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To: Nikita Popov <nikita.ppv@gmail.com>
CC: Nicolas Grekas <nicolas.grekas+php@gmail.com>, Mark Randall
	<marandall@php.net>, "internals@lists.php.net" <internals@lists.php.net>
Thread-Topic: [PHP-DEV] Re: [RFC] "use global functions/consts" statement
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Date: Sun, 26 Jan 2020 16:25:29 +0000
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Subject: Re: [PHP-DEV] Re: [RFC] "use global functions/consts" statement
From: tysonandre775@hotmail.com (tyson andre)

Hi internals,=0A=
=0A=
https://wiki.php.net/rfc/use_global_elements and the implementation has bee=
n updated again - the syntax is now declare(function_and_const_lookup=3D'gl=
obal')=0A=
with a literal string instead of a keyword.=0A=
The voting option for whether it was a string or a keyword was removed.=0A=
=0A=
I plan to move this to the voting phase on Monday, if nothing else needs to=
 be addressed=0A=
=0A=
> Saving two characters per file doesn't seem like a great motivation to ad=
d additional special cases to core language syntax.=0A=
> Right now, declare just types "identifier =3D expr", while with this chan=
ge it's going to be "identifier =3D (expr | a | few | extra | keywords)".=
=0A=
=0A=
Thinking about it again, I'd agree with the parsing special cases being inc=
onvenient.=0A=
=0A=
> So, most references are to classes outside the current namespace. The num=
ber of references to global classes and classes in the same namespace is ac=
tually pretty similar, there are 5% more global references.=0A=
> From that perspective, changing the name resolution rules to always look =
for the global symbol if unimported would actually slightly reduce the numb=
er of necessary "use" statements.=0A=
=0A=
It would be more understandable for new php developers familiar with other =
languages if name lookup was consistent across classes.=0A=
=0A=
I don't have as strong a use case for this as I do for eliminating the func=
tion/const ambiguity. Changing class resolution (via automated tool) would =
require more code changes than function/constant resolution, and the classe=
s are already unambiguous.=0A=
=0A=
> If we were to make such a change (hypothetically), the way I would view i=
t is "use new name resolution rules" or not, rather than a collection of fi=
ne-grained options.=0A=
> Notably Rust made a major change to how symbols are=0A=
> resolved in the 2018 edition, so=0A=
> such things aren't inconceivable, especially with the right tooling.=0A=
=0A=
If a setting affecting all name resolution was added, then forbidding the u=
se of both that new setting (e.g. <name_lookup=3Dglobal>) and declare(funct=
ion_and_const_lookup) in the same file would keep code simpler.=0A=
=0A=
If "use new name resolution rules" was the only option, the larger amount o=
f refactoring for class references (and doc comments) might discourage usin=
g the new name resolution for functions/constants, and make backporting pat=
ches to previous major versions of applications/libraries more error prone =
(e.g. \MyNS\Exception vs \Exception). The refactoring might also be perceiv=
ed as risky.=0A=
So I'd still want to see the voting results&feedback for function_and_const=
_lookup before investigating approaches to changing class resolution.=0A=
=0A=
Rust would also catch many more possible bugs in symbol resolution at compi=
le time.=0A=
The static analyzers for PHP can detect almost as many bugs, but would requ=
ire that people be aware of the analyzers, configure them, and use them in =
CI.=0A=
=0A=
- Code such as if (class_exists(SomeClass::class)) { /* Use SomeClass */ } =
might be permitted if analyzing class_exists conditionals is a feature of a=
 static analyzer.=0A=
=0A=
- Tyson=