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Date: Thu, 13 Aug 2020 15:52:39 +0200
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To: Luis - SoftSAT Sistemas <luis@softsatsistemas.com.br>
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Subject: Re: [PHP-DEV] Nested functions
From: claude.pache@gmail.com (Claude Pache)

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> Le 12 ao=C3=BBt 2020 =C3=A0 22:05, Luis - SoftSAT Sistemas =
<luis@softsatsistemas.com.br> a =C3=A9crit :
>=20
>>>  Le 12 ao=C3=BBt 2020 =C3=A0 20:19, Luis - SoftSAT Sistemas =
<luis@softsatsistemas.com.br> a =C3=A9crit :
>>>=20
>>>  In the effort to make PHP a better language i want to ask why not =
"fix" nested functions as suggested in =
(https://wiki.php.net/rfc/true-nested-function-support) or block their =
usage?
>>>  The current behavior is a lot unexpected.
>>>=20
>>>  I am new here, sorry if it was already discussed, i can't find a =
good way to search the mailing history.
>>=20
>> Hi,
>>=20
>> Defining a global function inside another function is not useless. =
Here is a dummy example:
>>=20
>> ```php
>> // a.php
>> spl_autoload_register(function ($classname) {
>>     if ($classname =3D=3D=3D 'Foo\\B')
>>         require 'foo/b.php';
>> })
>>=20
>> // foo/b.php
>> namespace Foo;
>>=20
>> class B {
>>     // ...
>> }
>>=20
>> function some_helper(....$args) {
>>     // ...
>> }
>> ```
>>=20
>> The global function `Foo\some_helper` is defined inside the function =
used as autoloader.
>>=20
>> Also, from the RFC:
>>=20
>>>  They exist in the global namespace.
>>=20
>> I think you meant =E2=80=9CThey exist in the global scope=E2=80=9D? =
because they are defined in the namespace corresponding to the eventual =
`namespace` declaration of the file.
>>=20
>> =E2=80=94Claude
>=20
> You are right Claude, i wasn't thinking about this use case.
>=20
> But outside of this use case more problems arise.
> If `foo/b.php`  have some global variable and some function that use =
it the function breaks because the global variable will be "included" =
into current scope, while the functions into namespace scope.
> ```php
> //a.php
> function foo() {
>    require 'b.php';
>    //var_dump($something);
> }
>=20
> foo();
>=20
> var_dump(bar());
>=20
> //b.php
> $something =3D 10;
>=20
> function bar() {
>    global $something;
>    return $something;
> }
> ```
> I expected the `var_dump(bar());` output to be `int (10)`, but it was =
`NULL`, while if i do `var_dump($something);` from `foo()` it outputs =
`int(10)` as "normally expected".
> Given that "bar()" are at namespace scope, this can be "fixed" =
changing `$something =3D 10;` to `$GLOBALS['something'] =3D 10;`, but =
that doesn't change the fact that this behavior are odd and not =
intuitive.
>=20
> PS: I known that global variables are a bad thing, it was just an =
example.
>=20
> Anyway now i see that changing this will break the auto loader system.
>=20
> About the RFC you are right, they are wrong about the scope, but the =
RFC aren't mine, i just found it while searching about the subject.
>=20
> --L. Henrique

About global variables; it is an issue I encountered once upon a time =
when refactoring code. The short term solution is to declare the global =
variables both in the inner and the outer scope:

```php
// b.php
global $something;

$something =3D 10;

function bar() {
   global $something;
   return $something;
}
```

Functions in PHP have the following characteristics: they are defined =
globally, and they don=E2=80=99t inherit variables from their parent =
scope. On the other hand, anonymous functions (closures) are available =
locally, and they may import variables from their parent scope. Both =
sort of functions have their usages.

About the RFC page: It looks to me like an old abandoned stub. It =
isn=E2=80=99t even listed on https://wiki.php.net/rfc =
<https://wiki.php.net/rfc>=20

=E2=80=94Claude=

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