Implemented Expression Evaluation/Parsing with Proper Error Handling

MathPad/NSRegularExpression+MPParsingAdditions.m

@@ -0,0 +1,33 @@
+//
+//  NSRegularExpression+MPParsingAdditions.m
+//  MathPad
+//
+//  Created by Kim Wittenburg on 09.09.14.
+//  Copyright (c) 2014 Kim Wittenburg. All rights reserved.
+//
+
+#import "NSRegularExpression+MPParsingAdditions.h"
+
+@implementation NSRegularExpression (MPParsingAdditions)
+
+- (NSTextCheckingResult *)firstMatchInString:(NSString *)string
+{
+    return [self firstMatchInString:string options:0 range:MPStringRange(string)];
+}
+
+- (NSTextCheckingResult *)firstMatchInString:(NSString *)string fromIndex:(NSUInteger)start
+{
+    return [self firstMatchInString:string options:0 range:NSMakeRange(start, [string length]-start)];
+}
+
+- (NSTextCheckingResult *)firstMatchInString:(NSString *)string options:(NSMatchingOptions)options
+{
+    return [self firstMatchInString:string options:options range:MPStringRange(string)];
+}
+
+- (NSTextCheckingResult *)firstMatchInString:(NSString *)string options:(NSMatchingOptions)options fromIndex:(NSUInteger)start
+{
+    return [self firstMatchInString:string options:options range:NSMakeRange(start, [string length]-start)];
+}
+
+@end