Implemented the Sum Function

MathPad/MPSumFunction.m

@@ -0,0 +1,120 @@
+//
+//  MPSumFunction.m
+//  MathPad
+//
+//  Created by Kim Wittenburg on 22.04.14.
+//  Copyright (c) 2014 Kim Wittenburg. All rights reserved.
+//
+
+#import "MPSumFunction.h"
+#import "MPExpression.h"
+
+@implementation MPSumFunction
+
+#pragma mark Creation Methods
+
+- (instancetype)init
+{
+    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 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;
+    }
+}
+
+- (NSArray *)children
+{
+    return @[self.startExpression, self.targetExpression, self.sumExpression];
+}
+
+- (void)setChild:(MPExpression *)child
+         atIndex:(NSUInteger)index
+{
+    switch (index) {
+            // TODO: Copy child?
+        case 0:
+            self.startExpression.parent = nil;
+            self.startExpression = child;
+            break;
+        case 1:
+            self.targetExpression.parent = nil;
+            self.targetExpression = child;
+            break;
+        case 2:
+            self.sumExpression.parent = nil;
+            self.sumExpression = child;
+            break;
+        default:
+            return;
+    }
+    child.parent = self;
+}
+
+#pragma mark Evaluating Functions
+
+- (double)doubleValue
+{
+#warning Implementation
+    return 0;
+}
+
+#pragma mark Working With Functions
+
+- (BOOL)isEqualToFunction:(MPFunction *)aFunction
+{
+    if (![aFunction isKindOfClass:[MPSumFunction class]]) {
+        return NO;
+    }
+    MPSumFunction *sumFunction = (MPSumFunction *)aFunction;
+    if (![self.startExpression isEqualToExpression:sumFunction.startExpression]) {
+        return NO;
+    }
+    if (![self.targetExpression isEqualToExpression:sumFunction.targetExpression]) {
+        return NO;
+    }
+    return [self.sumExpression isEqualToExpression:sumFunction.sumExpression];
+}
+
+- (NSString *)description
+{
+    return [NSString stringWithFormat:@"Sum(From: %@; To: %@; Using: %@)", self.startExpression, self.targetExpression, self.sumExpression];
+}
+
+#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