note 79743 deleted from language.oop5.abstract by felipe
| From: | felipe@php.net | Date: | Sat, 15 Dec 2007 15:35:31 +0000 |
| Subject: | note 79743 deleted from language.oop5.abstract by felipe | ||
| References: | 1 | Groups: | php.notes |
| Request: | Send a blank email to php-notes+get-133577@lists.php.net to get a copy of this message | ||
Note Submitter: michikono at gmail dot com
----
When trying to enforce arguments on constructors, PHP behaves unexpectedly.
First, look at this example where a constructor argument count and type are specified in an
interface:
<?php
class ExampleClass {}
interface TestInterface {
public function __construct(ExampleClass $var);
public function output(ExampleClass $var);
}
class Test implements TestInterface {
// error, no constructor method
public function output($var) {} // error, wrong argument type
}
?>
However, if you define the constructor, the __construct method argument datatype/count checks go out
the window:
<?php
class Test implements TestInterface {
public function __construct() {} // NO ERROR (unexpected)
public function output(ExampleClass $var) {} // No error (expected)
?>
Despite the data types and argument count being off, PHP doesn't care. Even if I define an
argument in the constructor, the datatype check is ignored. So the best you can do is force a
__construct() definition to be required, but you can't dictate its arguments (i.e., interfaces
for constructor methods are useless).
This problem produces the SAME results if instead of an interface, abstract methods in an abstract
parent class are used.