Drastic Simplification of MPFunction subclass implementations

MathPad/MPFunction.h

@@ -11,12 +11,19 @@
 #import "MPParseError.h"
 #import "MPTerm.h"
 
+#define MPFunctionAccessorImplementation(Accessor, variableName) \
+- (void)set##Accessor:(MPExpression *)value \
+{ \
+    variableName.parent = nil; \
+    variableName = value; \
+    variableName.parent = self; \
+    [self didChangeChildAtIndex:[self indexOfChild:variableName]]; \
+}
+
 @class MPFunction, MPExpression, MPRangePath;
 
 @interface MPFunction : NSObject <NSCoding, NSCopying, MPExpressionElement>
 
-+ (NSString *)localizedFunctionName; // Override
-
 #pragma mark Creation Methods
 
 - (instancetype)init;
@@ -29,13 +36,14 @@
 - (MPExpression *)rootExpression;
 - (NSIndexPath *)indexPath;
 
-- (NSUInteger)numberOfChildren; // Override
+- (NSArray *)childrenAccessors; // Override
-- (MPExpression *)childAtIndex:(NSUInteger)index; // Override
-- (void)setChild:(MPExpression *)child
-         atIndex:(NSUInteger)index; // Override
 
-// May be overridden for performance improvements
+- (NSUInteger)numberOfChildren;
-- (NSArray *)children; // Indexes must equal the ones from the native methods
+- (MPExpression *)childAtIndex:(NSUInteger)index;
+- (void)setChild:(MPExpression *)child
+         atIndex:(NSUInteger)index;
+
+- (NSArray *)children; // Indexes must equal the ones from the other methods
 - (NSUInteger)indexOfChild:(MPExpression *)child;
 
 - (id)elementAtIndexPath:(NSIndexPath *)indexPath;
@@ -47,15 +55,14 @@
 #pragma mark Messages
 - (void)didChangeElementsInRangePath:(MPRangePath *)rangePath
                    replacementLength:(NSUInteger)replacementLength;
-- (void)didChangeChild:(MPExpression *)child;
 - (void)didChangeChildAtIndex:(NSUInteger)index;
 
 #pragma mark Working With Functions
 // - (BOOL)isEqualToFunction:(MPFunction *)aFunction; // Override
 
 - (NSString *)description; // Should be overridden
-- (NSUInteger)hash;// Override
+- (NSUInteger)hash;
 
-- (id)copyWithZone:(NSZone *)zone; // Override
+- (id)copyWithZone:(NSZone *)zone;
 
 @end

MathPad/MPFunction.m

@@ -24,6 +24,12 @@
 {
     self = [super init];
     if (self) {
+        for (NSString *key in self.childrenAccessors) {
+            MPExpression *emptyExpression = [[MPExpression alloc] init];
+            emptyExpression.parent = self;
+            [self setValue:emptyExpression
+                    forKey:key];
+        }
     }
     return self;
 }
@@ -42,17 +48,18 @@
 
 - (NSUInteger)numberOfChildren
 {
-    return 0;
+    return self.childrenAccessors.count;
 }
 
 - (MPExpression *)childAtIndex:(NSUInteger)index
 {
-    return nil;
+    return [self valueForKey:self.childrenAccessors[index]];
 }
 
 - (void)setChild:(MPExpression *)child
          atIndex:(NSUInteger)index
 {
+    [self setValue:child forKey:self.childrenAccessors[index]];
     [self didChangeChildAtIndex:index];
 }
 
@@ -86,12 +93,6 @@
     return [child elementAtIndexPath:[indexPath indexPathByRemovingFirstIndex]];
 }
 
-#pragma mark Evaluating Functions
-- (MPTerm *)parseWithError:(MPParseError *__autoreleasing *)error
-{
-    return nil;
-}
-
 #pragma mark Notifications
 - (void)didChangeElementsInRangePath:(MPRangePath *)rangePath
                    replacementLength:(NSUInteger)replacementLength
@@ -102,11 +103,6 @@
                             replacementLength:replacementLength];
 }
 
-- (void)didChangeChild:(MPExpression *)child
-{
-    [self didChangeChildAtIndex:[self indexOfChild:child]];
-}
-
 - (void)didChangeChildAtIndex:(NSUInteger)index
 {
     MPRangePath *path = [[MPRangePath alloc] initWithRange:NSMakeRange(index, 1)];
@@ -142,13 +138,19 @@
 
 - (NSUInteger)hash
 {
+#warning Unimplemented Method
     return 0;
 }
 
 #pragma mark - NSCopying
 - (id)copyWithZone:(NSZone *)zone
 {
-    return [[MPFunction allocWithZone:zone] init];
+    id copy = [[self.class allocWithZone:zone] init];
+    for (NSString *key in self.childrenAccessors) {
+        MPExpression *child = [[self valueForKey:key] copy];
+        [copy setValue:child forKey:key];
+    }
+    return copy;
 }
 
 #pragma mark - NSCoding

MathPad/MPParenthesisFunction.m

@@ -12,49 +12,18 @@
 
 @implementation MPParenthesisFunction
 
-+ (NSString *)localizedFunctionName
+MPFunctionAccessorImplementation(Expression, _expression)
-{
-    return NSLocalizedString(@"Parenthesis", @"Name of Parenthesis Function");
-}
 
-- (instancetype)init
+//- (void)setExpression:(MPExpression *)expression
-{
+//{
-    self = [super init];
+//    _expression.parent = nil;
-    if (self) {
+//    _expression = expression;
-        _expression = [[MPExpression alloc] init];
+//    _expression.parent = self;
-        _expression.parent = self;
+//}
-    }
-    return self;
-}
 
-- (void)setExpression:(MPExpression *)expression
+- (NSArray *)childrenAccessors
 {
-    _expression.parent = nil;
+    return @[@"expression"];
-    _expression = expression;
-    _expression.parent = self;
-}
-
-- (NSUInteger)numberOfChildren
-{
-    return 1;
-}
-
-- (MPExpression *)childAtIndex:(NSUInteger)index
-{
-    return index == 0 ? self.expression : nil;
-}
-
-- (void)setChild:(MPExpression *)child
-         atIndex:(NSUInteger)index
-{
-    if (index == 0) {
-        self.expression = child;
-    }
-}
-
-- (NSArray *)children
-{
-    return @[self.expression];
 }
 
 - (MPTerm *)parseWithError:(MPParseError *__autoreleasing *)error
@@ -64,27 +33,9 @@
                                        error:error];
 }
 
-- (NSDecimalNumber *)evaluateWithError:(MPParseError *__autoreleasing *)error
-{
-    return [self.expression evaluateWithError:error];
-}
-
 - (NSString *)description
 {
     return [NSString stringWithFormat:@"(%@)", self.expression.description];
 }
 
-- (NSUInteger)hash
-{
-#warning Unimplemented Method
-    return [super hash] * self.expression.hash;
-}
-
-- (id)copyWithZone:(NSZone *)zone
-{
-    MPParenthesisFunction *copy = [[MPParenthesisFunction allocWithZone:zone] init];
-    copy.expression = self.expression.copy;
-    return copy;
-}
-
 @end

MathPad/MPPowerFunction.h

@@ -0,0 +1,17 @@
+//
+//  MPPowerFunction.h
+//  MathPad
+//
+//  Created by Kim Wittenburg on 30.09.14.
+//  Copyright (c) 2014 Kim Wittenburg. All rights reserved.
+//
+
+#import <MathKit/MathKit.h>
+
+@interface MPPowerFunction : MPFunction
+
+@property (nonatomic, strong) MPExpression *exponentExpression;
+
+@property (nonatomic, strong) MPTerm *baseTerm;
+
+@end

MathPad/MPPowerFunction.m

@@ -0,0 +1,40 @@
+//
+//  MPPowerFunction.m
+//  MathPad
+//
+//  Created by Kim Wittenburg on 30.09.14.
+//  Copyright (c) 2014 Kim Wittenburg. All rights reserved.
+//
+
+#import "MPPowerFunction.h"
+#import "MPExpressionEvaluator.h"
+
+@implementation MPPowerFunction
+
+MPFunctionAccessorImplementation(ExponentExpression, _exponentExpression)
+
+- (NSArray *)childrenAccessors
+{
+    return @[@"exponentExpression"];
+}
+
+- (MPTerm *)parseWithError:(MPParseError *__autoreleasing *)error
+{
+    MPTerm *exponentTerm = [self.exponentExpression.evaluator parseExpectingVariable:NO
+                                                                               error:error];
+    if (exponentTerm == nil) {
+        return nil;
+    }
+    
+    return [[MPTerm alloc] initWithBlock:^NSDecimalNumber *{
+        double power = pow([self.baseTerm evaluate].doubleValue, [exponentTerm evaluate].doubleValue);
+        return [[NSDecimalNumber alloc] initWithDouble:power];
+    }];
+}
+
+- (NSString *)description
+{
+    return [NSString stringWithFormat:@"^%@", self.exponentExpression.description];
+}
+
+@end

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
+MPFunctionAccessorImplementation(StartExpression, _startExpression)
-{
+MPFunctionAccessorImplementation(TargetExpression, _targetExpression)
-    return NSLocalizedString(@"Sum", @"Name of Sum Function");
+MPFunctionAccessorImplementation(SumExpression, _sumExpression)
-}
 
-#pragma mark Creation Methods
+- (NSArray *)childrenAccessors
-- (instancetype)init
 {
-    self = [super init];
+    return @[@"startExpression", @"targetExpression", @"sumExpression"];
-    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];
 }
 
 #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