93 lines
2.4 KiB
Objective-C
93 lines
2.4 KiB
Objective-C
//
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// MPProduct.m
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// MathPad
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//
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// Created by Kim Wittenburg on 09.10.14.
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// Copyright (c) 2014 Kim Wittenburg. All rights reserved.
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//
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#import "MPProduct.h"
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#import "MPValueGroup.h"
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@implementation MPProduct {
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NSMutableArray *_factors;
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}
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- (id)init
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{
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self = [super init];
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if (self) {
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_factors = [[NSMutableArray alloc] init];
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}
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return self;
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}
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- (instancetype)initWithTokenStream:(MPTokenStream *)tokenStream
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{
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self = [self init];
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if (self) {
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[tokenStream beginIgnoringWhitespaceTokens];
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while (tokenStream.currentToken.tokenType != MPOperatorListToken && tokenStream.currentToken.tokenType != MPEOFToken) {
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[_factors addObject:[[MPFactor alloc] initWithTokenStream:tokenStream]];
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}
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[tokenStream endIgnoringOrAcceptingWhitespaceTokens];
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}
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return self;
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}
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- (NSArray *)factors
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{
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return _factors;
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}
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- (BOOL)validate:(NSError *__autoreleasing *)error
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{
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if (_factors.count == 0) {
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if (error) {
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*error = MPParseError(5,
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NSLocalizedString(@"Expected A Value.", @"Error message. Displayed when a value was expected in an expression but none was found."),
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nil);
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}
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return NO;
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}
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MPFactor *factor = _factors[0];
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if (factor.hasMultiplicationSymbol) {
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if (error) {
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*error = MPParseError(6,
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NSLocalizedString(@"Unexpected Symbol.", @"Error message. Displayed when or inappropriate symbol was encountered during parsing."),
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nil);
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}
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return NO;
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}
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if (![factor.value validate:error]) {
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return NO;
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}
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for (NSUInteger index = 1; index < _factors.count; index++) {
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factor = _factors[index];
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if (![factor validate:error]) {
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return NO;
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}
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}
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return YES;
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}
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- (NSDecimalNumber *)evaluate
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{
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NSDecimalNumber *value = [NSDecimalNumber one];
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for (MPFactor *factor in _factors) {
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NSDecimalNumber *currentValue = [factor evaluate];
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if ([currentValue isEqualToNumber:[NSDecimalNumber notANumber]]) {
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value = currentValue;
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break;
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}
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value = [value decimalNumberByMultiplyingBy:currentValue];
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if ([value compare:@(0)] == NSOrderedSame) {
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break;
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}
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}
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return value;
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}
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@end
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