Question: I am trying to hack an ACL into a Template without making the Template aware of the ACL object in the class definition. The following code generates an undefined method Template::isAllowed 

Why is this? TIA!

```

        class ACL {
                protected $allowed = array('anything');

                public function isAllowed($what){
                        if(in_array($what, $this->allowed))
                                return true;
                        return false;
                }
        }

        class Template extends stdClass { }

        $Template = new Template;
        $ACL = new ACL;
        $Template->isAllowed = function($what) use($ACL) { return $ACL->isAllowed($what); };

        if($Template->isAllowed('anything'))
                echo 1;
        else
                echo 2;
```

Answer: 
This:

```
$Template->isAllowed('anything')

```

actually tells PHP to call a method `Template::isAllowed()`, which obviously doesn't exist as given by your fatal error.

You cannot treat `Template::isAllowed()` as if it were a real method by assigning a closure to a property. However you can still call the closure that is assigned to the `$Template->isAllowed` property (which is an instance of [`Closure`](http://www.php.net/manual/en/reserved.classes.php#reserved.classes.closure)). To do that, you need to either assign the property to a variable then call that:

```
$isAllowed = $Template->isAllowed;

if ($isAllowed('anything'))
    echo 1;
else
    echo 2;

```

Or use `call_user_func()`:

```
if (call_user_func($Template->isAllowed, 'anything'))
    echo 1;
else
    echo 2;

```
Simply this does not work -- you can not add class methods dynamically in PHP, period. This was discussed at places like [define a closure as method from class](https://stackoverflow.com/questions/2881311/define-a-closure-as-method-from-class).