note 109639 modified in language.oop5.late-static-bindings by danbrown

From:	danbrown@php.net	Date:	Fri, 10 Aug 2012 16:16:14 +0000
Subject:	note 109639 modified in language.oop5.late-static-bindings by danbrown
References:	1	Groups:	php.notes
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For static properties declared in parent class and not redeclared in sub-classes, static:: in parent class would hit parent's properies. (class a and b below)
If those were declared in sub-classes, static:: in parent class will hit sub-classes's own. (class c and d below).

e.g.

<?php

$_CONFIG['a'] = '1';
$_CONFIG['b'] = '2';
$_CONFIG['c'] = '3';
$_CONFIG['d'] = '4';

class static_base
{
 static protected $config;
 static protected $module_name = '';
 static public function load()
 {
 global $_CONFIG;
 static::$config = $_CONFIG[static::$module_name];
 }
 static public function dump()
 {
 var_dump(static::$config);
 }
}

class a extends static_base
{
 static protected $module_name = 'a';
}

class b extends static_base
{
 static protected $module_name = 'b';
}

class c extends static_base
{
 static protected $module_name = 'c';
 static protected $config;
}
class d extends static_base
{
 static protected $module_name = 'd';
 static protected $config;
}

a::load();
b::load();
a::dump(); // 2
b::dump(); // 2

c::load();
d::load();
c::dump(); // 3
d::dump(); // 4
?> --was-- For static properties declared in parent class and not redeclared in sub-classes, static:: in parent class would hit parent's properies. (class a and b below) If those were declared in sub-classes, static:: in parent class will hit sub-classes's own. (class c and d below). e.g. <?php $_CONFIG['a'] = '1'; $_CONFIG['b'] = '2'; $_CONFIG['c'] = '3'; $_CONFIG['d'] = '4'; class static_base { static protected $config; static protected $module_name = ''; static public function load() { global $_CONFIG; static::$config = $_CONFIG[static::$module_name]; } static public function dump() { var_dump(static::$config); } } class a extends static_base { static protected $module_name = 'a'; } class b extends static_base { static protected $module_name = 'b'; } class c extends static_base { static protected $module_name = 'c'; static protected $config; } class d extends static_base { static protected $module_name = 'd'; static protected $config; } a::load(); b::load(); a::dump(); // 2 b::dump(); // 2 c::load(); d::load(); c::dump(); // 3 d::dump(); // 4 http://php.net/manual/en/language.oop5.late-static-bindings.php