dynamic_function.php

<?php

class Foo {
  function __construct($method) {
    $this->$method = create_function('', 'print "foobar";');
  }
  
  public function __call($name, $arguments) {
    call_user_func($this->$name, $arguments);
  }
  

}

$f = new Foo('my_method');
$f->my_method();