Use this code snippet to test your regular expression syntax.

regex-tester.m

//
//  regex-tester.m
//  Alexis Digital
//
//  Created by Jeff Kereakoglow on 1/23/15.
//
//  Use this code snippet to test your regular expression syntax.
//

#import <Foundation/Foundation.h>

int main(int argc, const char *argv[]) {
  @autoreleasepool {
    NSString *regex;
    NSString *text;
    NSPredicate *predicate;
    BOOL isValid = NO;

    // Get the command-line arguments
    if([NSProcessInfo processInfo].arguments.count >= 3) {
      regex = [NSProcessInfo processInfo].arguments[1];
      text  = [NSProcessInfo processInfo].arguments[2];

      predicate = [NSPredicate predicateWithFormat:@"SELF MATCHES %@", regex];

      isValid = [predicate evaluateWithObject:[text stringByTrimmingCharactersInSet:[NSCharacterSet whitespaceCharacterSet]]];

      NSLog(@"\n\n Regex:  %@\n Text:   %@\n Result: %@\n\n", regex, text, ((isValid) ? @"Valid" : @"Invalid"));
    }

    else {
      NSLog(@"\n\n Not enough arguments");
    }
  }

  return 0;
}

Description

I have a hard time writing regular expressions that are compatible with Cocoa. I wrote this small program to quickly test to see if my syntax is correct.

Compilation

Compile with this command

clang -fobjc-arc regex-tester.m -o regex-tester

And execute with this command

$ .\regex-tester ^(your|regex)$ The text you want to match against

To see this result

$ ./regex-tester ^\\d$ 0
2015-01-23 15:38:08.567 regex[11219:219404] 

 Regex:  ^\d$
 Text:   0
 Result: Valid