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Date: Thu, 3 Feb 2005 16:31:25 -0800
Lines: 42
Subject: Re: referencing Superglobals with variable variables inside functions
From: pollita@php.net ("Sara Golemon")

> ok, i see. But why does it work with variables that are set as global, 
> e.g. the $HTTP_*_VARS:
>
> <?php
> function test() {
>     global $HTTP_GET_VARS;
>     $a = 'HTTP_GET_VARS';
>     var_dump($$a);
> }
> test();
> ?>
>
global $foo;
is the equivalent of:
$foo = &$GLOBALS['foo'];

So when you access $$a, you're getting 'HTTP_GET_VARS' from the LOCAL symbol 
table (where it exists as a reference of the global symtable version).

> this works inside a function. is it because of the global keyword? If so, 
> why can't there be a "magic" "global $_GET, $_POST, $_SESSION ..." set in 
> every function, for every superglobal, instead of the way it is handled 
> now? The thing i don't get is, why the superglobals behave differently 
> than "normal" global variables at all.
In a word: efficiency.

There's an expression: "Fast, Clean, Cheap: Pick Two".

The current implementation is Fast and Cheap, but as this thread has 
highlighted, it's not entirely clean.

> Ok, you have explained the technical reasons, but that's not what i mean. 
> For me as a php user (developing in php), the only difference should be, 
> that i don't have to use the global keyword. Everything else seems like a 
> bug or design flaw to me.
>
You won't hear a lot of argument from me.  I just care less that it is the 
way it is.

-Sara