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Subject: Re: [PHP-DEV] Unsetting loop variables at the end of the loop
From: mwacker@cornellsun.com (Mike Wacker)

Rasmus Lerdorf wrote:
> We can't just randomly reset variables based on their scope in this one
> specific case.  If we are going to "fix" this, it should be done by
> introducing a way to do proper local scope variables.  Resetting a
> reference simply because it is convenient in this one case would be
> completely inconsistent.
> 
> -Rasmus

I have some thoughts on this for PHP 6, but here's something else that 
might be worth looking into.

When you write [foreach ($ii as $i) ...], you usually expect that $i is 
not a reference variable (you would have used &$i otherwise).  However, 
PHP allows this even if $i is already a reference variable (e.g.: it was 
used as such in a previous loop).

Now look at this code:

function f(&$x) {
   echo $x;
}
$x = 1;
$args = array($x);
call_user_func_array('f', $args);

In PHP 5.3, this would trigger a warning and cause $x to be NULL inside 
of f because you mixed value and reference types in an improper way.

This foreach() issue is essentially being caused by a similar evil mix 
of reference and value types.  Perhaps [foreach ($ii as $i)] should 
trigger a warning if $i already exists as a reference variable.