Drastic Simplification of MPFunction subclass implementations

MathPad/MPSumFunction.m

@@ -12,98 +12,18 @@
 #import "MPExpressionEvaluator.h"
 #import "MPEvaluationContext.h"
 
+// TODO: Use this macro elsewhere
 #define ReturnIfNil(test) if(test == nil) return nil
 
 @implementation MPSumFunction
 
-+ (NSString *)localizedFunctionName
-{
-    return NSLocalizedString(@"Sum", @"Name of Sum Function");
-}
+MPFunctionAccessorImplementation(StartExpression, _startExpression)
+MPFunctionAccessorImplementation(TargetExpression, _targetExpression)
+MPFunctionAccessorImplementation(SumExpression, _sumExpression)
 
-#pragma mark Creation Methods
-- (instancetype)init
+- (NSArray *)childrenAccessors
 {
-    self = [super init];
-    if (self) {
-        _startExpression = [[MPExpression alloc] init];
-        _startExpression.parent = self;
-        _targetExpression = [[MPExpression alloc] init];
-        _targetExpression.parent = self;
-        _sumExpression = [[MPExpression alloc] init];
-        _sumExpression.parent = self;
-    }
-    return self;
-}
-
-#pragma mark Properties
-- (void)setStartExpression:(MPExpression *)startExpression
-{
-    _startExpression.parent = nil;
-    _startExpression = startExpression;
-    _startExpression.parent = self;
-    [self didChangeChildAtIndex:0];
-}
-
-- (void)setTargetExpression:(MPExpression *)targetExpression
-{
-    _targetExpression.parent = nil;
-    _targetExpression = targetExpression;
-    _targetExpression.parent = self;
-    [self didChangeChildAtIndex:1];
-}
-
-- (void)setSumExpression:(MPExpression *)sumExpression
-{
-    _sumExpression.parent = nil;
-    _sumExpression = sumExpression;
-    _sumExpression.parent = self;
-    [self didChangeChildAtIndex:2];
-}
-
-#pragma mark Working With the Expression Tree
-- (NSUInteger)numberOfChildren
-{
-    return 3;
-}
-
-- (MPExpression *)childAtIndex:(NSUInteger)index
-{
-    switch (index) {
-        case 0:
-            return self.startExpression;
-        case 1:
-            return self.targetExpression;
-        case 2:
-            return self.sumExpression;
-        default:
-            return nil;
-    }
-}
-
-- (void)setChild:(MPExpression *)child
-         atIndex:(NSUInteger)index
-{
-    switch (index) {
-            // TODO: Copy child?
-        case 0:
-            self.startExpression = child;
-            break;
-        case 1:
-            self.targetExpression = child;
-            break;
-        case 2:
-            self.sumExpression = child;
-            break;
-        default:
-            return;
-    }
-    [self didChangeChildAtIndex:index];
-}
-
-- (NSArray *)children
-{
-    return @[self.startExpression, self.targetExpression, self.sumExpression];
+    return @[@"startExpression", @"targetExpression", @"sumExpression"];
 }
 
 #pragma mark Evaluating Functions
@@ -167,20 +87,4 @@
     return [NSString stringWithFormat:@"Sum(From: %@; To: %@; Using: %@)", self.startExpression, self.targetExpression, self.sumExpression];
 }
 
-- (NSUInteger)hash
-{
-#warning Unimplemented Method
-    return [super hash];
-}
-
-#pragma mark - NSCopying
-- (id)copyWithZone:(NSZone *)zone
-{
-    MPSumFunction *copy = [[MPSumFunction allocWithZone:zone] init];
-    copy.startExpression = [self.startExpression copy];
-    copy.targetExpression = [self.targetExpression copy];
-    copy.sumExpression = [self.sumExpression copy];
-    return copy;
-}
-
 @end