Edit report at http://bugs.php.net/bug.php?id=53138&edit=1
ID: 53138
Comment by: tom at r dot je
Reported by: tom at r dot je
Summary: __instanceof magic method
Status: Bogus
Type: Feature/Change Request
Package: *General Issues
Operating System: N/A
PHP Version: 5.3.3
Block user comment: N
New Comment:
Why is that?
While that solution works, it's clunky.
For example for debugging/logging I may want to do something prior to
each
method call:
class Wrapper {
protected $object;
private function log($details) {
}
public function __construct($object) {
$this->object = $object;
}
public function __set($name, $value) {
$this->object->$name = $value;
}
public function __get($name) {
return $this->object->$name;
}
public function __call($func, $args) {
$this->log('Called ' . $func);
return call_user_func_array(array($this->object, $func), $args);
}
}
?>
Essentially the adapter pattern for any object. This works until you
pass it
around.
Extending the A wont work because:
__call will never get called because the methods exist
Also, this wrapper class could wrap *any* class in the system. Extending
every
class isn't viable.
Previous Comments:
------------------------------------------------------------------------
[2010-10-22 15:17:15] cataphr...@php.net
Make A an interface and have AWrapper implement or extend A.
Overloading the instanceof operator is not an acceptable solution.
------------------------------------------------------------------------
[2010-10-22 13:00:23] tom at r dot je
Description:
------------
as it stands, it's possible to create a wrapper e.g.
<?php
class A {
}
class AWrapper {
protected $a;
public function __construct(A $a) {
$this->a = $a;
}
public function __set($name, $value) {
$this->a->$name = $value;
}
public function __get($name) {
return $this->a->$name;
}
public function __call($func, $args) {
return call_user_func_array(array($this->a, $func), $args);
}
}
?>
AWrapper, now mimics the interface of A. It will work as a substitute
for A, anywhere A is required.
The problem is, type checking. Anywhere class "A" is used, it may be
type hinted or checked using instanceof
e.g.
function setA(A $a) {
}
or $foo isntanceof 'A';
If an __instanceof magic method existed, it would be possible to get
around this and have true wrapper classes.
For example:
public function __instanceof() {
return 'A';
}
Or perhaps it should return an array to allow it to wrap multiple
classes.
------------------------------------------------------------------------
--
Edit this bug report at http://bugs.php.net/bug.php?id=53138&edit=1
