Everything

php

Weird.

php.internals

John Coggeshall

22 years ago

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";

}
}

?>

--
-=~=--=~=--=~=--=~=--=~=--=~=--=~=--=~=--=~=--=~=--=~=--=~=-
John Coggeshall                   http://www.coggeshall.org/
The PHP Developer's Handbook    http://www.php-handbook.com/
-=~=--=~=--=~=--=~=--=~=--=~=--=~=--=~=--=~=--=~=--=~=--=~=-

messju mohr

22 years ago

On Wed, Jan 14, 2004 at 04:33:13AM -0500, 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 :)

"B" and "C" are equivalent but "D" is somethig else.

"B" and "C" set the property named by the value of $myvar.
in "D" the variable-name is '$myvar' (not 'myvar').

if you set

$myvar = "foo";
${'$myvar'} = "bar";

then "B" and "C" will set $this->foo, but "D" will set $this->bar.

it's not that bogus.

greetings
messju

Zeev Suraski

22 years ago

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

John Coggeshall

22 years ago

> 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...

Ah, that makes it very obvious! I thought I had E_ALL enabled ;)

John

--
-=~=--=~=--=~=--=~=--=~=--=~=--=~=--=~=--=~=--=~=--=~=--=~=-
John Coggeshall                   http://www.coggeshall.org/
The PHP Developer's Handbook    http://www.php-handbook.com/
-=~=--=~=--=~=--=~=--=~=--=~=--=~=--=~=--=~=--=~=--=~=--=~=-