Improved Evaluation

MathPad/MPToken.m

@@ -0,0 +1,104 @@
+//
+//  MPToken.m
+//  MathPad
+//
+//  Created by Kim Wittenburg on 19.09.14.
+//  Copyright (c) 2014 Kim Wittenburg. All rights reserved.
+//
+
+#import "MPToken.h"
+
+@implementation MPToken {
+    NSRange _range;
+    MPTokenType _tokenType;
+    NSString *_stringValue;
+}
+
+- (instancetype)initEOFTokenAtLocation:(NSUInteger)eofLocation
+{
+    self = [super init];
+    if (self) {
+        _range = NSMakeRange(eofLocation, 0);
+    }
+    return self;
+}
+
+- (instancetype)initWithRange:(NSRange)range inString:(NSString *)input
+{
+    self = [super init];
+    if (self) {
+        _range = range;
+        _stringValue = [input substringWithRange:range].copy;
+    }
+    return self;
+}
+
+- (instancetype)initWithTokenType:(MPTokenType)tokenType
+                            range:(NSRange)range
+                         inString:(NSString *)input
+{
+    self = [self initWithRange:range
+                      inString:input];
+    if (self) {
+        _tokenType = tokenType;
+    }
+    return self;
+}
+
+- (NSRange)range
+{
+    return _range;
+}
+
+- (MPTokenType)tokenType
+{
+    return _tokenType;
+}
+
+- (NSString *)stringValue
+{
+    return _stringValue;
+}
+
+- (NSString *)description
+{
+    return self.stringValue;
+}
+
+@end
+
+
+@implementation MPToken (MPTokenExtension)
+
+- (NSUInteger)numberOfOperators
+{
+    NSString *operatorString = [[self.stringValue componentsSeparatedByString:@" "] componentsJoinedByString:@""];
+    return operatorString.length;
+}
+
+- (NSDecimalNumber *)operatorValue
+{
+    NSString *operatorString = [[self.stringValue componentsSeparatedByString:@" "] componentsJoinedByString:@""];
+    NSDecimalNumber *value = [NSDecimalNumber one];
+    for (NSUInteger charIndex = 0; charIndex < operatorString.length; charIndex++) {
+        NSString *operator = [operatorString substringWithRange:NSMakeRange(charIndex, 1)];
+        if ([operator isEqualToString:@"-"]) {
+            value = [value decimalNumberByMultiplyingBy:[[NSDecimalNumber alloc] initWithInteger:-1]];
+        }
+    }
+    return value;
+}
+
+- (NSDecimalNumber *)number
+{
+    return [NSDecimalNumber decimalNumberWithString:self.stringValue
+                                             locale:[NSLocale currentLocale]];
+}
+
+- (NSString *)variable
+{
+    return self.stringValue;
+}
+
+
+@end