nested quote parser example

nested_quote_parser.php

<?php
function parse_quote($matches) {
    $bbcode = '';
    preg_match_all('/(\w*?)=\'(.*?)\'/msi', $matches[1], $attr_matches);
    $attributes = array_combine($attr_matches[1], $attr_matches[2]);
    if(!empty($attributes))
    {
        $attribute_strings = array();
        foreach($attributes as $key => $value)
        {
            switch($key)
            {
                case 'id':
                    $attribute_strings[] = '<a href="http://domain.com/forums/findpost/'.$value.'">Permalink</a>';
                break;
                case 'name':
                    if(isset($quote['attributes']['user_id']))
                    {
                        $attribute_strings[] = 'By <a href="http://domain.com/user/profile/'.$attributes['user_id'].'/'.$value.'">'.$value.'</a>';
                    }
                    else
                    {
                        $attribute_strings[] = 'By '.$value;
                    }
                break;
                case 'timestamp':
                    $attribute_strings[] = 'On '.date('d F Y - H:i A', $value);
                break;
            }
        }


        {
            $citation = '<p class="citation">'.implode(' | ', $attribute_strings).'</p>'."\n";
        }
    }
    else
    {
        $citation = '';
	}

    return $citation.'<blockquote>';
}

$string = "[quote name='Rob' user_id='1' id='1' timestamp='1294120376']
[quote name='Rob' user_id='1' id='2' timestamp='1302442553']
[quote name='Rob' user_id='1' id='3' timestamp='1302442553']
Test at a comment of a third depth
[/quote]
Lorem ipsum dolor sit amet
[/quote]
This is my comment
[/quote]

[b]Test Comment[/b]";

$new_string = str_replace('[/quote]', '</blockquote>', $string);
echo preg_replace_callback('/\[quote(.*?)\]/msi','parse_quote', $new_string);