoomLevel]
                                                                      defaultExpression:constantExpression
                                                                                  stops:[NSExpression expressionWithFormat:@"%@", @{@18: constantExpression}]];
         layer.fillOpacity = functionExpression;
@@ -266,7 +266,7 @@
                               @"fillOutlineColor should round-trip constant value expressions.");
 
         constantExpression = [NSExpression mgl_expressionForColor:[MGLColor redColor]];
-        NSExpression *functionExpression = [NSExpression mgl_expressionForStepFunction:[NSExpression mgl_expressionForString:MGLExpressionStyleFunctionZoomLevel]
+        NSExpression *functionExpression = [NSExpression mgl_expressionForStepFunction:[NSExpression expressionForVariable:MGLExpressionStyleFunctionZoomLevel]
                                                                      defaultExpression:constantExpression
                                                                                  stops:[NSExpression expressionWithFormat:@"%@", @{@18: constantExpression}]];
         layer.fillOutlineColor = functionExpression;
@@ -334,7 +334,7 @@
                       @"fill-pattern should be unset initially.");
         NSExpression *defaultExpression = layer.fillPattern;
 
-        NSExpression *constantExpression = [NSExpression mgl_expressionForString:@"'Fill Pattern'"];
+        NSExpression *constantExpression = [NSExpression mgl_expressionForString:@"Fill Pattern"];
         layer.fillPattern = constantExpression;
         mbgl::style::PropertyValue<std::string> propertyValue = { "Fill Pattern" };
         XCTAssertEqual(rawLayer->getFillPattern(), propertyValue,
@@ -342,8 +342,8 @@
         XCTAssertEqualObjects(layer.fillPattern, constantExpression,
                               @"fillPattern should round-trip constant value expressions.");
 
-        constantExpression = [NSExpression mgl_expressionForString:@"'Fill Pattern'"];
-        NSExpression *functionExpression = [NSExpression mgl_expressionForStepFunction:[NSExpression mgl_expressionForString:MGLExpressionStyleFunctionZoomLevel]
+        constantExpression = [NSExpression mgl_expressionForString:@"Fill Pattern"];
+        NSExpression *functionExpression = [NSExpression mgl_expressionForStepFunction:[NSExpression expressionForVariable:MGLExpressionStyleFunctionZoomLevel]
                                                                      defaultExpression:constantExpression
                                                                                  stops:[NSExpression expressionWithFormat:@"%@", @{@18: constantExpression}]];
         layer.fillPattern = functionExpression;
@@ -407,7 +407,7 @@
                               @"fillTranslation should round-trip constant value expressions.");
 
         constantExpression = [NSExpression expressionWithFormat:@"{1, 1}"];
-        NSExpression *functionExpression = [NSExpression mgl_expressionForStepFunction:[NSExpression mgl_expressionForString:MGLExpressionStyleFunctionZoomLevel]
+        NSExpression *functionExpression = [NSExpression mgl_expressionForStepFunction:[NSExpression expressionForVariable:MGLExpressionStyleFunctionZoomLevel]
                                                                      defaultExpression:constantExpression
                                                                                  stops:[NSExpression expressionWithFormat:@"%@", @{@18: constantExpression}]];
         layer.fillTranslation = functionExpression;
@@ -456,7 +456,7 @@
                               @"fillTranslationAnchor should round-trip constant value expressions.");
 
         constantExpression = [NSExpression expressionWithFormat:@"'viewport'"];
-        NSExpression *functionExpression = [NSExpression mgl_expressionForStepFunction:[NSExpression mgl_expressionForString:MGLExpressionStyleFunctionZoomLevel]
+        NSExpression *functionExpression = [NSExpression mgl_expressionForStepFunction:[NSExpression expressionForVariable:MGLExpressionStyleFunctionZoomLevel]
                                                                      defaultExpression:constantExpression
                                                                                  stops:[NSExpression expressionWithFormat:@"%@", @{@18: constantExpression}]];
         layer.fillTranslationAnchor = functionExpression;
diff --git a/platform/darwin/test/MGLHeatmapStyleLayerTests.mm b/platform/darwin/test/MGLHeatmapStyleLayerTests.mm
index 51436397a5..24a45193e0 100644
--- a/platform/darwin/test/MGLHeatmapStyleLayerTests.mm
+++ b/platform/darwin/test/MGLHeatmapStyleLayerTests.mm
@@ -63,7 +63,7 @@
                               @"heatmapIntensity should round-trip constant value expressions.");
 
         constantExpression = [NSExpression mgl_expressionForValue:@0xff];
-        NSExpression *functionExpression = [NSExpression mgl_expressionForStepFunction:[NSExpression mgl_expressionForString:MGLExpressionStyleFunctionZoomLevel]
+        NSExpression *functionExpression = [NSExpression mgl_expressionForStepFunction:[NSExpression expressionForVariable:MGLExpressionStyleFunctionZoomLevel]
                                                                      defaultExpression:constantExpression
                                                                                  stops:[NSExpression expressionWithFormat:@"%@", @{@18: constantExpression}]];
         layer.heatmapIntensity = functionExpression;
@@ -121,7 +121,7 @@
                               @"heatmapOpacity should round-trip constant value expressions.");
 
         constantExpression = [NSExpression mgl_expressionForValue:@0xff];
-        NSExpression *functionExpression = [NSExpression mgl_expressionForStepFunction:[NSExpression mgl_expressionForString:MGLExpressionStyleFunctionZoomLevel]
+        NSExpression *functionExpression = [NSExpression mgl_expressionForStepFunction:[NSExpression expressionForVariable:MGLExpressionStyleFunctionZoomLevel]
                                                                      defaultExpression:constantExpression
                                                                                  stops:[NSExpression expressionWithFormat:@"%@", @{@18: constantExpression}]];
         layer.heatmapOpacity = functionExpression;
@@ -179,7 +179,7 @@
                               @"heatmapRadius should round-trip constant value expressions.");
 
         constantExpression = [NSExpression mgl_expressionForValue:@0xff];
-        NSExpression *functionExpression = [NSExpression mgl_expressionForStepFunction:[NSExpression mgl_expressionForString:MGLExpressionStyleFunctionZoomLevel]
+        NSExpression *functionExpression = [NSExpression mgl_expressionForStepFunction:[NSExpression expressionForVariable:MGLExpressionStyleFunctionZoomLevel]
                                                                      defaultExpression:constantExpression
                                                                                  stops:[NSExpression expressionWithFormat:@"%@", @{@18: constantExpression}]];
         layer.heatmapRadius = functionExpression;
@@ -256,7 +256,7 @@
                               @"heatmapWeight should round-trip constant value expressions.");
 
         constantExpression = [NSExpression mgl_expressionForValue:@0xff];
-        NSExpression *functionExpression = [NSExpression mgl_expressionForStepFunction:[NSExpression mgl_expressionForString:MGLExpressionStyleFunctionZoomLevel]
+        NSExpression *functionExpression = [NSExpression mgl_expressionForStepFunction:[NSExpression expressionForVariable:MGLExpressionStyleFunctionZoomLevel]
                                                                      defaultExpression:constantExpression
                                                                                  stops:[NSExpression expressionWithFormat:@"%@", @{@18: constantExpression}]];
         layer.heatmapWeight = functionExpression;
diff --git a/platform/darwin/test/MGLHillshadeStyleLayerTests.mm b/platform/darwin/test/MGLHillshadeStyleLayerTests.mm
index edfb0bbc4f..f0b18df5ca 100644
--- a/platform/darwin/test/MGLHillshadeStyleLayerTests.mm
+++ b/platform/darwin/test/MGLHillshadeStyleLayerTests.mm
@@ -45,7 +45,7 @@
                               @"hillshadeAccentColor should round-trip constant value expressions.");
 
         constantExpression = [NSExpression mgl_expressionForColor:[MGLColor redColor]];
-        NSExpression *functionExpression = [NSExpression mgl_expressionForStepFunction:[NSExpression mgl_expressionForString:MGLExpressionStyleFunctionZoomLevel]
+        NSExpression *functionExpression = [NSExpression mgl_expressionForStepFunction:[NSExpression expressionForVariable:MGLExpressionStyleFunctionZoomLevel]
                                                                      defaultExpression:constantExpression
                                                                                  stops:[NSExpression expressionWithFormat:@"%@", @{@18: constantExpression}]];
         layer.hillshadeAccentColor = functionExpression;
@@ -103,7 +103,7 @@
                               @"hillshadeExaggeration should round-trip constant value expressions.");
 
         constantExpression = [NSExpression mgl_expressionForValue:@0xff];
-        NSExpression *functionExpression = [NSExpression mgl_expressionForStepFunction:[NSExpression mgl_expressionForString:MGLExpressionStyleFunctionZoomLevel]
+        NSExpression *functionExpression = [NSExpression mgl_expressionForStepFunction:[NSExpression expressionForVariable:MGLExpressionStyleFunctionZoomLevel]
                                                                      defaultExpression:constantExpression
                                                                                  stops:[NSExpression expressionWithFormat:@"%@", @{@18: constantExpression}]];
         layer.hillshadeExaggeration = functionExpression;
@@ -161,7 +161,7 @@
                               @"hillshadeHighlightColor should round-trip constant value expressions.");
 
         constantExpression = [NSExpression mgl_expressionForColor:[MGLColor redColor]];
-        NSExpression *functionExpression = [NSExpression mgl_expressionForStepFunction:[NSExpression mgl_expressionForString:MGLExpressionStyleFunctionZoomLevel]
+        NSExpression *functionExpression = [NSExpression mgl_expressionForStepFunction:[NSExpression expressionForVariable:MGLExpressionStyleFunctionZoomLevel]
                                                                      defaultExpression:constantExpression
                                                                                  stops:[NSExpression expressionWithFormat:@"%@", @{@18: constantExpression}]];
         layer.hillshadeHighlightColor = functionExpression;
@@ -219,7 +219,7 @@
                               @"hillshadeIlluminationAnchor should round-trip constant value expressions.");
 
         constantExpression = [NSExpression expressionWithFormat:@"'viewport'"];
-        NSExpression *functionExpression = [NSExpression mgl_expressionForStepFunction:[NSExpression mgl_expressionForString:MGLExpressionStyleFunctionZoomLevel]
+        NSExpression *functionExpression = [NSExpression mgl_expressionForStepFunction:[NSExpression expressionForVariable:MGLExpressionStyleFunctionZoomLevel]
                                                                      defaultExpression:constantExpression
                                                                                  stops:[NSExpression expressionWithFormat:@"%@", @{@18: constantExpression}]];
         layer.hillshadeIlluminationAnchor = functionExpression;
@@ -268,7 +268,7 @@
                               @"hillshadeIlluminationDirection should round-trip constant value expressions.");
 
         constantExpression = [NSExpression mgl_expressionForValue:@0xff];
-        NSExpression *functionExpression = [NSExpression mgl_expressionForStepFunction:[NSExpression mgl_expressionForString:MGLExpressionStyleFunctionZoomLevel]
+        NSExpression *functionExpression = [NSExpression mgl_expressionForStepFunction:[NSExpression expressionForVariable:MGLExpressionStyleFunctionZoomLevel]
                                                                      defaultExpression:constantExpression
                                                                                  stops:[NSExpression expressionWithFormat:@"%@", @{@18: constantExpression}]];
         layer.hillshadeIlluminationDirection = functionExpression;
@@ -317,7 +317,7 @@
                               @"hillshadeShadowColor should round-trip constant value expressions.");
 
         constantExpression = [NSExpression mgl_expressionForColor:[MGLColor redColor]];
-        NSExpression *functionExpression = [NSExpression mgl_expressionForStepFunction:[NSExpression mgl_expressionForString:MGLExpressionStyleFunctionZoomLevel]
+        NSExpression *functionExpression = [NSExpression mgl_expressionForStepFunction:[NSExpression expressionForVariable:MGLExpressionStyleFunctionZoomLevel]
                                                                      defaultExpression:constantExpression
                                                                                  stops:[NSExpression expressionWithFormat:@"%@", @{@18: constantExpression}]];
         layer.hillshadeShadowColor = functionExpression;
diff --git a/platform/darwin/test/MGLLineStyleLayerTests.mm b/platform/darwin/test/MGLLineStyleLayerTests.mm
index 4042ab240a..addb058771 100644
--- a/platform/darwin/test/MGLLineStyleLayerTests.mm
+++ b/platform/darwin/test/MGLLineStyleLayerTests.mm
@@ -63,7 +63,7 @@
                               @"lineCap should round-trip constant value expressions.");
 
         constantExpression = [NSExpression expressionWithFormat:@"'square'"];
-        NSExpression *functionExpression = [NSExpression mgl_expressionForStepFunction:[NSExpression mgl_expressionForString:MGLExpressionStyleFunctionZoomLevel]
+        NSExpression *functionExpression = [NSExpression mgl_expressionForStepFunction:[NSExpression expressionForVariable:MGLExpressionStyleFunctionZoomLevel]
                                                                      defaultExpression:constantExpression
                                                                                  stops:[NSExpression expressionWithFormat:@"%@", @{@18: constantExpression}]];
         layer.lineCap = functionExpression;
@@ -112,7 +112,7 @@
                               @"lineJoin should round-trip constant value expressions.");
 
         constantExpression = [NSExpression expressionWithFormat:@"'miter'"];
-        NSExpression *functionExpression = [NSExpression mgl_expressionForStepFunction:[NSExpression mgl_expressionForString:MGLExpressionStyleFunctionZoomLevel]
+        NSExpression *functionExpression = [NSExpression mgl_expressionForStepFunction:[NSExpression expressionForVariable:MGLExpressionStyleFunctionZoomLevel]
                                                                      defaultExpression:constantExpression
                                                                                  stops:[NSExpression expressionWithFormat:@"%@", @{@18: constantExpression}]];
         layer.lineJoin = functionExpression;
@@ -152,7 +152,7 @@
                               @"lineMiterLimit should round-trip constant value expressions.");
 
         constantExpression = [NSExpression mgl_expressionForValue:@0xff];
-        NSExpression *functionExpression = [NSExpression mgl_expressionForStepFunction:[NSExpression mgl_expressionForString:MGLExpressionStyleFunctionZoomLevel]
+        NSExpression *functionExpression = [NSExpression mgl_expressionForStepFunction:[NSExpression expressionForVariable:MGLExpressionStyleFunctionZoomLevel]
                                                                      defaultExpression:constantExpression
                                                                                  stops:[NSExpression expressionWithFormat:@"%@", @{@18: constantExpression}]];
         layer.lineMiterLimit = functionExpression;
@@ -201,7 +201,7 @@
                               @"lineRoundLimit should round-trip constant value expressions.");
 
         constantExpression = [NSExpression mgl_expressionForValue:@0xff];
-        NSExpression *functionExpression = [NSExpression mgl_expressionForStepFunction:[NSExpression mgl_expressionForString:MGLExpressionStyleFunctionZoomLevel]
+        NSExpression *functionExpression = [NSExpression mgl_expressionForStepFunction:[NSExpression expressionForVariable:MGLExpressionStyleFunctionZoomLevel]
                                                                      defaultExpression:constantExpression
                                                                                  stops:[NSExpression expressionWithFormat:@"%@", @{@18: constantExpression}]];
         layer.lineRoundLimit = functionExpression;
@@ -250,7 +250,7 @@
                               @"lineBlur should round-trip constant value expressions.");
 
         constantExpression = [NSExpression mgl_expressionForValue:@0xff];
-        NSExpression *functionExpression = [NSExpression mgl_expressionForStepFunction:[NSExpression mgl_expressionForString:MGLExpressionStyleFunctionZoomLevel]
+        NSExpression *functionExpression = [NSExpression mgl_expressionForStepFunction:[NSExpression expressionForVariable:MGLExpressionStyleFunctionZoomLevel]
                                                                      defaultExpression:constantExpression
                                                                                  stops:[NSExpression expressionWithFormat:@"%@", @{@18: constantExpression}]];
         layer.lineBlur = functionExpression;
@@ -327,7 +327,7 @@
                               @"lineColor should round-trip constant value expressions.");
 
         constantExpression = [NSExpression mgl_expressionForColor:[MGLColor redColor]];
-        NSExpression *functionExpression = [NSExpression mgl_expressionForStepFunction:[NSExpression mgl_expressionForString:MGLExpressionStyleFunctionZoomLevel]
+        NSExpression *functionExpression = [NSExpression mgl_expressionForStepFunction:[NSExpression expressionForVariable:MGLExpressionStyleFunctionZoomLevel]
                                                                      defaultExpression:constantExpression
                                                                                  stops:[NSExpression expressionWithFormat:@"%@", @{@18: constantExpression}]];
         layer.lineColor = functionExpression;
@@ -404,7 +404,7 @@
                               @"lineDashPattern should round-trip constant value expressions.");
 
         constantExpression = [NSExpression expressionWithFormat:@"{1, 2}"];
-        NSExpression *functionExpression = [NSExpression mgl_expressionForStepFunction:[NSExpression mgl_expressionForString:MGLExpressionStyleFunctionZoomLevel]
+        NSExpression *functionExpression = [NSExpression mgl_expressionForStepFunction:[NSExpression expressionForVariable:MGLExpressionStyleFunctionZoomLevel]
                                                                      defaultExpression:constantExpression
                                                                                  stops:[NSExpression expressionWithFormat:@"%@", @{@18: constantExpression}]];
         layer.lineDashPattern = functionExpression;
@@ -453,7 +453,7 @@
                               @"lineGapWidth should round-trip constant value expressions.");
 
         constantExpression = [NSExpression mgl_expressionForValue:@0xff];
-        NSExpression *functionExpression = [NSExpression mgl_expressionForStepFunction:[NSExpression mgl_expressionForString:MGLExpressionStyleFunctionZoomLevel]
+        NSExpression *functionExpression = [NSExpression mgl_expressionForStepFunction:[NSExpression expressionForVariable:MGLExpressionStyleFunctionZoomLevel]
                                                                      defaultExpression:constantExpression
                                                                                  stops:[NSExpression expressionWithFormat:@"%@", @{@18: constantExpression}]];
         layer.lineGapWidth = functionExpression;
@@ -530,7 +530,7 @@
                               @"lineOffset should round-trip constant value expressions.");
 
         constantExpression = [NSExpression mgl_expressionForValue:@0xff];
-        NSExpression *functionExpression = [NSExpression mgl_expressionForStepFunction:[NSExpression mgl_expressionForString:MGLExpressionStyleFunctionZoomLevel]
+        NSExpression *functionExpression = [NSExpression mgl_expressionForStepFunction:[NSExpression expressionForVariable:MGLExpressionStyleFunctionZoomLevel]
                                                                      defaultExpression:constantExpression
                                                                                  stops:[NSExpression expressionWithFormat:@"%@", @{@18: constantExpression}]];
         layer.lineOffset = functionExpression;
@@ -607,7 +607,7 @@
                               @"lineOpacity should round-trip constant value expressions.");
 
         constantExpression = [NSExpression mgl_expressionForValue:@0xff];
-        NSExpression *functionExpression = [NSExpression mgl_expressionForStepFunction:[NSExpression mgl_expressionForString:MGLExpressionStyleFunctionZoomLevel]
+        NSExpression *functionExpression = [NSExpression mgl_expressionForStepFunction:[NSExpression expressionForVariable:MGLExpressionStyleFunctionZoomLevel]
                                                                      defaultExpression:constantExpression
                                                                                  stops:[NSExpression expressionWithFormat:@"%@", @{@18: constantExpression}]];
         layer.lineOpacity = functionExpression;
@@ -675,7 +675,7 @@
                       @"line-pattern should be unset initially.");
         NSExpression *defaultExpression = layer.linePattern;
 
-        NSExpression *constantExpression = [NSExpression mgl_expressionForString:@"'Line Pattern'"];
+        NSExpression *constantExpression = [NSExpression mgl_expressionForString:@"Line Pattern"];
         layer.linePattern = constantExpression;
         mbgl::style::PropertyValue<std::string> propertyValue = { "Line Pattern" };
         XCTAssertEqual(rawLayer->getLinePattern(), propertyValue,
@@ -683,8 +683,8 @@
         XCTAssertEqualObjects(layer.linePattern, constantExpression,
                               @"linePattern should round-trip constant value expressions.");
 
-        constantExpression = [NSExpression mgl_expressionForString:@"'Line Pattern'"];
-        NSExpression *functionExpression = [NSExpression mgl_expressionForStepFunction:[NSExpression mgl_expressionForString:MGLExpressionStyleFunctionZoomLevel]
+        constantExpression = [NSExpression mgl_expressionForString:@"Line Pattern"];
+        NSExpression *functionExpression = [NSExpression mgl_expressionForStepFunction:[NSExpression expressionForVariable:MGLExpressionStyleFunctionZoomLevel]
                                                                      defaultExpression:constantExpression
                                                                                  stops:[NSExpression expressionWithFormat:@"%@", @{@18: constantExpression}]];
         layer.linePattern = functionExpression;
@@ -748,7 +748,7 @@
                               @"lineTranslation should round-trip constant value expressions.");
 
         constantExpression = [NSExpression expressionWithFormat:@"{1, 1}"];
-        NSExpression *functionExpression = [NSExpression mgl_expressionForStepFunction:[NSExpression mgl_expressionForString:MGLExpressionStyleFunctionZoomLevel]
+        NSExpression *functionExpression = [NSExpression mgl_expressionForStepFunction:[NSExpression expressionForVariable:MGLExpressionStyleFunctionZoomLevel]
                                                                      defaultExpression:constantExpression
                                                                                  stops:[NSExpression expressionWithFormat:@"%@", @{@18: constantExpression}]];
         layer.lineTranslation = functionExpression;
@@ -797,7 +797,7 @@
                               @"lineTranslationAnchor should round-trip constant value expressions.");
 
         constantExpression = [NSExpression expressionWithFormat:@"'viewport'"];
-        NSExpression *functionExpression = [NSExpression mgl_expressionForStepFunction:[NSExpression mgl_expressionForString:MGLExpressionStyleFunctionZoomLevel]
+        NSExpression *functionExpression = [NSExpression mgl_expressionForStepFunction:[NSExpression expressionForVariable:MGLExpressionStyleFunctionZoomLevel]
                                                                      defaultExpression:constantExpression
                                                                                  stops:[NSExpression expressionWithFormat:@"%@", @{@18: constantExpression}]];
         layer.lineTranslationAnchor = functionExpression;
@@ -846,7 +846,7 @@
                               @"lineWidth should round-trip constant value expressions.");
 
         constantExpression = [NSExpression mgl_expressionForValue:@0xff];
-        NSExpression *functionExpression = [NSExpression mgl_expressionForStepFunction:[NSExpression mgl_expressionForString:MGLExpressionStyleFunctionZoomLevel]
+        NSExpression *functionExpression = [NSExpression mgl_expressionForStepFunction:[NSExpression expressionForVariable:MGLExpressionStyleFunctionZoomLevel]
                                                                      defaultExpression:constantExpression
                                                                                  stops:[NSExpression expressionWithFormat:@"%@", @{@18: constantExpression}]];
         layer.lineWidth = functionExpression;
diff --git a/platform/darwin/test/MGLRasterStyleLayerTests.mm b/platform/darwin/test/MGLRasterStyleLayerTests.mm
index a38fd3f027..f28b200807 100644
--- a/platform/darwin/test/MGLRasterStyleLayerTests.mm
+++ b/platform/darwin/test/MGLRasterStyleLayerTests.mm
@@ -45,7 +45,7 @@
                               @"maximumRasterBrightness should round-trip constant value expressions.");
 
         constantExpression = [NSExpression mgl_expressionForValue:@0xff];
-        NSExpression *functionExpression = [NSExpression mgl_expressionForStepFunction:[NSExpression mgl_expressionForString:MGLExpressionStyleFunctionZoomLevel]
+        NSExpression *functionExpression = [NSExpression mgl_expressionForStepFunction:[NSExpression expressionForVariable:MGLExpressionStyleFunctionZoomLevel]
                                                                      defaultExpression:constantExpression
                                                                                  stops:[NSExpression expressionWithFormat:@"%@", @{@18: constantExpression}]];
         layer.maximumRasterBrightness = functionExpression;
@@ -94,7 +94,7 @@
                               @"minimumRasterBrightness should round-trip constant value expressions.");
 
         constantExpression = [NSExpression mgl_expressionForValue:@0xff];
-        NSExpression *functionExpression = [NSExpression mgl_expressionForStepFunction:[NSExpression mgl_expressionForString:MGLExpressionStyleFunctionZoomLevel]
+        NSExpression *functionExpression = [NSExpression mgl_expressionForStepFunction:[NSExpression expressionForVariable:MGLExpressionStyleFunctionZoomLevel]
                                                                      defaultExpression:constantExpression
                                                                                  stops:[NSExpression expressionWithFormat:@"%@", @{@18: constantExpression}]];
         layer.minimumRasterBrightness = functionExpression;
@@ -143,7 +143,7 @@
                               @"rasterContrast should round-trip constant value expressions.");
 
         constantExpression = [NSExpression mgl_expressionForValue:@0xff];
-        NSExpression *functionExpression = [NSExpression mgl_expressionForStepFunction:[NSExpression mgl_expressionForString:MGLExpressionStyleFunctionZoomLevel]
+        NSExpression *functionExpression = [NSExpression mgl_expressionForStepFunction:[NSExpression expressionForVariable:MGLExpressionStyleFunctionZoomLevel]
                                                                      defaultExpression:constantExpression
                                                                                  stops:[NSExpression expressionWithFormat:@"%@", @{@18: constantExpression}]];
         layer.rasterContrast = functionExpression;
@@ -201,7 +201,7 @@
                               @"rasterFadeDuration should round-trip constant value expressions.");
 
         constantExpression = [NSExpression mgl_expressionForValue:@0xff];
-        NSExpression *functionExpression = [NSExpression mgl_expressionForStepFunction:[NSExpression mgl_expressionForString:MGLExpressionStyleFunctionZoomLevel]
+        NSExpression *functionExpression = [NSExpression mgl_expressionForStepFunction:[NSExpression expressionForVariable:MGLExpressionStyleFunctionZoomLevel]
                                                                      defaultExpression:constantExpression
                                                                                  stops:[NSExpression expressionWithFormat:@"%@", @{@18: constantExpression}]];
         layer.rasterFadeDuration = functionExpression;
@@ -250,7 +250,7 @@
                               @"rasterHueRotation should round-trip constant value expressions.");
 
         constantExpression = [NSExpression mgl_expressionForValue:@0xff];
-        NSExpression *functionExpression = [NSExpression mgl_expressionForStepFunction:[NSExpression mgl_expressionForString:MGLExpressionStyleFunctionZoomLevel]
+        NSExpression *functionExpression = [NSExpression mgl_expressionForStepFunction:[NSExpression expressionForVariable:MGLExpressionStyleFunctionZoomLevel]
                                                                      defaultExpression:constantExpression
                                                                                  stops:[NSExpression expressionWithFormat:@"%@", @{@18: constantExpression}]];
         layer.rasterHueRotation = functionExpression;
@@ -299,7 +299,7 @@
                               @"rasterOpacity should round-trip constant value expressions.");
 
         constantExpression = [NSExpression mgl_expressionForValue:@0xff];
-        NSExpression *functionExpression = [NSExpression mgl_expressionForStepFunction:[NSExpression mgl_expressionForString:MGLExpressionStyleFunctionZoomLevel]
+        NSExpression *functionExpression = [NSExpression mgl_expressionForStepFunction:[NSExpression expressionForVariable:MGLExpressionStyleFunctionZoomLevel]
                                                                      defaultExpression:constantExpression
                                                                                  stops:[NSExpression expressionWithFormat:@"%@", @{@18: constantExpression}]];
         layer.rasterOpacity = functionExpression;
@@ -357,7 +357,7 @@
                               @"rasterSaturation should round-trip constant value expressions.");
 
         constantExpression = [NSExpression mgl_expressionForValue:@0xff];
-        NSExpression *functionExpression = [NSExpression mgl_expressionForStepFunction:[NSExpression mgl_expressionForString:MGLExpressionStyleFunctionZoomLevel]
+        NSExpression *functionExpression = [NSExpression mgl_expressionForStepFunction:[NSExpression expressionForVariable:MGLExpressionStyleFunctionZoomLevel]
                                                                      defaultExpression:constantExpression
                                                                                  stops:[NSExpression expressionWithFormat:@"%@", @{@18: constantExpression}]];
         layer.rasterSaturation = functionExpression;
diff --git a/platform/darwin/test/MGLStyleLayerTests.mm.ejs b/platform/darwin/test/MGLStyleLayerTests.mm.ejs
index 4a6b730097..dcae36bf18 100644
--- a/platform/darwin/test/MGLStyleLayerTests.mm.ejs
+++ b/platform/darwin/test/MGLStyleLayerTests.mm.ejs
@@ -88,7 +88,7 @@
 <% } else { -%>
         constantExpression = [NSExpression expressionWithFormat:<%- objCTestValue(property, type, false, 3) %>];
 <% } -%>
-        NSExpression *functionExpression = [NSExpression mgl_expressionForStepFunction:[NSExpression mgl_expressionForString:MGLExpressionStyleFunctionZoomLevel]
+        NSExpression *functionExpression = [NSExpression mgl_expressionForStepFunction:[NSExpression expressionForVariable:MGLExpressionStyleFunctionZoomLevel]
                                                                      defaultExpression:constantExpression
                                                                                  stops:[NSExpression expressionWithFormat:@"%@", @{@18: constantExpression}]];
         layer.<%- objCName(property) %> = functionExpression;
diff --git a/platform/darwin/test/MGLSymbolStyleLayerTests.mm b/platform/darwin/test/MGLSymbolStyleLayerTests.mm
index fe31565fd4..9c88003c15 100644
--- a/platform/darwin/test/MGLSymbolStyleLayerTests.mm
+++ b/platform/darwin/test/MGLSymbolStyleLayerTests.mm
@@ -63,7 +63,7 @@
                               @"iconAllowsOverlap should round-trip constant value expressions.");
 
         constantExpression = [NSExpression mgl_expressionForValue:@YES];
-        NSExpression *functionExpression = [NSExpression mgl_expressionForStepFunction:[NSExpression mgl_expressionForString:MGLExpressionStyleFunctionZoomLevel]
+        NSExpression *functionExpression = [NSExpression mgl_expressionForStepFunction:[NSExpression expressionForVariable:MGLExpressionStyleFunctionZoomLevel]
                                                                      defaultExpression:constantExpression
                                                                                  stops:[NSExpression expressionWithFormat:@"%@", @{@18: constantExpression}]];
         layer.iconAllowsOverlap = functionExpression;
@@ -112,7 +112,7 @@
                               @"iconAnchor should round-trip constant value expressions.");
 
         constantExpression = [NSExpression expressionWithFormat:@"'bottom-right'"];
-        NSExpression *functionExpression = [NSExpression mgl_expressionForStepFunction:[NSExpression mgl_expressionForString:MGLExpressionStyleFunctionZoomLevel]
+        NSExpression *functionExpression = [NSExpression mgl_expressionForStepFunction:[NSExpression expressionForVariable:MGLExpressionStyleFunctionZoomLevel]
                                                                      defaultExpression:constantExpression
                                                                                  stops:[NSExpression expressionWithFormat:@"%@", @{@18: constantExpression}]];
         layer.iconAnchor = functionExpression;
@@ -152,7 +152,7 @@
                               @"iconIgnoresPlacement should round-trip constant value expressions.");
 
         constantExpression = [NSExpression mgl_expressionForValue:@YES];
-        NSExpression *functionExpression = [NSExpression mgl_expressionForStepFunction:[NSExpression mgl_expressionForString:MGLExpressionStyleFunctionZoomLevel]
+        NSExpression *functionExpression = [NSExpression mgl_expressionForStepFunction:[NSExpression expressionForVariable:MGLExpressionStyleFunctionZoomLevel]
                                                                      defaultExpression:constantExpression
                                                                                  stops:[NSExpression expressionWithFormat:@"%@", @{@18: constantExpression}]];
         layer.iconIgnoresPlacement = functionExpression;
@@ -192,7 +192,7 @@
                       @"icon-image should be unset initially.");
         NSExpression *defaultExpression = layer.iconImageName;
 
-        NSExpression *constantExpression = [NSExpression mgl_expressionForString:@"'Icon Image'"];
+        NSExpression *constantExpression = [NSExpression mgl_expressionForString:@"Icon Image"];
         layer.iconImageName = constantExpression;
         mbgl::style::DataDrivenPropertyValue<std::string> propertyValue = { "Icon Image" };
         XCTAssertEqual(rawLayer->getIconImage(), propertyValue,
@@ -200,8 +200,8 @@
         XCTAssertEqualObjects(layer.iconImageName, constantExpression,
                               @"iconImageName should round-trip constant value expressions.");
 
-        constantExpression = [NSExpression mgl_expressionForString:@"'Icon Image'"];
-        NSExpression *functionExpression = [NSExpression mgl_expressionForStepFunction:[NSExpression mgl_expressionForString:MGLExpressionStyleFunctionZoomLevel]
+        constantExpression = [NSExpression mgl_expressionForString:@"Icon Image"];
+        NSExpression *functionExpression = [NSExpression mgl_expressionForStepFunction:[NSExpression expressionForVariable:MGLExpressionStyleFunctionZoomLevel]
                                                                      defaultExpression:constantExpression
                                                                                  stops:[NSExpression expressionWithFormat:@"%@", @{@18: constantExpression}]];
         layer.iconImageName = functionExpression;
@@ -247,7 +247,7 @@
                               @"iconOffset should round-trip constant value expressions.");
 
         constantExpression = [NSExpression expressionWithFormat:@"{1, 1}"];
-        NSExpression *functionExpression = [NSExpression mgl_expressionForStepFunction:[NSExpression mgl_expressionForString:MGLExpressionStyleFunctionZoomLevel]
+        NSExpression *functionExpression = [NSExpression mgl_expressionForStepFunction:[NSExpression expressionForVariable:MGLExpressionStyleFunctionZoomLevel]
                                                                      defaultExpression:constantExpression
                                                                                  stops:[NSExpression expressionWithFormat:@"%@", @{@18: constantExpression}]];
         layer.iconOffset = functionExpression;
@@ -315,7 +315,7 @@
                               @"iconOptional should round-trip constant value expressions.");
 
         constantExpression = [NSExpression mgl_expressionForValue:@YES];
-        NSExpression *functionExpression = [NSExpression mgl_expressionForStepFunction:[NSExpression mgl_expressionForString:MGLExpressionStyleFunctionZoomLevel]
+        NSExpression *functionExpression = [NSExpression mgl_expressionForStepFunction:[NSExpression expressionForVariable:MGLExpressionStyleFunctionZoomLevel]
                                                                      defaultExpression:constantExpression
                                                                                  stops:[NSExpression expressionWithFormat:@"%@", @{@18: constantExpression}]];
         layer.iconOptional = functionExpression;
@@ -364,7 +364,7 @@
                               @"iconPadding should round-trip constant value expressions.");
 
         constantExpression = [NSExpression mgl_expressionForValue:@0xff];
-        NSExpression *functionExpression = [NSExpression mgl_expressionForStepFunction:[NSExpression mgl_expressionForString:MGLExpressionStyleFunctionZoomLevel]
+        NSExpression *functionExpression = [NSExpression mgl_expressionForStepFunction:[NSExpression expressionForVariable:MGLExpressionStyleFunctionZoomLevel]
                                                                      defaultExpression:constantExpression
                                                                                  stops:[NSExpression expressionWithFormat:@"%@", @{@18: constantExpression}]];
         layer.iconPadding = functionExpression;
@@ -413,7 +413,7 @@
                               @"iconPitchAlignment should round-trip constant value expressions.");
 
         constantExpression = [NSExpression expressionWithFormat:@"'auto'"];
-        NSExpression *functionExpression = [NSExpression mgl_expressionForStepFunction:[NSExpression mgl_expressionForString:MGLExpressionStyleFunctionZoomLevel]
+        NSExpression *functionExpression = [NSExpression mgl_expressionForStepFunction:[NSExpression expressionForVariable:MGLExpressionStyleFunctionZoomLevel]
                                                                      defaultExpression:constantExpression
                                                                                  stops:[NSExpression expressionWithFormat:@"%@", @{@18: constantExpression}]];
         layer.iconPitchAlignment = functionExpression;
@@ -462,7 +462,7 @@
                               @"iconRotation should round-trip constant value expressions.");
 
         constantExpression = [NSExpression mgl_expressionForValue:@0xff];
-        NSExpression *functionExpression = [NSExpression mgl_expressionForStepFunction:[NSExpression mgl_expressionForString:MGLExpressionStyleFunctionZoomLevel]
+        NSExpression *functionExpression = [NSExpression mgl_expressionForStepFunction:[NSExpression expressionForVariable:MGLExpressionStyleFunctionZoomLevel]
                                                                      defaultExpression:constantExpression
                                                                                  stops:[NSExpression expressionWithFormat:@"%@", @{@18: constantExpression}]];
         layer.iconRotation = functionExpression;
@@ -530,7 +530,7 @@
                               @"iconRotationAlignment should round-trip constant value expressions.");
 
         constantExpression = [NSExpression expressionWithFormat:@"'auto'"];
-        NSExpression *functionExpression = [NSExpression mgl_expressionForStepFunction:[NSExpression mgl_expressionForString:MGLExpressionStyleFunctionZoomLevel]
+        NSExpression *functionExpression = [NSExpression mgl_expressionForStepFunction:[NSExpression expressionForVariable:MGLExpressionStyleFunctionZoomLevel]
                                                                      defaultExpression:constantExpression
                                                                                  stops:[NSExpression expressionWithFormat:@"%@", @{@18: constantExpression}]];
         layer.iconRotationAlignment = functionExpression;
@@ -579,7 +579,7 @@
                               @"iconScale should round-trip constant value expressions.");
 
         constantExpression = [NSExpression mgl_expressionForValue:@0xff];
-        NSExpression *functionExpression = [NSExpression mgl_expressionForStepFunction:[NSExpression mgl_expressionForString:MGLExpressionStyleFunctionZoomLevel]
+        NSExpression *functionExpression = [NSExpression mgl_expressionForStepFunction:[NSExpression expressionForVariable:MGLExpressionStyleFunctionZoomLevel]
                                                                      defaultExpression:constantExpression
                                                                                  stops:[NSExpression expressionWithFormat:@"%@", @{@18: constantExpression}]];
         layer.iconScale = functionExpression;
@@ -647,7 +647,7 @@
                               @"iconTextFit should round-trip constant value expressions.");
 
         constantExpression = [NSExpression expressionWithFormat:@"'both'"];
-        NSExpression *functionExpression = [NSExpression mgl_expressionForStepFunction:[NSExpression mgl_expressionForString:MGLExpressionStyleFunctionZoomLevel]
+        NSExpression *functionExpression = [NSExpression mgl_expressionForStepFunction:[NSExpression expressionForVariable:MGLExpressionStyleFunctionZoomLevel]
                                                                      defaultExpression:constantExpression
                                                                                  stops:[NSExpression expressionWithFormat:@"%@", @{@18: constantExpression}]];
         layer.iconTextFit = functionExpression;
@@ -702,7 +702,7 @@
                               @"iconTextFitPadding should round-trip constant value expressions.");
 
         constantExpression = [NSExpression expressionWithFormat:@"{1, 1, 1, 1}"];
-        NSExpression *functionExpression = [NSExpression mgl_expressionForStepFunction:[NSExpression mgl_expressionForString:MGLExpressionStyleFunctionZoomLevel]
+        NSExpression *functionExpression = [NSExpression mgl_expressionForStepFunction:[NSExpression expressionForVariable:MGLExpressionStyleFunctionZoomLevel]
                                                                      defaultExpression:constantExpression
                                                                                  stops:[NSExpression expressionWithFormat:@"%@", @{@18: constantExpression}]];
         layer.iconTextFitPadding = functionExpression;
@@ -751,7 +751,7 @@
                               @"keepsIconUpright should round-trip constant value expressions.");
 
         constantExpression = [NSExpression mgl_expressionForValue:@YES];
-        NSExpression *functionExpression = [NSExpression mgl_expressionForStepFunction:[NSExpression mgl_expressionForString:MGLExpressionStyleFunctionZoomLevel]
+        NSExpression *functionExpression = [NSExpression mgl_expressionForStepFunction:[NSExpression expressionForVariable:MGLExpressionStyleFunctionZoomLevel]
                                                                      defaultExpression:constantExpression
                                                                                  stops:[NSExpression expressionWithFormat:@"%@", @{@18: constantExpression}]];
         layer.keepsIconUpright = functionExpression;
@@ -800,7 +800,7 @@
                               @"keepsTextUpright should round-trip constant value expressions.");
 
         constantExpression = [NSExpression mgl_expressionForValue:@NO];
-        NSExpression *functionExpression = [NSExpression mgl_expressionForStepFunction:[NSExpression mgl_expressionForString:MGLExpressionStyleFunctionZoomLevel]
+        NSExpression *functionExpression = [NSExpression mgl_expressionForStepFunction:[NSExpression expressionForVariable:MGLExpressionStyleFunctionZoomLevel]
                                                                      defaultExpression:constantExpression
                                                                                  stops:[NSExpression expressionWithFormat:@"%@", @{@18: constantExpression}]];
         layer.keepsTextUpright = functionExpression;
@@ -849,7 +849,7 @@
                               @"maximumTextAngle should round-trip constant value expressions.");
 
         constantExpression = [NSExpression mgl_expressionForValue:@0xff];
-        NSExpression *functionExpression = [NSExpression mgl_expressionForStepFunction:[NSExpression mgl_expressionForString:MGLExpressionStyleFunctionZoomLevel]
+        NSExpression *functionExpression = [NSExpression mgl_expressionForStepFunction:[NSExpression expressionForVariable:MGLExpressionStyleFunctionZoomLevel]
                                                                      defaultExpression:constantExpression
                                                                                  stops:[NSExpression expressionWithFormat:@"%@", @{@18: constantExpression}]];
         layer.maximumTextAngle = functionExpression;
@@ -898,7 +898,7 @@
                               @"maximumTextWidth should round-trip constant value expressions.");
 
         constantExpression = [NSExpression mgl_expressionForValue:@0xff];
-        NSExpression *functionExpression = [NSExpression mgl_expressionForStepFunction:[NSExpression mgl_expressionForString:MGLExpressionStyleFunctionZoomLevel]
+        NSExpression *functionExpression = [NSExpression mgl_expressionForStepFunction:[NSExpression expressionForVariable:MGLExpressionStyleFunctionZoomLevel]
                                                                      defaultExpression:constantExpression
                                                                                  stops:[NSExpression expressionWithFormat:@"%@", @{@18: constantExpression}]];
         layer.maximumTextWidth = functionExpression;
@@ -966,7 +966,7 @@
                               @"symbolAvoidsEdges should round-trip constant value expressions.");
 
         constantExpression = [NSExpression mgl_expressionForValue:@YES];
-        NSExpression *functionExpression = [NSExpression mgl_expressionForStepFunction:[NSExpression mgl_expressionForString:MGLExpressionStyleFunctionZoomLevel]
+        NSExpression *functionExpression = [NSExpression mgl_expressionForStepFunction:[NSExpression expressionForVariable:MGLExpressionStyleFunctionZoomLevel]
                                                                      defaultExpression:constantExpression
                                                                                  stops:[NSExpression expressionWithFormat:@"%@", @{@18: constantExpression}]];
         layer.symbolAvoidsEdges = functionExpression;
@@ -1015,7 +1015,7 @@
                               @"symbolPlacement should round-trip constant value expressions.");
 
         constantExpression = [NSExpression expressionWithFormat:@"'line'"];
-        NSExpression *functionExpression = [NSExpression mgl_expressionForStepFunction:[NSExpression mgl_expressionForString:MGLExpressionStyleFunctionZoomLevel]
+        NSExpression *functionExpression = [NSExpression mgl_expressionForStepFunction:[NSExpression expressionForVariable:MGLExpressionStyleFunctionZoomLevel]
                                                                      defaultExpression:constantExpression
                                                                                  stops:[NSExpression expressionWithFormat:@"%@", @{@18: constantExpression}]];
         layer.symbolPlacement = functionExpression;
@@ -1064,7 +1064,7 @@
                               @"symbolSpacing should round-trip constant value expressions.");
 
         constantExpression = [NSExpression mgl_expressionForValue:@0xff];
-        NSExpression *functionExpression = [NSExpression mgl_expressionForStepFunction:[NSExpression mgl_expressionForString:MGLExpressionStyleFunctionZoomLevel]
+        NSExpression *functionExpression = [NSExpression mgl_expressionForStepFunction:[NSExpression expressionForVariable:MGLExpressionStyleFunctionZoomLevel]
                                                                      defaultExpression:constantExpression
                                                                                  stops:[NSExpression expressionWithFormat:@"%@", @{@18: constantExpression}]];
         layer.symbolSpacing = functionExpression;
@@ -1104,7 +1104,7 @@
                       @"text-field should be unset initially.");
         NSExpression *defaultExpression = layer.text;
 
-        NSExpression *constantExpression = [NSExpression mgl_expressionForString:@"'Text Field'"];
+        NSExpression *constantExpression = [NSExpression mgl_expressionForString:@"Text Field"];
         layer.text = constantExpression;
         mbgl::style::DataDrivenPropertyValue<std::string> propertyValue = { "Text Field" };
         XCTAssertEqual(rawLayer->getTextField(), propertyValue,
@@ -1112,8 +1112,8 @@
         XCTAssertEqualObjects(layer.text, constantExpression,
                               @"text should round-trip constant value expressions.");
 
-        constantExpression = [NSExpression mgl_expressionForString:@"'Text Field'"];
-        NSExpression *functionExpression = [NSExpression mgl_expressionForStepFunction:[NSExpression mgl_expressionForString:MGLExpressionStyleFunctionZoomLevel]
+        constantExpression = [NSExpression mgl_expressionForString:@"Text Field"];
+        NSExpression *functionExpression = [NSExpression mgl_expressionForStepFunction:[NSExpression expressionForVariable:MGLExpressionStyleFunctionZoomLevel]
                                                                      defaultExpression:constantExpression
                                                                                  stops:[NSExpression expressionWithFormat:@"%@", @{@18: constantExpression}]];
         layer.text = functionExpression;
@@ -1153,7 +1153,7 @@
                               @"textAllowsOverlap should round-trip constant value expressions.");
 
         constantExpression = [NSExpression mgl_expressionForValue:@YES];
-        NSExpression *functionExpression = [NSExpression mgl_expressionForStepFunction:[NSExpression mgl_expressionForString:MGLExpressionStyleFunctionZoomLevel]
+        NSExpression *functionExpression = [NSExpression mgl_expressionForStepFunction:[NSExpression expressionForVariable:MGLExpressionStyleFunctionZoomLevel]
                                                                      defaultExpression:constantExpression
                                                                                  stops:[NSExpression expressionWithFormat:@"%@", @{@18: constantExpression}]];
         layer.textAllowsOverlap = functionExpression;
@@ -1202,7 +1202,7 @@
                               @"textAnchor should round-trip constant value expressions.");
 
         constantExpression = [NSExpression expressionWithFormat:@"'bottom-right'"];
-        NSExpression *functionExpression = [NSExpression mgl_expressionForStepFunction:[NSExpression mgl_expressionForString:MGLExpressionStyleFunctionZoomLevel]
+        NSExpression *functionExpression = [NSExpression mgl_expressionForStepFunction:[NSExpression expressionForVariable:MGLExpressionStyleFunctionZoomLevel]
                                                                      defaultExpression:constantExpression
                                                                                  stops:[NSExpression expressionWithFormat:@"%@", @{@18: constantExpression}]];
         layer.textAnchor = functionExpression;
@@ -1242,7 +1242,7 @@
                               @"textFontNames should round-trip constant value expressions.");
 
         constantExpression = [NSExpression expressionWithFormat:@"{'Text Font', 'Tnof Txet'}"];
-        NSExpression *functionExpression = [NSExpression mgl_expressionForStepFunction:[NSExpression mgl_expressionForString:MGLExpressionStyleFunctionZoomLevel]
+        NSExpression *functionExpression = [NSExpression mgl_expressionForStepFunction:[NSExpression expressionForVariable:MGLExpressionStyleFunctionZoomLevel]
                                                                      defaultExpression:constantExpression
                                                                                  stops:[NSExpression expressionWithFormat:@"%@", @{@18: constantExpression}]];
         layer.textFontNames = functionExpression;
@@ -1282,7 +1282,7 @@
                               @"textFontSize should round-trip constant value expressions.");
 
         constantExpression = [NSExpression mgl_expressionForValue:@0xff];
-        NSExpression *functionExpression = [NSExpression mgl_expressionForStepFunction:[NSExpression mgl_expressionForString:MGLExpressionStyleFunctionZoomLevel]
+        NSExpression *functionExpression = [NSExpression mgl_expressionForStepFunction:[NSExpression expressionForVariable:MGLExpressionStyleFunctionZoomLevel]
                                                                      defaultExpression:constantExpression
                                                                                  stops:[NSExpression expressionWithFormat:@"%@", @{@18: constantExpression}]];
         layer.textFontSize = functionExpression;
@@ -1350,7 +1350,7 @@
                               @"textIgnoresPlacement should round-trip constant value expressions.");
 
         constantExpression = [NSExpression mgl_expressionForValue:@YES];
-        NSExpression *functionExpression = [NSExpression mgl_expressionForStepFunction:[NSExpression mgl_expressionForString:MGLExpressionStyleFunctionZoomLevel]
+        NSExpression *functionExpression = [NSExpression mgl_expressionForStepFunction:[NSExpression expressionForVariable:MGLExpressionStyleFunctionZoomLevel]
                                                                      defaultExpression:constantExpression
                                                                                  stops:[NSExpression expressionWithFormat:@"%@", @{@18: constantExpression}]];
         layer.textIgnoresPlacement = functionExpression;
@@ -1399,7 +1399,7 @@
                               @"textJustification should round-trip constant value expressions.");
 
         constantExpression = [NSExpression expressionWithFormat:@"'right'"];
-        NSExpression *functionExpression = [NSExpression mgl_expressionForStepFunction:[NSExpression mgl_expressionForString:MGLExpressionStyleFunctionZoomLevel]
+        NSExpression *functionExpression = [NSExpression mgl_expressionForStepFunction:[NSExpression expressionForVariable:MGLExpressionStyleFunctionZoomLevel]
                                                                      defaultExpression:constantExpression
                                                                                  stops:[NSExpression expressionWithFormat:@"%@", @{@18: constantExpression}]];
         layer.textJustification = functionExpression;
@@ -1439,7 +1439,7 @@
                               @"textLetterSpacing should round-trip constant value expressions.");
 
         constantExpression = [NSExpression mgl_expressionForValue:@0xff];
-        NSExpression *functionExpression = [NSExpression mgl_expressionForStepFunction:[NSExpression mgl_expressionForString:MGLExpressionStyleFunctionZoomLevel]
+        NSExpression *functionExpression = [NSExpression mgl_expressionForStepFunction:[NSExpression expressionForVariable:MGLExpressionStyleFunctionZoomLevel]
                                                                      defaultExpression:constantExpression
                                                                                  stops:[NSExpression expressionWithFormat:@"%@", @{@18: constantExpression}]];
         layer.textLetterSpacing = functionExpression;
@@ -1507,7 +1507,7 @@
                               @"textLineHeight should round-trip constant value expressions.");
 
         constantExpression = [NSExpression mgl_expressionForValue:@0xff];
-        NSExpression *functionExpression = [NSExpression mgl_expressionForStepFunction:[NSExpression mgl_expressionForString:MGLExpressionStyleFunctionZoomLevel]
+        NSExpression *functionExpression = [NSExpression mgl_expressionForStepFunction:[NSExpression expressionForVariable:MGLExpressionStyleFunctionZoomLevel]
                                                                      defaultExpression:constantExpression
                                                                                  stops:[NSExpression expressionWithFormat:@"%@", @{@18: constantExpression}]];
         layer.textLineHeight = functionExpression;
@@ -1562,7 +1562,7 @@
                               @"textOffset should round-trip constant value expressions.");
 
         constantExpression = [NSExpression expressionWithFormat:@"{1, 1}"];
-        NSExpression *functionExpression = [NSExpression mgl_expressionForStepFunction:[NSExpression mgl_expressionForString:MGLExpressionStyleFunctionZoomLevel]
+        NSExpression *functionExpression = [NSExpression mgl_expressionForStepFunction:[NSExpression expressionForVariable:MGLExpressionStyleFunctionZoomLevel]
                                                                      defaultExpression:constantExpression
                                                                                  stops:[NSExpression expressionWithFormat:@"%@", @{@18: constantExpression}]];
         layer.textOffset = functionExpression;
@@ -1630,7 +1630,7 @@
                               @"textOptional should round-trip constant value expressions.");
 
         constantExpression = [NSExpression mgl_expressionForValue:@YES];
-        NSExpression *functionExpression = [NSExpression mgl_expressionForStepFunction:[NSExpression mgl_expressionForString:MGLExpressionStyleFunctionZoomLevel]
+        NSExpression *functionExpression = [NSExpression mgl_expressionForStepFunction:[NSExpression expressionForVariable:MGLExpressionStyleFunctionZoomLevel]
                                                                      defaultExpression:constantExpression
                                                                                  stops:[NSExpression expressionWithFormat:@"%@", @{@18: constantExpression}]];
         layer.textOptional = functionExpression;
@@ -1679,7 +1679,7 @@
                               @"textPadding should round-trip constant value expressions.");
 
         constantExpression = [NSExpression mgl_expressionForValue:@0xff];
-        NSExpression *functionExpression = [NSExpression mgl_expressionForStepFunction:[NSExpression mgl_expressionForString:MGLExpressionStyleFunctionZoomLevel]
+        NSExpression *functionExpression = [NSExpression mgl_expressionForStepFunction:[NSExpression expressionForVariable:MGLExpressionStyleFunctionZoomLevel]
                                                                      defaultExpression:constantExpression
                                                                                  stops:[NSExpression expressionWithFormat:@"%@", @{@18: constantExpression}]];
         layer.textPadding = functionExpression;
@@ -1728,7 +1728,7 @@
                               @"textPitchAlignment should round-trip constant value expressions.");
 
         constantExpression = [NSExpression expressionWithFormat:@"'auto'"];
-        NSExpression *functionExpression = [NSExpression mgl_expressionForStepFunction:[NSExpression mgl_expressionForString:MGLExpressionStyleFunctionZoomLevel]
+        NSExpression *functionExpression = [NSExpression mgl_expressionForStepFunction:[NSExpression expressionForVariable:MGLExpressionStyleFunctionZoomLevel]
                                                                      defaultExpression:constantExpression
                                                                                  stops:[NSExpression expressionWithFormat:@"%@", @{@18: constantExpression}]];
         layer.textPitchAlignment = functionExpression;
@@ -1777,7 +1777,7 @@
                               @"textRotation should round-trip constant value expressions.");
 
         constantExpression = [NSExpression mgl_expressionForValue:@0xff];
-        NSExpression *functionExpression = [NSExpression mgl_expressionForStepFunction:[NSExpression mgl_expressionForString:MGLExpressionStyleFunctionZoomLevel]
+        NSExpression *functionExpression = [NSExpression mgl_expressionForStepFunction:[NSExpression expressionForVariable:MGLExpressionStyleFunctionZoomLevel]
                                                                      defaultExpression:constantExpression
                                                                                  stops:[NSExpression expressionWithFormat:@"%@", @{@18: constantExpression}]];
         layer.textRotation = functionExpression;
@@ -1845,7 +1845,7 @@
                               @"textRotationAlignment should round-trip constant value expressions.");
 
         constantExpression = [NSExpression expressionWithFormat:@"'auto'"];
-        NSExpression *functionExpression = [NSExpression mgl_expressionForStepFunction:[NSExpression mgl_expressionForString:MGLExpressionStyleFunctionZoomLevel]
+        NSExpression *functionExpression = [NSExpression mgl_expressionForStepFunction:[NSExpression expressionForVariable:MGLExpressionStyleFunctionZoomLevel]
                                                                      defaultExpression:constantExpression
                                                                                  stops:[NSExpression expressionWithFormat:@"%@", @{@18: constantExpression}]];
         layer.textRotationAlignment = functionExpression;
@@ -1894,7 +1894,7 @@
                               @"textTransform should round-trip constant value expressions.");
 
         constantExpression = [NSExpression expressionWithFormat:@"'lowercase'"];
-        NSExpression *functionExpression = [NSExpression mgl_expressionForStepFunction:[NSExpression mgl_expressionForString:MGLExpressionStyleFunctionZoomLevel]
+        NSExpression *functionExpression = [NSExpression mgl_expressionForStepFunction:[NSExpression expressionForVariable:MGLExpressionStyleFunctionZoomLevel]
                                                                      defaultExpression:constantExpression
                                                                                  stops:[NSExpression expressionWithFormat:@"%@", @{@18: constantExpression}]];
         layer.textTransform = functionExpression;
@@ -1934,7 +1934,7 @@
                               @"iconColor should round-trip constant value expressions.");
 
         constantExpression = [NSExpression mgl_expressionForColor:[MGLColor redColor]];
-        NSExpression *functionExpression = [NSExpression mgl_expressionForStepFunction:[NSExpression mgl_expressionForString:MGLExpressionStyleFunctionZoomLevel]
+        NSExpression *functionExpression = [NSExpression mgl_expressionForStepFunction:[NSExpression expressionForVariable:MGLExpressionStyleFunctionZoomLevel]
                                                                      defaultExpression:constantExpression
                                                                                  stops:[NSExpression expressionWithFormat:@"%@", @{@18: constantExpression}]];
         layer.iconColor = functionExpression;
@@ -2011,7 +2011,7 @@
                               @"iconHaloBlur should round-trip constant value expressions.");
 
         constantExpression = [NSExpression mgl_expressionForValue:@0xff];
-        NSExpression *functionExpression = [NSExpression mgl_expressionForStepFunction:[NSExpression mgl_expressionForString:MGLExpressionStyleFunctionZoomLevel]
+        NSExpression *functionExpression = [NSExpression mgl_expressionForStepFunction:[NSExpression expressionForVariable:MGLExpressionStyleFunctionZoomLevel]
                                                                      defaultExpression:constantExpression
                                                                                  stops:[NSExpression expressionWithFormat:@"%@", @{@18: constantExpression}]];
         layer.iconHaloBlur = functionExpression;
@@ -2088,7 +2088,7 @@
                               @"iconHaloColor should round-trip constant value expressions.");
 
         constantExpression = [NSExpression mgl_expressionForColor:[MGLColor redColor]];
-        NSExpression *functionExpression = [NSExpression mgl_expressionForStepFunction:[NSExpression mgl_expressionForString:MGLExpressionStyleFunctionZoomLevel]
+        NSExpression *functionExpression = [NSExpression mgl_expressionForStepFunction:[NSExpression expressionForVariable:MGLExpressionStyleFunctionZoomLevel]
                                                                      defaultExpression:constantExpression
                                                                                  stops:[NSExpression expressionWithFormat:@"%@", @{@18: constantExpression}]];
         layer.iconHaloColor = functionExpression;
@@ -2165,7 +2165,7 @@
                               @"iconHaloWidth should round-trip constant value expressions.");
 
         constantExpression = [NSExpression mgl_expressionForValue:@0xff];
-        NSExpression *functionExpression = [NSExpression mgl_expressionForStepFunction:[NSExpression mgl_expressionForString:MGLExpressionStyleFunctionZoomLevel]
+        NSExpression *functionExpression = [NSExpression mgl_expressionForStepFunction:[NSExpression expressionForVariable:MGLExpressionStyleFunctionZoomLevel]
                                                                      defaultExpression:constantExpression
                                                                                  stops:[NSExpression expressionWithFormat:@"%@", @{@18: constantExpression}]];
         layer.iconHaloWidth = functionExpression;
@@ -2242,7 +2242,7 @@
                               @"iconOpacity should round-trip constant value expressions.");
 
         constantExpression = [NSExpression mgl_expressionForValue:@0xff];
-        NSExpression *functionExpression = [NSExpression mgl_expressionForStepFunction:[NSExpression mgl_expressionForString:MGLExpressionStyleFunctionZoomLevel]
+        NSExpression *functionExpression = [NSExpression mgl_expressionForStepFunction:[NSExpression expressionForVariable:MGLExpressionStyleFunctionZoomLevel]
                                                                      defaultExpression:constantExpression
                                                                                  stops:[NSExpression expressionWithFormat:@"%@", @{@18: constantExpression}]];
         layer.iconOpacity = functionExpression;
@@ -2325,7 +2325,7 @@
                               @"iconTranslation should round-trip constant value expressions.");
 
         constantExpression = [NSExpression expressionWithFormat:@"{1, 1}"];
-        NSExpression *functionExpression = [NSExpression mgl_expressionForStepFunction:[NSExpression mgl_expressionForString:MGLExpressionStyleFunctionZoomLevel]
+        NSExpression *functionExpression = [NSExpression mgl_expressionForStepFunction:[NSExpression expressionForVariable:MGLExpressionStyleFunctionZoomLevel]
                                                                      defaultExpression:constantExpression
                                                                                  stops:[NSExpression expressionWithFormat:@"%@", @{@18: constantExpression}]];
         layer.iconTranslation = functionExpression;
@@ -2374,7 +2374,7 @@
                               @"iconTranslationAnchor should round-trip constant value expressions.");
 
         constantExpression = [NSExpression expressionWithFormat:@"'viewport'"];
-        NSExpression *functionExpression = [NSExpression mgl_expressionForStepFunction:[NSExpression mgl_expressionForString:MGLExpressionStyleFunctionZoomLevel]
+        NSExpression *functionExpression = [NSExpression mgl_expressionForStepFunction:[NSExpression expressionForVariable:MGLExpressionStyleFunctionZoomLevel]
                                                                      defaultExpression:constantExpression
                                                                                  stops:[NSExpression expressionWithFormat:@"%@", @{@18: constantExpression}]];
         layer.iconTranslationAnchor = functionExpression;
@@ -2423,7 +2423,7 @@
                               @"textColor should round-trip constant value expressions.");
 
         constantExpression = [NSExpression mgl_expressionForColor:[MGLColor redColor]];
-        NSExpression *functionExpression = [NSExpression mgl_expressionForStepFunction:[NSExpression mgl_expressionForString:MGLExpressionStyleFunctionZoomLevel]
+        NSExpression *functionExpression = [NSExpression mgl_expressionForStepFunction:[NSExpression expressionForVariable:MGLExpressionStyleFunctionZoomLevel]
                                                                      defaultExpression:constantExpression
                                                                                  stops:[NSExpression expressionWithFormat:@"%@", @{@18: constantExpression}]];
         layer.textColor = functionExpression;
@@ -2500,7 +2500,7 @@
                               @"textHaloBlur should round-trip constant value expressions.");
 
         constantExpression = [NSExpression mgl_expressionForValue:@0xff];
-        NSExpression *functionExpression = [NSExpression mgl_expressionForStepFunction:[NSExpression mgl_expressionForString:MGLExpressionStyleFunctionZoomLevel]
+        NSExpression *functionExpression = [NSExpression mgl_expressionForStepFunction:[NSExpression expressionForVariable:MGLExpressionStyleFunctionZoomLevel]
                                                                      defaultExpression:constantExpression
                                                                                  stops:[NSExpression expressionWithFormat:@"%@", @{@18: constantExpression}]];
         layer.textHaloBlur = functionExpression;
@@ -2577,7 +2577,7 @@
                               @"textHaloColor should round-trip constant value expressions.");
 
         constantExpression = [NSExpression mgl_expressionForColor:[MGLColor redColor]];
-        NSExpression *functionExpression = [NSExpression mgl_expressionForStepFunction:[NSExpression mgl_expressionForString:MGLExpressionStyleFunctionZoomLevel]
+        NSExpression *functionExpression = [NSExpression mgl_expressionForStepFunction:[NSExpression expressionForVariable:MGLExpressionStyleFunctionZoomLevel]
                                                                      defaultExpression:constantExpression
                                                                                  stops:[NSExpression expressionWithFormat:@"%@", @{@18: constantExpression}]];
         layer.textHaloColor = functionExpression;
@@ -2654,7 +2654,7 @@
                               @"textHaloWidth should round-trip constant value expressions.");
 
         constantExpression = [NSExpression mgl_expressionForValue:@0xff];
-        NSExpression *functionExpression = [NSExpression mgl_expressionForStepFunction:[NSExpression mgl_expressionForString:MGLExpressionStyleFunctionZoomLevel]
+        NSExpression *functionExpression = [NSExpression mgl_expressionForStepFunction:[NSExpression expressionForVariable:MGLExpressionStyleFunctionZoomLevel]
                                                                      defaultExpression:constantExpression
                                                                                  stops:[NSExpression expressionWithFormat:@"%@", @{@18: constantExpression}]];
         layer.textHaloWidth = functionExpression;
@@ -2731,7 +2731,7 @@
                               @"textOpacity should round-trip constant value expressions.");
 
         constantExpression = [NSExpression mgl_expressionForValue:@0xff];
-        NSExpression *functionExpression = [NSExpression mgl_expressionForStepFunction:[NSExpression mgl_expressionForString:MGLExpressionStyleFunctionZoomLevel]
+        NSExpression *functionExpression = [NSExpression mgl_expressionForStepFunction:[NSExpression expressionForVariable:MGLExpressionStyleFunctionZoomLevel]
                                                                      defaultExpression:constantExpression
                                                                                  stops:[NSExpression expressionWithFormat:@"%@", @{@18: constantExpression}]];
         layer.textOpacity = functionExpression;
@@ -2814,7 +2814,7 @@
                               @"textTranslation should round-trip constant value expressions.");
 
         constantExpression = [NSExpression expressionWithFormat:@"{1, 1}"];
-        NSExpression *functionExpression = [NSExpression mgl_expressionForStepFunction:[NSExpression mgl_expressionForString:MGLExpressionStyleFunctionZoomLevel]
+        NSExpression *functionExpression = [NSExpression mgl_expressionForStepFunction:[NSExpression expressionForVariable:MGLExpressionStyleFunctionZoomLevel]
                                                                      defaultExpression:constantExpression
                                                                                  stops:[NSExpression expressionWithFormat:@"%@", @{@18: constantExpression}]];
         layer.textTranslation = functionExpression;
@@ -2863,7 +2863,7 @@
                               @"textTranslationAnchor should round-trip constant value expressions.");
 
         constantExpression = [NSExpression expressionWithFormat:@"'viewport'"];
-        NSExpression *functionExpression = [NSExpression mgl_expressionForStepFunction:[NSExpression mgl_expressionForString:MGLExpressionStyleFunctionZoomLevel]
+        NSExpression *functionExpression = [NSExpression mgl_expressionForStepFunction:[NSExpression expressionForVariable:MGLExpressionStyleFunctionZoomLevel]
                                                                      defaultExpression:constantExpression
                                                                                  stops:[NSExpression expressionWithFormat:@"%@", @{@18: constantExpression}]];
         layer.textTranslationAnchor = functionExpression;
diff --git a/platform/ios/app/MBXViewController.m b/platform/ios/app/MBXViewController.m
index daff2a64e9..bb5a5bd72a 100644
--- a/platform/ios/app/MBXViewController.m
+++ b/platform/ios/app/MBXViewController.m
@@ -1462,7 +1462,7 @@ typedef NS_ENUM(NSInteger, MBXSettingsMiscellaneousRows) {
 
     // source, identity function that sets any feature with an "opacity" attribute to use that value and anything without to 1.0
     fillStyleLayer.fillOpacity = [NSExpression mgl_expressionForConditional:@"opacity != nil"
-                                                             trueExpression:[NSExpression expressionForKeyPath:@"opacity"]
+                                                             trueExpression:[NSExpression expressionForKeyPath:@"opacity"] 
                                                            falseExpresssion:[NSExpression mgl_expressionForValue:@1.0]];
     [self.mapView.style addLayer:fillStyleLayer];
 }
author	Fabian Guerra <fabian.guerra@mapbox.com>	2018-03-09 18:27:05 -0500
committer	Fabian Guerra <fabian.guerra@mapbox.com>	2018-03-16 18:19:49 -0400
commit	51e8894352253b49b05bd5bd2cfc309f6b9bb20e (patch)
tree	cf8db10565145df11087d63578796405dad53cf4
parent	b37f422785b3e2cc66b9a3d6d43747381f6ac6f4 (diff)
download	qtlocation-mapboxgl-51e8894352253b49b05bd5bd2cfc309f6b9bb20e.tar.gz