note 56451 modified in function.runkit-class-adopt by danbrown
| From: | danbrown@php.net | Date: | Sun, 20 Jul 2008 01:24:20 +0000 |
| Subject: | note 56451 modified in function.runkit-class-adopt by danbrown | ||
| References: | 1 | Groups: | php.notes |
| Request: | Send a blank email to php-notes+get-141908@lists.php.net to get a copy of this message | ||
Function visibility (in PHP5) has some quirks as compared to the normal behavior with
"extends". Consider the following:
<?php
class base {
public function a() { $this->b(); }
private function b() { echo "This is b()"; }
}
?>
This will work fine:
<?php
class inherit extends base {
public function c() { $this->a(); }
}
$x = new inherit;
$x->c();
?>
while this:
<?php
class adopt {
public function c() { $this->a(); }
}
runkit_class_adopt('adopt','base');
$x = new adopt;
$x->c();
?>
will generate a fatal "Call to private method base::b() from context 'adopt'"
error. Protected members can be called from the inherited methods, but still cannot be called from
the original class (i.e. if b() were declared protected, the example would work as written, but
adopt::c() still could not call base::b() directly.
Functions such as is_subclass_of(), is_a(), and the instanceof operator also do not detect the new
lineage of the object; if you are using this function to simulate multiple or dynamic inheritance,
you may need to implement your own method of determining class lineage.
[EDIT by danbrown AT php DOT net: Merged addendum to post by original author.]
--was--
Function visibility (in PHP5) has some quirks as compared to the normal behavior with
"extends". Consider the following:
class base {
public function a() { $this->b(); }
private function b() { echo "This is b()"; }
}
This will work fine:
class inherit extends base {
public function c() { $this->a(); }
}
$x = new inherit;
$x->c();
while this:
class adopt {
public function c() { $this->a(); }
}
runkit_class_adopt('adopt','base');
$x = new adopt;
$x->c();
will generate a fatal "Call to private method base::b() from context 'adopt'"
error. Protected members can be called from the inherited methods, but still cannot be called from
the original class (i.e. if b() were declared protected, the example would work as written, but
adopt::c() still could not call base::b() directly.
http://php.net/manual/en/function.runkit-class-adopt.php