[ios, macos] Add to-rgba expression operator. (#11725)

* [ios, macos] Add expression support to to-rgba operator.

* [ios, macos] Update style docs.

* [ios, macos] Refactored to-rgba to to-color.

* [ios, macos] Add support for to-rgba expression operator.

* [ios, macos] Add multiple parameters support to to-color operand.

* [ios, macos] Enable to-rgba operator for MGLColor or key path expressions.

* [ios, macos] Update predicates and expressions guide to reflect cast changes.

* [ios, macos] Update changelogs.

* [ios, macos] Clarify color casting usage.

1 files changed, 32 insertions, 0 deletions

diff --git a/platform/darwin/test/MGLExpressionTests.mm b/platform/darwin/test/MGLExpressionTests.mm
index 186cae609d..4ed1f61eb1 100644
--- a/platform/darwin/test/MGLExpressionTests.mm
+++ b/platform/darwin/test/MGLExpressionTests.mm
@@ -668,6 +668,38 @@ using namespace std::string_literals;
         XCTAssertEqualObjects([compatibilityExpression expressionValueWithObject:@{@"number": @1.5} context:nil], @"1.5");
         XCTAssertEqualObjects([NSExpression expressionWithMGLJSONObject:jsonExpression], expression);
     }
+    {
+#if TARGET_OS_IPHONE
+        NSExpression *expression = [NSExpression expressionWithFormat:@"CAST(x, 'UIColor')"];
+#else
+        NSExpression *expression = [NSExpression expressionWithFormat:@"CAST(x, 'NSColor')"];
+#endif
+        
+        NSArray *jsonExpression = @[@"to-color", @[@"get", @"x"]];
+        XCTAssertEqualObjects(expression.mgl_jsonExpressionObject, jsonExpression);
+        XCTAssertEqualObjects([NSExpression expressionWithMGLJSONObject:jsonExpression], expression);
+    }
+    {
+        NSExpression *expression = [NSExpression expressionWithFormat:@"MGL_FUNCTION('to-color', x, y, z)"];
+        NSArray *jsonExpression = @[@"to-color", @[@"get", @"x"], @[@"get", @"y"], @[@"get", @"z"]];
+        XCTAssertEqualObjects(expression.mgl_jsonExpressionObject, jsonExpression);
+    }
+    {
+        NSExpression *expression = [NSExpression expressionWithFormat:@"CAST(noindex(x), 'NSArray')"];
+        NSArray *jsonExpression = @[@"to-rgba", @[@"get", @"x"]];
+        XCTAssertEqualObjects(expression.mgl_jsonExpressionObject, jsonExpression);
+        XCTAssertEqualObjects([NSExpression expressionWithMGLJSONObject:jsonExpression], expression);
+    }
+    {
+        NSExpression *expression = [NSExpression expressionWithFormat:@"CAST(noindex(%@), 'NSArray')", MGLConstantExpression(MGLColor.blueColor)];
+        NSArray *jsonExpression = @[@"to-rgba", @[@"rgb", @0, @0, @255]];
+        XCTAssertEqualObjects(expression.mgl_jsonExpressionObject, jsonExpression);
+        XCTAssertEqualObjects([NSExpression expressionWithMGLJSONObject:jsonExpression], expression);
+    }
+    {
+        NSExpression *expression = [NSExpression expressionWithFormat:@"CAST(noindex('x'), 'NSArray')"];
+        XCTAssertThrowsSpecificNamed(expression.mgl_jsonExpressionObject, NSException, NSInvalidArgumentException);
+    }
 }
 
 - (void)testInterpolationExpressionObject {