Improved Evaluation

2014-09-28 23:50:18 +02:00
parent 43b6f78afb
commit d67a1949e9
19 changed files with 841 additions and 89 deletions
--- a/MathPad/MPExpressionTokenizer.m
+++ b/MathPad/MPExpressionTokenizer.m
@@ -0,0 +1,115 @@
+//
+//  MPExpressionLexer.m
+//  MathPad
+//
+//  Created by Kim Wittenburg on 19.09.14.
+//  Copyright (c) 2014 Kim Wittenburg. All rights reserved.
+//
+
+#import "MPExpressionTokenizer.h"
+#import "MPToken.h"
+#import "MPFunction+MPToken.h"
+
+#import "NSRegularExpression+MPParsingAdditions.h"
+
+
+#define MPRangeExists(range) (range.location != NSNotFound)
+
+
+@implementation MPExpressionTokenizer
+
+- (NSArray *)tokenizeExpression:(MPExpression *)expression
+{
+    NSMutableArray *tokens = [[NSMutableArray alloc] init];
+    for (NSUInteger index = 0; index < expression.numberOfElements; index++) {
+        id <MPExpressionElement> element = [expression elementAtIndex:index];
+        if ([element isFunction]) {
+            [tokens addObject:element];
+        } else {
+            [tokens addObjectsFromArray:[self tokenizeElement:(NSString *)element]];
+        }
+    }
+    return tokens;
+}
+
+- (NSArray *)tokenizeElement:(NSString *)element
+{
+    NSUInteger lexLocation = 0;
+    
+    NSString *decimalSeparator = [NSRegularExpression escapedPatternForString:[[NSLocale currentLocale] objectForKey:NSLocaleDecimalSeparator]];
+    NSString *regexStringFormat = @"\\A(?:"
+                            @"(\\*)|"
+                            @"([+-](?:\\s*[+-])*)|"
+                            @"((?:\\d+(?:%@\\d+)?)|(?:\\s%@\\d+))|"
+                            @"(sin)|"
+                            @"(cos)|"
+                            @"(tan)|"
+                            @"([A-Za-z])|"
+                            @"(=)|"
+                            @"(\\s)"
+                            @")";
+    NSString *regexString = [NSString stringWithFormat:regexStringFormat, decimalSeparator, decimalSeparator];
+    NSRegularExpression *regex = [NSRegularExpression regularExpressionWithPattern:regexString
+                                                                           options:0
+                                                                             error:NULL];
+    NSMutableArray *tokens = [[NSMutableArray alloc] init];
+    while (lexLocation < element.length) {
+        NSTextCheckingResult *match = [regex firstMatchInString:element fromIndex:lexLocation];
+        
+        NSRange range = NSMakeRange(lexLocation, 1);
+        MPTokenType tokenType = MPUnidentifiedToken;
+        if (match) {
+            NSRange multiplicationSymbolRange = [match rangeAtIndex:1];
+            NSRange operatorRange = [match rangeAtIndex:2];
+            NSRange numberRange = [match rangeAtIndex:3];
+            NSRange sinRange = [match rangeAtIndex:4];
+            NSRange cosRange = [match rangeAtIndex:5];
+            NSRange tanRange = [match rangeAtIndex:6];
+            NSRange variableRange = [match rangeAtIndex:7];
+            NSRange equalsRange = [match rangeAtIndex:8];
+            NSRange whitespaceRange = [match rangeAtIndex:9];
+        
+            if (MPRangeExists(multiplicationSymbolRange)) {
+                range = multiplicationSymbolRange;
+                tokenType = MPMultiplicationSymbolToken;
+            } else if (MPRangeExists(operatorRange)) {
+                range = operatorRange;
+                tokenType = MPOperatorListToken;
+            } else if (MPRangeExists(numberRange)) {
+                range = numberRange;
+                tokenType = MPNumberToken;
+            } else if (MPRangeExists(sinRange)) {
+                range = sinRange;
+                tokenType = MPSinToken;
+            } else if (MPRangeExists(cosRange)) {
+                range = cosRange;
+                tokenType = MPCosToken;
+            } else if (MPRangeExists(tanRange)) {
+                range = tanRange;
+                tokenType = MPTanToken;
+            } else if (MPRangeExists(variableRange)) {
+                range = variableRange;
+                tokenType = MPVariableToken;
+            } else if (MPRangeExists(equalsRange)) {
+                range = equalsRange;
+                tokenType = MPEqualsToken;
+            } else if (MPRangeExists(whitespaceRange)) {
+                range = whitespaceRange;
+                tokenType = MPWhitespaceToken;
+            } else {
+                // Should not get here
+                range = NSMakeRange(lexLocation, 1);
+                tokenType = MPUnidentifiedToken;
+            }
+        }
+        
+        lexLocation = NSMaxRange(range);
+        [tokens addObject:[[MPToken alloc] initWithTokenType:tokenType
+                                                       range:range
+                                                    inString:element]];
+    }
+    
+    return tokens;
+}
+
+@end