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Date: Wed, 14 Jan 2004 14:02:59 +0200
To: John Coggeshall <john@coggeshall.org>
Cc: PHP Internals <internals@lists.php.net>
In-Reply-To: <1074072793.19144.50.camel@coogle.localdomain>
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Subject: Re: [PHP-DEV] Weird.
From: zeev@zend.com (Zeev Suraski)
References: <1074072793.19144.50.camel@coogle.localdomain>

At 11:33 14/01/2004, John Coggeshall wrote:
>I know that this issue to some extent or another has been brought up
>before, but I just wanted to make sure that this is really how things
>are supposed to work... Apparently the statements setting B C and D
>are all equivalent.
>
>This could be absolutely bogus, but I thought maybe someone could
>explain briefly why if it is :)
>
>John
>
><?php
>         class weird {
>
>               var $myvar;
>
>               function __construct() {
>
>               $this->myvar = "A";
>               $this->$myvar = "B";
>               $this->${'myvar'} = "C";
>               $this->${'$myvar'} = "D";
>
>               echo 'this->myvar: '.$this->myvar."\n";
>               echo 'this->$myvar: '.$this->$myvar."\n";
>               echo 'this->${\'myvar\'}: '.$this->${'myvar'}."\n";
>               echo 'this->${\'$myvar\'}: '.$this->${'$myvar'}."\n";
>               echo 'this->$$$$$$$myvar: '.$this->$$$$$$$myvar."\n";
>               echo 'this->$$$$$$${\'$$$myvar\'}: ' .
>                     $this->$$$$$$${'$$$myvar'}."\n";
>
>              }
>         }
>
>?>

I don't see anything odd in here.  All of the assignments, except for the 
first one ('A'), assign to $this->"" (because $myvar, ${'myvar'} (which is 
the same as $myvar) and ${'$myvar'} (which is basically $"") are all non 
existent variables which implicitly evaluate to "".  Try to turn on E_ALL, 
it should give you some insight...

Zeev