String capitalization for NSString while keeping roman numerals all capitalized.

NSString+Punctuation.h

//
// NSString+Punctuation.h
// by Ali Servet Donmez <asd NOSPAM pittle.org>, 2010
// http://www.pittle.org/
//

/*
 * Requirements
 * ------------
 *   - "RegexKitLite" (http://regexkit.sourceforge.net/#RegexKitLite)
 *
 * Shameless documentation
 * -----------------------
 *   This will add string capitalization for NSString while keeping roman numerals all capitalized.
 *   For instance:
 *     [@"WORLD WAR III" capitalizedString];                  // "World War Iii" (ugly...)
 *     [@"WORLD WAR III" capitalizedStringWithRomanNumerals]; // "World War III" (sweet!)
 *
 */

#import <Foundation/Foundation.h>

@interface NSString (Punctuation)

- (id)capitalizedStringWithRomanNumerals;

@end

NSString+Punctuation.m

//
// NSString+Punctuation.m
// by Ali Servet Donmez <asd NOSPAM pittle.org>, 2010
// http://www.pittle.org/
//

#import "NSString+Punctuation.h"
#import "RegexKitLite.h"

@implementation NSString (Punctuation)

- (id)capitalizedStringWithRomanNumerals
{
    self = [self capitalizedString];
    
    NSString *regEx = @"(?<=(?:^|\\s{1,2}|[(\\[]))(X{0,3}(?:IX|IV|V?I{0,3}))(?=(?:[)\\]]|\\s{1,2}|$))";

    NSError *regexValidError = NULL;
    if([regEx isRegexValidWithOptions:RKLNoOptions error:&regexValidError] == NO) {
        DebugLog(@"The regular expression is invalid. Error: %@", regexValidError);
    }

    NSError *replaceError = NULL;
    
    self = [self stringByReplacingOccurrencesOfRegex:regEx
                                             options:RKLCaseless
                                             inRange:NSMakeRange(0UL, [self length])
                                               error:&replaceError
                                  enumerationOptions:RKLRegexEnumerationNoOptions
                                          usingBlock:
            ^(NSInteger captureCount,
              NSString * const capturedStrings[captureCount],
              const NSRange capturedRanges[captureCount],
              volatile BOOL * const stop) {
                return (NSString *)([NSString stringWithFormat:@"%@",
                                     [capturedStrings[1] uppercaseString]]);
            }];
    
    if (replaceError != NULL) {
        DebugLog(@"Error in replace: %@", replaceError);
    }

    return self;
}

@end