Deactivate a function on a case by case basis

[Marcus]

I want to deactivate a function on a case by case basis. If a parameter comes up, the function should be disabled. Currently I can only disable the function by deactivating it completely:

  public function canonicalizeRequestUrl($linkUrl)
   {    
   }

The idea is here, that my virtual forums are accessed by &virtual_node_id (forums/5/&virtual_node_id=10 and ControllerPublic_Forum::actionForum will redirect with the above function whenever I manipulate node_id:

    $this->canonicalizeRequestUrl(
       XenForo_Link::buildPublicLink('forums', $forum, array('page' => $page))
     );

Is there a way in php to deactivate a function on a case by case basis?

 

[EasyTarget]

If (x == true)
{
Do stuff
}
Else
{
// do nothing
}

 

[tyteen4a03]

If (x == true)
{
Do stuff
}
Else
{
// do nothing
}

Or

if (things) {
do(stuff);
}

No else clause necessary.