Plug in
 

Before it is mentioned - I realise how seriously unsecure this is but I will take the necessary precautions.

I was hoping to create a plug in using the bbcode_fetch_tags which parses PHP script in the bbcode tags. I wanted to use this for such pranks like
[phpparsecode]echo "$_SERVER['REMOTE_ADDR']"[/phpparsecode]
I realise a lot of you probably feel like this is pointless or whatever but i'd like to create this.

How would I go about creating the bbcode tags and hooking it to the plug in?

The example will not work with the standard BB code system, as posts are fully parsed, then cached for X amount of time. You are better off doing an eval() at a plugin at postbit_display_complete.

I can't stress enough how dangerous this is!

Does the eval() function parse the PHP as it is displayed? Thus displaying all PHP codes as it is parsed?

Also, how would I call the input using eval(), I am not familiar with vBulletin's global variables.

<a href="http://www.php.net/manual/en/function.eval.php" target="_blank">http://www.php.net/manual/en/function.eval.php</a>

I have tried reading and understanding the use of eval(), with no success.
Could anyone help me implement this into my vBulletin?

Honestly, if you don't understand how PHP (or specifically eval()) does work you should not code such an Add-on (in fact nobody should anyway).