[ios, macos] Add match expressions support.

mapbox · Mar 16, 2018 · 7c8614b · 7c8614b
1 parent 449c68e
commit 7c8614b
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Showing 2 changed files with 61 additions and 0 deletions.
diff --git a/platform/darwin/src/NSExpression+MGLAdditions.mm b/platform/darwin/src/NSExpression+MGLAdditions.mm
@@ -207,6 +207,12 @@ - (NSNumber *)mgl_number {
     return nil;
 }
 
+- (id)mgl_matchWithOptions:(NSDictionary<NSNumber *, id> *)stops default:(id)minimum {
+    [NSException raise:NSInvalidArgumentException
+                format:@"Match expressions lack underlying Objective-C implementations."];
+    return nil;
+}
+
 @end
 
 @implementation NSNumber (MGLExpressionAdditions)
@@ -225,6 +231,12 @@ - (id)mgl_stepWithMinimum:(id)minimum stops:(NSDictionary<NSNumber *, id> *)stop
     return nil;
 }
 
+- (id)mgl_matchWithOptions:(NSDictionary<NSNumber *, id> *)stops default:(id)minimum {
+    [NSException raise:NSInvalidArgumentException
+                format:@"Match expressions lack underlying Objective-C implementations."];
+    return nil;
+}
+
 - (NSNumber *)mgl_number {
     return self;
 }
@@ -475,6 +487,26 @@ + (instancetype)mgl_expressionWithJSONObject:(id)object {
                 falseExpression = [NSExpression mgl_expressionWithJSONObject:argumentObjects[2]];
             }
             return [NSExpression expressionForConditional:conditional trueExpression:trueExpression falseExpression:falseExpression];
+        } else if ([op isEqualToString:@"match"]) {
+            NSExpression *operand = [NSExpression mgl_expressionWithJSONObject:argumentObjects[0]];
+            NSArray *matchOptions = [argumentObjects subarrayWithRange:NSMakeRange(1, argumentObjects.count - 1)];
+            NSExpression *defaultOption;
+            if (matchOptions.count % 2) {
+                defaultOption = [NSExpression mgl_expressionWithJSONObject:matchOptions.lastObject];
+                matchOptions = [matchOptions subarrayWithRange:NSMakeRange(0, matchOptions.count - 1)];
+            }
+            NSMutableArray *optionsArray = [NSMutableArray array];
+            NSEnumerator *optionsEnumerator = matchOptions.objectEnumerator;
+            while (NSNumber *key = optionsEnumerator.nextObject) {
+                NSMutableDictionary *option = [NSMutableDictionary dictionaryWithCapacity:1];
+                NSExpression *valueExpression = optionsEnumerator.nextObject;
+                option[key] = [NSExpression mgl_expressionWithJSONObject:valueExpression];
+                [optionsArray addObject:option];
+            }
+            NSExpression *optionsExpression = [NSExpression expressionForConstantValue:optionsArray];
+            return [NSExpression expressionForFunction:operand
+                                          selectorName:@"mgl_matchWithOptions:default:"
+                                             arguments:@[optionsExpression, defaultOption]];
         } else {
             [NSException raise:NSInvalidArgumentException
                         format:@"Expression operator %@ not yet implemented.", op];
@@ -666,6 +698,18 @@ - (id)mgl_jsonExpressionObject {
                 }];
                 [expressionObject addObject:self.operand.mgl_jsonExpressionObject];
                 return expressionObject;
+            } else if ([function isEqualToString:@"mgl_matchWithOptions:default:"]) {
+                NSMutableArray *expressionObject = [NSMutableArray arrayWithObjects:@"match", self.operand.mgl_jsonExpressionObject, nil];
+                NSArray *optionsArray = self.arguments[0].constantValue;
+                for (NSDictionary<id, NSExpression*> *options in optionsArray) {
+                    for (NSNumber *key in options.allKeys) {
+                        [expressionObject addObject:key];
+                        [expressionObject addObject:[options[key] mgl_jsonExpressionObject]];
+                    }
+                }
+
+                [expressionObject addObject:[self.arguments[1] mgl_jsonExpressionObject]];
+                return expressionObject;
             } else if ([function isEqualToString:@"median:"] ||
                        [function isEqualToString:@"mode:"] ||
                        [function isEqualToString:@"stddev:"] ||

diff --git a/platform/darwin/test/MGLExpressionTests.mm b/platform/darwin/test/MGLExpressionTests.mm
@@ -572,6 +572,23 @@ - (void)testInterpolationExpressionObject {
     }
 }
 
+- (void)testMatchExpressionObject {
+    {
+        NSArray *options = @[@{@1 : MGLConstantExpression(@"one")}, @{@0 : MGLConstantExpression(@"zero")}];
+        NSExpression *expression = [NSExpression expressionWithFormat:@"FUNCTION(2 - 1, 'mgl_matchWithOptions:default:', %@, 'default')", options];
+        NSArray *jsonExpression =  @[@"match", @[@"-", @2, @1], @1, @"one", @0, @"zero", @"default"];
+        XCTAssertEqualObjects(expression.mgl_jsonExpressionObject, jsonExpression);
+        XCTAssertEqualObjects( [NSExpression mgl_expressionWithJSONObject:jsonExpression], expression);
+    }
+    {
+        NSArray *options = @[@{@1 : MGLConstantExpression(@"one")}];
+        NSExpression *expression = [NSExpression expressionWithFormat:@"FUNCTION(2 * 1, 'mgl_matchWithOptions:default:', %@, 'default')", options];
+        NSArray *jsonExpression =  @[@"match", @[@"*", @2, @1], @1, @"one", @"default"];
+        XCTAssertEqualObjects(expression.mgl_jsonExpressionObject, jsonExpression);
+        XCTAssertEqualObjects( [NSExpression mgl_expressionWithJSONObject:jsonExpression], expression);
+    }
+}
+
 - (void)testConditionalExpressionObject {
     // FIXME: This test crashes because iOS 8 doesn't have `+[NSExpression expressionForConditional:trueExpression:falseExpression:]`.
     // https://github.com/mapbox/mapbox-gl-native/issues/11007