Solution for http://pastebin.com/ANhr7BMr

Snippet.mm

- (void)modifySelectedString: (NSDictionary *)theAttribute {
    NSString *mainString = [self.mainStringLabel.attributedText string];
    NSString *queryString = [self selectStringFromMainStringLabelViaStepper];
    
    NSRange selectedStringRange = NSMakeRange(0, mainString.length);
    while (selectedStringRange.location != NSNotFound) {
        NSRange selectedStringRange = [mainString rangeOfString:queryString options:0 range:selectedStringRange];
        
        if (selectedStringRange.location != NSNotFound) {
            [self addAttributeWithRangeToSelectedString:theAttribute range:selectedStringRange];
            
            NSInteger nextIndex = selectedStringRange.location + selectedStringRange.length + 1;
            selectedStringRange = NSMakeRange(nextIndex, mainString.length - nextIndex);
        }
    }
}