after

    NSMutableArray *banBookey = [NSMutableArray array];
    
    [string enumerateSubstringsInRange:NSMakeRange(0, string.length) options:NSStringEnumerationByLines usingBlock:^(NSString *substring, NSRange substringRange, NSRange enclosingRange, BOOL *stop) {
        for (id key in patternsByLine) {
            NSRegularExpression *regex = [NSRegularExpression regularExpressionWithPattern:patternsByLine[key] options:NSRegularExpressionCaseInsensitive error:&error];
            
            [regex enumerateMatchesInString:substring options:0 range:NSMakeRange(0, substring.length) usingBlock:^(NSTextCheckingResult *match, NSMatchingFlags flags, BOOL *stop) {
                unsigned long startBan = substringRange.location + match.range.location;
                unsigned long endBan = startBan + match.range.length;
                BOOL paint = YES;
                
                for (unsigned long i = startBan; i < endBan; i++) {
                    NSNumber *num = [NSNumber numberWithUnsignedLong:i];
                    if ([banBookey containsObject:num]) {
                        paint = NO;
                    } else {
                        [banBookey addObject:num];
                    }
                }
                
                if (paint) {
                    [attrString addAttributes:attributes[key] range:substringRange];
                    
                    NSRange colorRange = match.range;
                    colorRange.location = colorRange.location + substringRange.location;
                    [attrString addAttributes:attributes[SHTagAttributes] range:colorRange];
                }
            }];
        }
    }];
    
    for (id key in patterns) {
        NSRegularExpression *regex = [NSRegularExpression regularExpressionWithPattern:patterns[key] options:NSRegularExpressionCaseInsensitive error:&error];
        
        [regex enumerateMatchesInString:string options:0 range:NSMakeRange(0, string.length) usingBlock:^(NSTextCheckingResult *match, NSMatchingFlags flags, BOOL *stop) {
            unsigned long startBan = match.range.location;
            unsigned long endBan = startBan + match.range.length;
            BOOL paint = YES;
            
            for (unsigned long i = startBan; i < endBan; i++) {
                NSNumber *num = [NSNumber numberWithUnsignedLong:i];
                if ([banBookey containsObject:num]) {
                    paint = NO;
                } else {
                    [banBookey addObject:num];
                }
            }
            
            if (paint) {
                [attrString addAttributes:attributes[key] range:match.range];
                [attrString addAttributes:attributes[SHTagAttributes] range:[match rangeAtIndex:1]];
                [attrString addAttributes:attributes[SHTagAttributes] range:[match rangeAtIndex:3]];
            }
        }];
    }

before

//     match headings and lists
    
    NSRegularExpression *heading1Regex = [NSRegularExpression regularExpressionWithPattern:@"(\\A|\\n)\\s?#" options:NSRegularExpressionCaseInsensitive error:&error];
    
    NSRegularExpression *heading2Regex = [NSRegularExpression regularExpressionWithPattern:@"(\\A|\\n)\\s?##" options:NSRegularExpressionCaseInsensitive error:&error];
    
    NSRegularExpression *heading3Regex = [NSRegularExpression regularExpressionWithPattern:@"(\\A|\\n)\\s?###" options:NSRegularExpressionCaseInsensitive error:&error];
    
    NSRegularExpression *listRegex = [NSRegularExpression regularExpressionWithPattern:@"(\\A|\\n)\\s?[*-]\\s?" options:NSRegularExpressionCaseInsensitive error:&error];
    
    [string enumerateSubstringsInRange:NSMakeRange(0, string.length) options:NSStringEnumerationByLines usingBlock:^(NSString *substring, NSRange substringRange, NSRange enclosingRange, BOOL *stop) {
        
        // lists
        
        [listRegex enumerateMatchesInString:substring options:0 range:NSMakeRange(0, substring.length) usingBlock:^(NSTextCheckingResult *match, NSMatchingFlags flags, BOOL *stop) {
            [attrString addAttributes:attributes[SHListParagraphAttributes] range:substringRange];
            
            NSRange colorRange = match.range;
            colorRange.location = colorRange.location + substringRange.location;
            [attrString addAttributes:attributes[SHTagAttributes] range:colorRange];
        }];
        
        // heading 1
        
        [heading1Regex enumerateMatchesInString:substring options:0 range:NSMakeRange(0, substring.length) usingBlock:^(NSTextCheckingResult *match, NSMatchingFlags flags, BOOL *stop) {
            [attrString addAttributes:attributes[SHHeading1Attributes] range:substringRange];
            
            NSRange colorStartRange = NSMakeRange(substringRange.location, 1);
            [attrString addAttributes:attributes[SHTagAttributes] range:colorStartRange];
        }];
        
        // heading 2
        
        [heading2Regex enumerateMatchesInString:substring options:0 range:NSMakeRange(0, substring.length) usingBlock:^(NSTextCheckingResult *match, NSMatchingFlags flags, BOOL *stop) {
            [attrString addAttributes:attributes[SHHeading2Attributes] range:substringRange];
            
            NSRange colorStartRange = NSMakeRange(substringRange.location, 2);
            [attrString addAttributes:attributes[SHTagAttributes] range:colorStartRange];
        }];
        
        // heading 3
        
        [heading3Regex enumerateMatchesInString:substring options:0 range:NSMakeRange(0, substring.length) usingBlock:^(NSTextCheckingResult *match, NSMatchingFlags flags, BOOL *stop) {
            [attrString addAttributes:attributes[SHHeading3Attributes] range:substringRange];
            
            NSRange colorStartRange = NSMakeRange(substringRange.location, 3);
            [attrString addAttributes:attributes[SHTagAttributes] range:colorStartRange];
        }];
    }];
    
    // highlight urls

    NSDataDetector *detector = [NSDataDetector dataDetectorWithTypes:NSTextCheckingTypeLink error:&error];
    [detector enumerateMatchesInString:string
                               options:kNilOptions
                                 range:NSMakeRange(0, string.length)
                            usingBlock:
     ^(NSTextCheckingResult *result, NSMatchingFlags flags, BOOL *stop) {
         [attrString addAttributes:attributes[SHURLAttributes] range:result.range];
     }];
    
    // italic
    
    NSRegularExpression *italicRegex = [NSRegularExpression regularExpressionWithPattern:@"(\\*|\\_)(.+?)(\\*|\\_)" options:NSRegularExpressionCaseInsensitive error:&error];
    
    [italicRegex enumerateMatchesInString:string options:0 range:NSMakeRange(0, string.length) usingBlock:^(NSTextCheckingResult *match, NSMatchingFlags flags, BOOL *stop) {
        [attrString addAttributes:attributes[SHItalicAttributes] range:match.range];
        
        NSRange colorStartRange = NSMakeRange(match.range.location, 1);
        NSRange colorEndRange = NSMakeRange(match.range.location + match.range.length - 1, 1);
        [attrString addAttributes:attributes[SHTagAttributes] range:colorStartRange];
        [attrString addAttributes:attributes[SHTagAttributes] range:colorEndRange];
    }];
    
    // bold
    
    NSRegularExpression *boldRegex = [NSRegularExpression regularExpressionWithPattern:@"(\\*\\*|\\_\\_)(.+?)(\\*\\*|\\_\\_)" options:NSRegularExpressionCaseInsensitive error:&error];
    
    [boldRegex enumerateMatchesInString:string options:0 range:NSMakeRange(0, string.length) usingBlock:^(NSTextCheckingResult *match, NSMatchingFlags flags, BOOL *stop) {
        [attrString addAttributes:attributes[SHBoldAttributes] range:match.range];
        
        NSRange colorStartRange = NSMakeRange(match.range.location, 2);
        NSRange colorEndRange = NSMakeRange(match.range.location + match.range.length - 2, 2);
        [attrString addAttributes:attributes[SHTagAttributes] range:colorStartRange];
        [attrString addAttributes:attributes[SHTagAttributes] range:colorEndRange];
    }];

setup

    NSDictionary *attributes = [TextStyle getAttributes];
    NSMutableAttributedString *attrString = [[NSMutableAttributedString alloc] initWithString:string];
    [attrString addAttributes:attributes[SHDefaultAttributes] range:NSMakeRange(0, attrString.length)];
    __block NSError *error = nil;
    
    NSMutableDictionary *patternsByLine = [@{} mutableCopy];
    patternsByLine[SHHeading1Attributes] = @"(\\A|\\n)\\s?#[^\\#]";
    patternsByLine[SHHeading2Attributes] = @"(\\A|\\n)\\s?##[^\\#]";
    patternsByLine[SHHeading3Attributes] = @"(\\A|\\n)\\s?###[^\\#]";
    patternsByLine[SHListParagraphAttributes] = @"(\\A|\\n)\\s?[*-]\\s";
    
    NSMutableDictionary *patterns = [@{} mutableCopy];
    patterns[SHItalicAttributes] = @"(\\*|\\_)(.+?)(\\*|\\_)";
    patterns[SHBoldAttributes] = @"(\\*\\*|\\_\\_)(.+?)(\\*\\*|\\_\\_)";