71 lines
1.6 KiB
Objective-C
71 lines
1.6 KiB
Objective-C
//
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// MPVariable.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 "MPVariable.h"
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#import "MPTokenStream.h"
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#import "MPToken.h"
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#import "MPExpression.h"
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#import "MPEvaluationContext.h"
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@implementation MPVariable {
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NSRange _range;
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}
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- (instancetype)init
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{
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self = [super init];
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if (self) {
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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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MPToken *token = tokenStream.currentToken;
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if (token.tokenType == MPVariableToken) {
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_variableName = token.stringValue;
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_range = token.range;
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} else {
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@throw [NSException exceptionWithName:NSInternalInconsistencyException reason:@"Expected Variable" userInfo:nil];
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}
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[tokenStream currentTokenConsumed];
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[tokenStream endIgnoringOrAcceptingWhitespaceTokens];
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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:(NSError *__autoreleasing *)error
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{
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if (![[MPEvaluationContext sharedContext] isVariableDefined:self.variableName]) {
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if (error) {
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*error = MPParseError(9,
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NSLocalizedString(@"Undefined Variable.", @"Error message. This is displayed when an expression contains an undefined variable."),
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nil);
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}
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return NO;
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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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return [[MPEvaluationContext sharedContext] valueForVariable:self.variableName];
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}
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@end
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