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Date: Thu, 3 Sep 2020 16:08:13 -0400
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To: Sara Golemon <pollita@php.net>
Cc: David Rodrigues <david.proweb@gmail.com>, PHP internals <internals@lists.php.net>
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Subject: Re: [PHP-DEV] Draft RFC: foreach iteration of keys without values
From: chasepeeler@gmail.com (Chase Peeler)

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On Thu, Sep 3, 2020 at 12:05 PM Sara Golemon <pollita@php.net> wrote:

> On Thu, Sep 3, 2020 at 10:35 AM David Rodrigues <david.proweb@gmail.com>
> wrote:
>
> > Do you think that it could be proxied? I mean, optimize foreach
> > (array_keys()...) syntax to not call array_keys() in fact, but a
> optimized
> > version of foreach to handle key only. I don't know it opcache could do
> > that, and if it already does.
> >
> >
> I wouldn't use the word "proxied", but yes. In my mind the compiler would
> see:
>
> foreach(\array_keys($arr) as $key) {
>
> and quietly transform that into:
>
> foreach ($arr as $key => $_unusedVariableNameThatIsntEvenSpilledToTheScope)
> {
>
>
Are there other instances where we have optimizations like this? If so, are
they documented?

In terms of readability, I'm more likely to do
  $keys = array_keys($array);
  foreach($keys as $key){

That would obviously break the optimization we're talking about though.
Which makes me wonder if there are other places like that.


> Thus not iterating the array twice and creating a temporary array of key
> names.
>
> -Sara
>



-- 
Chase Peeler
chasepeeler@gmail.com

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