Use this to dynamically register
prefilters
to run templates through before they are compiled. See template prefilters for
more information on how to setup a prefiltering function.
The php-function callback function can be either:
A string containing the function name
An array of the form array(&$object, $method) with
&$object being a reference to an
object and $method being a string
containing the method-name
An array of the form
array($class, $method) with
$class being the class name and
$method being a method of the class.