Question

Switching the code of the debate forum on my website, I am going to change the way quotes are stored in the database. Now I need to come up with a regex to rearrange already submitted posts in my database.

Following is an example of how my current debate post are stored in the database (with quotes in quotes).. Note: I have indented it for the sake of illustration:

Just citing a post
[quote]Text of quote #3
       [quote]Text of quote #2
              [quote]Text of quote #1
                     [name]User 1[/name]
              [/quote]
              [name]User 2[/name]
       [/quote]
       [name]User 3[/name]
[/quote]

What I would like now, is that the former will be rearranged to look like this:

Just citing a post
[quote:User 3]
      Text of quote #3
      [quote:User 2]
           Text of quote #2
           [quote:User 1]
                 Text of quote #1
           [/quote]  
      [/quote]   
[/quote]

Can any of you point me in the direction of how this can be done with regex? I am using PHP.

Thanks in advance, I appreciate all your help 🙂

Fischer

Answer 1

This will do it:

$input = "Just citing a post
[quote]Text of quote #3
       [quote]Text of quote #2
              [quote]Text of quote #1
                     [name]User 1[/name]
              [/quote]
              [name]User 2[/name]
       [/quote]
       [name]User 3[/name]
[/quote]";

function fix_quotes($string) {
    $regexp = '`(\s*)\[quote\]((?:[^\[]|\[(?!quote\]))*?)\[name\](.*?)\[\/name\]\s*\[\/quote\]`';
    while (preg_match($regexp, $string)) {
        $string = preg_replace_callback($regexp, function($match) {
            return $match[1] . '[quote:' . $match[3] . ']' . trim(fix_quotes($match[2])) . $match[1] . '[/quote]';
        }, $string);
    }
    return $string;
}

echo fix_quotes($input);

Results in:

Just citing a post
[quote:User 3]Text of quote #3
       [quote:User 2]Text of quote #2
              [quote:User 1]Text of quote #1
              [/quote]
       [/quote]
[/quote]

Edit: haven’t seen that joelhardi already posted similar solution, and his looks a bit cleaner so I’d stick with his solution 🙂