Your function can be treated as a callback function so call_user_func()
will work to invoke the returned function. You can call the function like so...
http://be2.php.net/function.call-user-func
class AClass {
public function getFnc() {
$f = function() {
echo "hello from a function";
};
return $f;
}
}
$c = new AClass();
call_user_func($c->getFnc());