159 lines
4.0 KiB
Objective-C
159 lines
4.0 KiB
Objective-C
//
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// MPExpressionTree.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 "MPExpressionTree.h"
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@implementation MPExpressionTree {
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NSRange _variableDefinitionRange;
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NSMutableArray *_summands;
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NSRange _range;
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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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_summands = [[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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MPTokenStreamRecordCurrentLocation(tokenStream);
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[tokenStream beginIgnoringWhitespaceTokens];
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_variableDefinitionRange = NSMakeRange(NSNotFound, 0);
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self.definedVariable = nil;
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if (tokenStream.currentToken.tokenType == MPVariableToken) {
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if (tokenStream.peekNextToken.tokenType == MPEqualsToken) {
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self.definedVariable = tokenStream.currentToken.stringValue;
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NSRange variableRange = tokenStream.currentToken.range;
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[tokenStream currentTokenConsumed];
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NSRange equalsRange = tokenStream.currentToken.range;
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[tokenStream currentTokenConsumed];
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_variableDefinitionRange = NSUnionRange(variableRange, equalsRange);
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}
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}
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while ([tokenStream hasMoreTokens]) {
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[_summands addObject:[[MPSummand alloc] initWithTokenStream:tokenStream]];
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}
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[tokenStream endIgnoringOrAcceptingWhitespaceTokens];
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_range = MPTokenStreamRecordedRange(tokenStream);
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}
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return self;
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}
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- (NSRange)range
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{
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return _range;
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}
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- (BOOL)validate:(MPParseError *__autoreleasing *)error
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{
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return [self validateExpectingVariableDefinition:NO
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error:error];
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}
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- (BOOL)validateExpectingVariableDefinition:(BOOL)flag
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error:(MPParseError *__autoreleasing *)error
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{
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if (flag) {
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if (!self.definedVariable) {
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if (error) {
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*error = MPParseError(NSMakeRange(self.range.location, 0), @"Expected Variable Definition.");
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}
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return NO;
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}
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} else {
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if (self.definedVariable) {
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if (error) {
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*error = MPParseError(_variableDefinitionRange, @"Unexpected Variable Definition");
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}
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return NO;
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}
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}
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if (_summands.count == 0) {
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if (error) {
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*error = MPParseError(self.range, @"Empty Expression.");
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}
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return NO;
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}
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for (MPSummand *summand in _summands) {
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if (![summand 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 zero];
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for (MPSummand *summand in _summands) {
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NSDecimalNumber *currentValue = [summand 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 decimalNumberByAdding:currentValue];
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}
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return value;
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}
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- (NSArray *)expressionElements
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{
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NSMutableArray *elements = [[NSMutableArray alloc] init];
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if (self.definedVariable) {
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[elements addObject:[NSString stringWithFormat:@"%@=", self.definedVariable]];
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}
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for (MPSummand *summand in _summands) {
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[elements addObjectsFromArray:summand.expressionElements];
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}
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return elements;
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}
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- (NSArray *)summands
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{
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return _summands;
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}
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- (void)appendSummand:(MPSummand *)summand
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{
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[_summands addObject:summand];
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}
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- (void)insertSummand:(MPSummand *)summand
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atIndex:(NSUInteger)index
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{
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[_summands insertObject:summand
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atIndex:index];
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}
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- (void)removeSummand:(MPSummand *)summand
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{
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[_summands removeObject:summand];
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}
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- (void)removeSummandAtIndex:(NSUInteger)index
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{
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[_summands removeObjectAtIndex:index];
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}
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- (MPSummand *)summandAtIndex:(NSUInteger)index
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{
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return [_summands objectAtIndex:index];
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}
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@end
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