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Date: Fri, 15 Sep 2017 19:41:25 +0200
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To: ilija.tovilo@me.com
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Subject: Re: [PHP-DEV] [RFC] Deprecate the extract function in PHP 7.3
From: ocramius@gmail.com (Marco Pivetta)

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Hi,

On 15 Sep 2017 19:37, <ilija.tovilo@me.com> wrote:

Hi Marco

I can see it=E2=80=99s usefulness in this case.

But wouldn=E2=80=99t it be better to implement this by hand in these rare c=
ases
(it=E2=80=99s 3 lines of code) instead of encouraging the pollution of the =
symbol
table by unknown input? It=E2=80=99s also clearer since people who don=E2=
=80=99t know the
`extract` function probably don=E2=80=99t expect it to mutate the local sym=
bol
table.

Cheers


On 15 Sep 2017, 19:26 +0200, Marco Pivetta <ocramius@gmail.com>, wrote:

Heya,

This is typically used in templating engines.
The one I worked on is
https://github.com/zendframework/zend-view/blob/
5523511b6771cb6c060a77f6777426526a8db5ab/src/Renderer/
PhpRenderer.php#L491-L492


Marco Pivetta

http://twitter.com/Ocramius

http://ocramius.github.com/

On Fri, Sep 15, 2017 at 7:20 PM, <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 deprecating=
 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 coul=
d 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?

Regards

Absolutely, can be replaced with a loop indeed.

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