[ios, macos] Change the format for case expressions to a flat structure. (#11450)

* [ios, macos] Change the format for case expressions to a flat structure.

* [ios, macos] Add support for multiple branches case expression.

* [ios, macos] Add multiple branch tests to case expressions.

* [ios, macos] Case operator now has iOS 8 support.

1 files changed, 25 insertions, 0 deletions

diff --git a/platform/darwin/src/NSPredicate+MGLAdditions.mm b/platform/darwin/src/NSPredicate+MGLAdditions.mm
index 63c8307803..2d5b646ff2 100644
--- a/platform/darwin/src/NSPredicate+MGLAdditions.mm
+++ b/platform/darwin/src/NSPredicate+MGLAdditions.mm
@@ -324,4 +324,29 @@ NSArray *MGLSubpredicatesWithJSONObjects(NSArray *objects) {
     return nil;
 }
 
+- (id)mgl_case:(id)firstValue, ... {
+
+    if ([self evaluateWithObject:nil]) {
+        return firstValue;
+    }
+    
+    id eachExpression;
+    va_list argumentList;
+    va_start(argumentList, firstValue);
+    
+    while ((eachExpression = va_arg(argumentList, id))) {
+        if ([eachExpression isKindOfClass:[NSComparisonPredicate class]]) {
+            id valueExpression = va_arg(argumentList, id);
+            if ([eachExpression evaluateWithObject:nil]) {
+                return valueExpression;
+            }
+        } else {
+            return eachExpression;
+        }
+    }
+    va_end(argumentList);
+    
+    return nil;
+}
+
 @end