[bb]中的php bbcode解析器[tag]

Question

I have simple BBCode parser:

function parse($text) {
    $text = htmlspecialchars($text);
    $text = nl2br($text);
    $text = preg_replace("#\[b\](.*?)\[/b\]#si", '<b>\\1</b>', $text);
    $text = preg_replace("#\[i\](.*?)\[/i\]#si", '<i>\\1</i>', $text);
    $text = preg_replace("#\[u\](.*?)\[/u\]#si", '<u>\\1</u>', $text);
    $text = preg_replace("#\[color=(.*?)\](.*?)\[/color\]#si", "<span style=\"color:\\1;\">\\2</span>", $text);
//and some more rules [...]
    return $text;
}

It work's good when i have simple input, but when user trying use color in color, it's not working.

For example 1:

[b]bold[color=#f00]red[/color][i]italic[/i][/b]

everything is OK, but when user try something like example 2:

[b]bold[color=#f00]red[color=#0f0]green[/color][/color][i]italic[/i][/b]

my function returns:

<b>bold<span style="color:#f00;">red[color=#0f0]green</span>[/color]<i>italic</i></b>

of course example 3 working good:

[b]bold[color=#f00]red[/color][color=#0f0]green[/color][i]italic[/i][/b]

My question is it any simple solution to build something like DOM and then parse expresion? I'd like get something like this for 2nd example:

<b>bold<span style="color:#f00;">red<span style="color:#0f0;">green</span></span><i>italic</i></b>

Answer 1

You should look into already existing solutions if you're willing to parse complex BBCode (see the post mario linked in a comment for reference).

However, if you're willing to stick with your own implementation, you can use recursive regexes, for example this way:

<?php
function bbcodeColor($input)
{
    $regex = '#\[color=(.*?)\](((?R)|.)*?)\[\/color\]#is';
    if (is_array($input)) {
        $input = '<span style="color:'.$input[1].';">'.$input[2].'</span>';
    }
    return preg_replace_callback($regex, 'bbcodeColor', $input);
}

echo bbcodeColor('[color=#f00]red[color=#0f0]green[/color][/color]');
// <span style="color:#f00;">red<span style="color:#0f0;">green</span></span>