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To: Nikita Popov <nikita.ppv@gmail.com>
CC: Claude Pache <claude.pache@gmail.com>, Nicolas Grekas
	<nicolas.grekas+php@gmail.com>, Mark Randall <marandall@php.net>,
	"internals@lists.php.net" <internals@lists.php.net>
Thread-Topic: [PHP-DEV] [RFC] "use global functions/consts" statement
Thread-Index: AQHV1IfBuqjWnIu9lEWrxlRKvYFij6f9dXecgADKhQCAAFMdqIAACCeAgAC7crk=
Date: Tue, 28 Jan 2020 02:36:45 +0000
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Subject: Re: [PHP-DEV] [RFC] "use global functions/consts" statement
From: tysonandre775@hotmail.com (tyson andre)

https://wiki.php.net/rfc/use_global_elements#implementation_details has bee=
n updated after the latest feedback.=0A=
The implementation was also updated.=0A=
=0A=
The opt-in `declare(function_and_const_lookup=3D'global')` directive=0A=
now only allows declaring a function or constant in a file if the same name=
 has been used=0A=
in an above statement with `use function MyNS\function_name;` or `use const=
 MyNS\MY_CONSTANT`.=0A=
If it was not used and the current namespace is not the global namespace, i=
t is a compilation error.=0A=
=0A=
This is more verbose, but makes certain types of bugs impossible to write,=
=0A=
and guarantees that the function being declared is the one being referred t=
o=0A=
in subsequent uses in the same block of code (e.g. after/within the "namesp=
ace MyNS" statement).=0A=
=0A=
Declarations of functions/constants are often in a few files that are separ=
ate from other files,=0A=
and there are several options to deal with the verbosity:=0A=
=0A=
1. Use =3D'global', or don't enable function_and_const_lookup in those file=
s.=0A=
2. Accept it and add all of the required uses=0A=
3. For constants, use define(). Not ideal, but still an option.=0A=
=0A=
I plan to move this to the voting phase on Tuesday if nothing else comes up=
.=0A=
=0A=
As an example of how edge cases would work:=0A=
=0A=
```=0A=
declare(function_and_const_lookup=3D'global')=0A=
namespace MyNS;=0A=
// Outside the global namespace, without 'use function MyNS\my_function;',=
=0A=
// declaring a function is a compile error when function_and_const_lookup=
=3D'global'.=0A=
use function MyNS\factorial;=0A=
use function MyNS\sprintf;=0A=
use const MyNS\MY_PREFIX;  // same for constants.=0A=
=0A=
const MY_PREFIX =3D 'Prefix';=0A=
function sprintf($msg, ...$args) {=0A=
    // this forces the implementation to explicitly refer to sprintf from t=
he global namespace.=0A=
    return \sprintf(MY_PREFIX . " $msg", ...$args);=0A=
}=0A=
function factorial(int $n) {=0A=
    return $n > 1 ? factorial($n - 1) * $n : 1;=0A=
}=0A=
if (version_compare(PHP_VERSION, '8.0.5') >=3D 0) {=0A=
    // ...=0A=
}=0A=
```=0A=
=0A=
Thanks,=0A=
- Tyson=