91 lines
3.2 KiB
Objective-C
91 lines
3.2 KiB
Objective-C
//
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// MPSumFunction.m
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// MathPad
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//
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// Created by Kim Wittenburg on 22.04.14.
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// Copyright (c) 2014 Kim Wittenburg. All rights reserved.
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//
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#import "MPSumFunction.h"
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#import "MPExpression.h"
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#import "MPExpressionEvaluator.h"
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#import "MPEvaluationContext.h"
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// TODO: Use this macro elsewhere
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#define ReturnIfNil(test) if(test == nil) return nil
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@implementation MPSumFunction
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MPFunctionAccessorImplementation(StartExpression, _startExpression)
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MPFunctionAccessorImplementation(TargetExpression, _targetExpression)
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MPFunctionAccessorImplementation(SumExpression, _sumExpression)
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- (NSArray *)childrenAccessors
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{
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return @[@"startExpression", @"targetExpression", @"sumExpression"];
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}
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#pragma mark Evaluating Functions
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- (MPTerm *)parseWithError:(MPParseError *__autoreleasing *)error
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{
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MPExpressionEvaluator *startEvaluator = [[MPExpressionEvaluator alloc] initWithExpression:self.startExpression];
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MPTerm *start = [startEvaluator parseExpectingVariable:YES
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error:error];
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ReturnIfNil(start);
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MPExpressionEvaluator *targetEvaluator = [[MPExpressionEvaluator alloc] initWithExpression:self.targetExpression];
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MPTerm *target = [targetEvaluator parseExpectingVariable:NO
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error:error];
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ReturnIfNil(target);
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NSString *variable = startEvaluator.definedVariable.copy;
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[[MPEvaluationContext sharedContext] push];
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[[MPEvaluationContext sharedContext] defineVariable:variable withValue:[NSNull null]];
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MPExpressionEvaluator *sumEvaluator = [[MPExpressionEvaluator alloc] initWithExpression:self.sumExpression];
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MPTerm *sum = [sumEvaluator parseExpectingVariable:NO
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error:error];
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ReturnIfNil(sum);
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[[MPEvaluationContext sharedContext] pop];
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return [[MPTerm alloc] initWithBlock:^NSDecimalNumber *{
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[[MPEvaluationContext sharedContext] push];
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NSDecimalNumber *value = [NSDecimalNumber zero];
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NSDecimalNumber *startValue = [start evaluate];
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NSDecimalNumber *targetValue = [target evaluate];
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for (NSDecimalNumber *iterator = startValue;
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[iterator compare:targetValue] <= 0 ;
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iterator = [iterator decimalNumberByAdding:[[NSDecimalNumber alloc] initWithInteger:1]]) {
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[[MPEvaluationContext sharedContext] defineVariable:variable withValue:iterator];
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value = [value decimalNumberByAdding:[sum evaluate]];
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}
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[[MPEvaluationContext sharedContext] pop];
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return value;
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}];
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}
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#pragma mark Working With Functions
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/*
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- (BOOL)isEqualToFunction:(MPFunction *)aFunction
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{
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if (![aFunction isKindOfClass:[MPSumFunction class]]) {
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return NO;
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}
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MPSumFunction *sumFunction = (MPSumFunction *)aFunction;
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if (![self.startExpression isEqualToExpression:sumFunction.startExpression]) {
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return NO;
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}
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if (![self.targetExpression isEqualToExpression:sumFunction.targetExpression]) {
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return NO;
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}
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return [self.sumExpression isEqualToExpression:sumFunction.sumExpression];
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}*/
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- (NSString *)description
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{
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return [NSString stringWithFormat:@"Sum(From: %@; To: %@; Using: %@)", self.startExpression, self.targetExpression, self.sumExpression];
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}
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@end
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