Egg, why don't you start by trying out some programming.
public function isViewable($isLoggedIn)
{
if ($this->idparent === IDPARENT_HEADER) return true;
elseif ($this->parent === null && !$isLoggedIn) return false;
else {return $this->parent->isViewable($isLoggedIn);}
}
The function belongs to my Article class, objects of which are linked in a hierarchy using the idparent member. Obviously the function works recursively up the hierarchy by calling itself.
Tell me why this keeps throwing an error. Any ideas?