Description:
------------
It would be very nice, if you could specify a callback for 
bbcode tags. This would be very useful for example for a forum 
etc. where you add a post-id as argument for the "quote" tag.

With a callback you could handle the argument and fetch 
further information of the quoted text, e.g.: author-name etc.


Reproduce code:
---------------
<?php

$string = <<<EOT
[quote=1234]
some-quoted-text
[/quote]

some more text
EOT;

$bbcode = array(
    ''  => array(
        'type' => BBCODE_TYPE_ROOT
    ),
    'quote' => array(
        'type'     => BBCODE_TYPE_OPTARG, 
        'open_tag' => function(arg) {
            // do some stuff here like DB lookups etc, to get additional information for specified argument
            return "<blockquote><a href="...">" . $author_name . "</a></blockquote><br />";
        },
        'close_tag' => '</blockquote>'
    )
);

$bbhandler = bbcode_create($bbcode);
bbcode_parse($bbh, $string);

?>

Expected result:
----------------
<blockquote><a href="...">author_name</a><br />
some-quoted-text
</blockquote>

some more text