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Date: Fri, 15 Sep 2017 11:52:51 -0600
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To: ilija.tovilo@me.com
Cc: PHP internals <internals@lists.php.net>
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Subject: Re: [PHP-DEV] [RFC] Deprecate the extract function in PHP 7.3
From: derokorian@gmail.com (Ryan Pallas)

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On Fri, Sep 15, 2017 at 11:38 AM, <ilija.tovilo@me.com> wrote:

> Hi Ryan
>
> I can see your argument. The reasoning behind it is that a function in th=
e
> standard library should not encourage unsafe code. Admittedly, since this
> function is rarely used except for templating systems one could call this=
 a
> non-issue. I just wanted to bring it up.
>

That makes sense. What about performance difference? On a reasonable sized
array (not 10k items and not 2) which is faster?

extract($array);

- or -

foreach ($array as $key =3D> $value)
    $$key =3D $value;

Honestly, I don't know (ps 2 lines without braces instead of 3!)


>
> Regards
>
>
> On 15 Sep 2017, 19:30 +0200, Ryan Pallas <derokorian@gmail.com>, wrote:
>
>
>
> On Sep 15, 2017 11:22 AM, <ilija.tovilo@me.com> wrote:
>
> Hi!
>
> The `extract` function takes an associative array and puts it into the
> local symbol table.
> http://php.net/manual/en/function.extract.php
>
> ```
> $array =3D [
>     =E2=80=98foo=E2=80=99 =3D> =E2=80=98foo=E2=80=99,
>     =E2=80=98bar=E2=80=99 =3D> =E2=80=98bar=E2=80=99,
> ];
>
> extract($array);
>
> print $foo; // "foo"
> ```
>
> As a second parameter the `extract` function takes some options to make
> this function less dangerous, like `EXTR_SKIP` that prevents an existing
> local variable of being overwritten. There=E2=80=99s a few more options, =
go ahead
> and take a look at the documentation. `EXTR_OVERWRITE` is the default one
> though. You can also pass a prefix for the variable names as a third
> argument.
>
> I seriously doubt the usefulness of this function, especially looking at
> the potential risks. The fact that overwriting the local variables is the
> default behaviour doesn=E2=80=99t make it any better. I suggest deprecati=
ng it in
> PHP 7.3 and removing it in 8.
>
> In a whole Symfony-Stack (3.4) with all of it=E2=80=99s dependencies I co=
uld only
> find two usages of this function, both of which could be easily rewritten
> in vanilla PHP:
> https://github.com/symfony/symfony/blob/master/src/Symfony/
> Component/Templating/PhpEngine.php#L148
> https://github.com/symfony/symfony/blob/master/src/Symfony/
> Component/Templating/PhpEngine.php#L158
>
> Only downside: A polyfill is probably impossible since you cannot mutate
> the local symbol table of the callee (as far as I=E2=80=99m aware).
>
> Any thoughts?
>
>
> I see no gain by removing this function. I've also seen it used for
> templating quite often. Yes the functionality could be changed not to use
> extract and end up working the same to the consumer but why make people
> rewrite these things for no apparent gain (and likely a small performance
> hit)?
>
>
> Regards
>
>
>
>

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