[Xenon]

ok, well here it is, as i said, it's not a released hack, no support is given

open admin functions.php
in function gettemplate find this:

PHP Code:

  if ($escape==1) {
    $template=addslashes($template);
    $template=str_replace("\\'","'",$template);
  } 


below just add:

PHP Code:

  // conditionals
  $template=str_replace("<if>","\".iif(",$template);
  $template=str_replace("<then>",",\"",$template);
  $template=str_replace("<else>","\",\"",$template);
  $template=str_replace("</if>","\").\"",$template); 


then in templates you have to use <if><then><else></if> constructions:

Example:

Hello <if>$bbuserinfo[userid]>0<then>$bbuserinfo[username]<else>Guest, please register</if>

as said, be carefule, it can easily produce parseerrors if you use wrong conditions
It just fits my needs, not any checks