3 files changed, 37 insertions, 44 deletions

diff --git a/platform/darwin/src/MGLAttributedExpression.h b/platform/darwin/src/MGLAttributedExpression.h
index 32f1a96dae..ea298c7a44 100644
--- a/platform/darwin/src/MGLAttributedExpression.h
+++ b/platform/darwin/src/MGLAttributedExpression.h
@@ -2,10 +2,16 @@
 
 NS_ASSUME_NONNULL_BEGIN
 
-typedef NSString * MGLAttributedExpressionKey NS_EXTENSIBLE_STRING_ENUM;
+/** Options for `MGLAttributedExpression.attributes`. */
+typedef NSString * MGLAttributedExpressionKey NS_TYPED_ENUM;
 
+/** The font name string array expression used to format the text. */
 FOUNDATION_EXTERN MGL_EXPORT MGLAttributedExpressionKey const MGLFontNamesAttribute;
-FOUNDATION_EXTERN MGL_EXPORT MGLAttributedExpressionKey const MGLFontSizeAttribute;
+
+/** The font scale number expression relative to `MGLSymbolStyleLayer.textFontSize` used to format the text. */
+FOUNDATION_EXTERN MGL_EXPORT MGLAttributedExpressionKey const MGLFontScaleAttribute;
+
+/** The font color expression used to format the text. */
 FOUNDATION_EXTERN MGL_EXPORT MGLAttributedExpressionKey const MGLFontColorAttribute;
 
 /**
@@ -16,10 +22,10 @@ FOUNDATION_EXTERN MGL_EXPORT MGLAttributedExpressionKey const MGLFontColorAttrib
  ```swift
  let redColor = UIColor.red
  let expression = NSExpression(forConstantValue: "Foo")
- let attributes: Dictionary<MGLAttributedExpressionKey, Any> = [.fontNamesAttribute : ["DIN Offc Pro Italic",
-                                                                                       "Arial Unicode MS Regular"],
-                                                                .fontSizeAttribute: 1.2,
-                                                                .fontColorAttribute: redColor]
+ let attributes: [MGLAttributedExpressionKey: NSExpression] = [.fontNamesAttribute : NSExpression(forConstantValue: ["DIN Offc Pro Italic",
+                                                                                                                     "Arial Unicode MS Regular"]),
+                                                               .fontScaleAttribute: NSExpression(forConstantValue: 1.2),
+                                                               .fontColorAttribute: NSExpression(forConstantValue: redColor)]
  let attributedExpression = MGLAttributedExpression(expression, attributes:attributes)
  ```
  
@@ -37,22 +43,22 @@ MGL_EXPORT
  The formatting attributes dictionary.
  Key | Value Type
  --- | ---
- `MGLFontNamesAttribute` | `NSArray<NSString *>*`
- `MGLFontSizeAttribute` | `NSNumber`
- `MGLFontColorAttribute` | `UIColor`
+ `MGLFontNamesAttribute` | An `NSExpression` evaluating to an `NSString` array.
+ `MGLFontScaleAttribute` | An `NSExpression` evaluating to an `NSNumber` value.
+ `MGLFontColorAttribute` | An `NSExpression` evaluating to an `UIColor`.
 
  */
-@property (strong, nonatomic, readonly) NSDictionary<MGLAttributedExpressionKey, id> *attributes;
+@property (strong, nonatomic, readonly) NSDictionary<MGLAttributedExpressionKey, NSExpression *> *attributes;
 #else
 /**
  The formatting attributes dictionary.
  Key | Value Type
  --- | ---
- `MGLFontNamesAttribute` | `NSArray<NSString *>*`
- `MGLFontSizeAttribute` | `NSNumber`
- `MGLFontColorAttribute` | `NSColor`
+ `MGLFontNamesAttribute` | An `NSExpression` evaluating to an `NSString` array.
+ `MGLFontScaleAttribute` | An `NSExpression` evaluating to an `NSNumber` value.
+ `MGLFontColorAttribute` | An `NSExpression` evaluating to an `NSColor` on macos.
  */
-@property (strong, nonatomic, readonly) NSDictionary<MGLAttributedExpressionKey, id> *attributes;
+@property (strong, nonatomic, readonly) NSDictionary<MGLAttributedExpressionKey, NSExpression *> *attributes;
 #endif
 
 
@@ -64,17 +70,17 @@ MGL_EXPORT
 /** 
  Returns an `MGLAttributedExpression` object initialized with an expression and text format attributes.
  */
-- (instancetype)initWithExpression:(NSExpression *)expression attributes:(nonnull NSDictionary <MGLAttributedExpressionKey, id> *)attrs;
+- (instancetype)initWithExpression:(NSExpression *)expression attributes:(nonnull NSDictionary <MGLAttributedExpressionKey, NSExpression *> *)attrs;
 
 /**
  Creates an `MGLAttributedExpression` object initialized with an expression and the format attributes for font names and font size.
  */
-+ (instancetype)attributedExpression:(NSExpression *)expression fontNames:(nullable NSArray<NSString*> *)fontNames fontSize:(nullable NSNumber *)fontSize;
++ (instancetype)attributedExpression:(NSExpression *)expression fontNames:(nullable NSArray<NSString*> *)fontNames fontScale:(nullable NSNumber *)fontScale;
 
 /**
  Creates an `MGLAttributedExpression` object initialized with an expression and the format attributes dictionary.
  */
-+ (instancetype)attributedExpression:(NSExpression *)expression attributes:(nonnull NSDictionary <MGLAttributedExpressionKey, id> *)attrs;
++ (instancetype)attributedExpression:(NSExpression *)expression attributes:(nonnull NSDictionary <MGLAttributedExpressionKey, NSExpression *> *)attrs;
 
 @end
 
diff --git a/platform/darwin/src/MGLAttributedExpression.m b/platform/darwin/src/MGLAttributedExpression.m
index 000701f7cf..a34480a957 100644
--- a/platform/darwin/src/MGLAttributedExpression.m
+++ b/platform/darwin/src/MGLAttributedExpression.m
@@ -2,7 +2,7 @@
 #import "MGLLoggingConfiguration_Private.h"
 
 const MGLAttributedExpressionKey MGLFontNamesAttribute = @"text-font";
-const MGLAttributedExpressionKey MGLFontSizeAttribute = @"font-scale";
+const MGLAttributedExpressionKey MGLFontScaleAttribute = @"font-scale";
 const MGLAttributedExpressionKey MGLFontColorAttribute = @"text-color";
 
 @implementation MGLAttributedExpression
@@ -12,24 +12,24 @@ const MGLAttributedExpressionKey MGLFontColorAttribute = @"text-color";
     return self;
 }
 
-+ (instancetype)attributedExpression:(NSExpression *)expression fontNames:(nullable NSArray<NSString *> *)fontNames fontSize:(nullable NSNumber *)fontSize {
++ (instancetype)attributedExpression:(NSExpression *)expression fontNames:(nullable NSArray<NSString *> *)fontNames fontScale:(nullable NSNumber *)fontScale {
     MGLAttributedExpression *attributedExpression;
     
     NSMutableDictionary *attrs = [NSMutableDictionary dictionary];
     
     if (fontNames && fontNames.count > 0) {
-        attrs[MGLFontNamesAttribute] = fontNames;
+        attrs[MGLFontNamesAttribute] = [NSExpression expressionForConstantValue:fontNames];
     }
     
-    if (fontSize) {
-        attrs[MGLFontSizeAttribute] = fontSize;
+    if (fontScale) {
+        attrs[MGLFontScaleAttribute] = [NSExpression expressionForConstantValue:fontScale];
     }
     
     attributedExpression = [[self alloc] initWithExpression:expression attributes:attrs];
     return attributedExpression;
 }
 
-+ (instancetype)attributedExpression:(NSExpression *)expression attributes:(nonnull NSDictionary<MGLAttributedExpressionKey,id> *)attrs {
++ (instancetype)attributedExpression:(NSExpression *)expression attributes:(nonnull NSDictionary<MGLAttributedExpressionKey, NSExpression *> *)attrs {
     MGLAttributedExpression *attributedExpression;
     
     attributedExpression = [[self alloc] initWithExpression:expression attributes:attrs];
@@ -37,7 +37,7 @@ const MGLAttributedExpressionKey MGLFontColorAttribute = @"text-color";
     return attributedExpression;
 }
 
-- (instancetype)initWithExpression:(NSExpression *)expression attributes:(nonnull NSDictionary<MGLAttributedExpressionKey,id> *)attrs {
+- (instancetype)initWithExpression:(NSExpression *)expression attributes:(nonnull NSDictionary<MGLAttributedExpressionKey, NSExpression *> *)attrs {
     if (self = [super init])
     {
         MGLLogInfo(@"Starting %@ initialization.", NSStringFromClass([self class]));
diff --git a/platform/darwin/src/NSExpression+MGLAdditions.mm b/platform/darwin/src/NSExpression+MGLAdditions.mm
index b509c12172..4b1fdb818e 100644
--- a/platform/darwin/src/NSExpression+MGLAdditions.mm
+++ b/platform/darwin/src/NSExpression+MGLAdditions.mm
@@ -882,19 +882,8 @@ NSArray *MGLSubexpressionsWithJSONObjects(NSArray *objects) {
                     attrs = [NSMutableDictionary dictionaryWithDictionary:argumentObjects[index + 1]];
                 }
                 
-                if (attrs.count) {
-                    if (NSArray *fontNames = MGL_OBJC_DYNAMIC_CAST(attrs[MGLFontNamesAttribute], NSArray)) {
-                        attrs[MGLFontNamesAttribute] = fontNames[1];
-                    }
-                    if (NSArray *colorArray = MGL_OBJC_DYNAMIC_CAST(attrs[MGLFontColorAttribute], NSArray)) {
-                        if ([colorArray[0] isEqualToString:@"rgb"] || [colorArray[0] isEqualToString:@"rgba"]) {
-                            NSArray *colorArguments = [colorArray subarrayWithRange:NSMakeRange(1, colorArray.count - 1)];
-                            NSArray *subexpressions = MGLSubexpressionsWithJSONObjects(colorArguments);
-                            MGLColor *color = [NSExpression mgl_colorWithRGBComponents:subexpressions];
-
-                            attrs[MGLFontColorAttribute] = color;
-                        }
-                    }
+                for (NSString *key in attrs.allKeys) {
+                    attrs[key] = [NSExpression expressionWithMGLJSONObject:attrs[key]];
                 }
                 MGLAttributedExpression *attributedExpression = [[MGLAttributedExpression alloc] initWithExpression:expression attributes:attrs];
 
@@ -1016,17 +1005,15 @@ NSArray *MGLSubexpressionsWithJSONObjects(NSArray *objects) {
             if ([constantValue isKindOfClass:[MGLAttributedExpression class]]) {
                 MGLAttributedExpression *attributedExpression = (MGLAttributedExpression *)constantValue;
                 id jsonObject = attributedExpression.expression.mgl_jsonExpressionObject;
-                NSMutableDictionary *attributedDictionary = [NSMutableDictionary dictionary];
+                NSMutableDictionary<MGLAttributedExpressionKey, NSExpression *> *attributedDictionary = [NSMutableDictionary dictionary];
                 
                 if (attributedExpression.attributes) {
                     attributedDictionary = [NSMutableDictionary dictionaryWithDictionary:attributedExpression.attributes];
-                    if (attributedDictionary[MGLFontNamesAttribute]) {
-                        attributedDictionary[MGLFontNamesAttribute] = @[@"literal", attributedDictionary[MGLFontNamesAttribute]];
-                    }
-                    if (attributedDictionary[MGLFontColorAttribute] && [attributedDictionary[MGLFontColorAttribute] isKindOfClass:[MGLColor class]]) {
-                        MGLColor *color = attributedDictionary[MGLFontColorAttribute];
-                        attributedDictionary[MGLFontColorAttribute] = color.mgl_jsonExpressionObject;
+                    
+                    for (NSString *key in attributedExpression.attributes.allKeys) {
+                        attributedDictionary[key] = attributedExpression.attributes[key].mgl_jsonExpressionObject;
                     }
+                    
                 } 
                 return @[jsonObject, attributedDictionary];
             }