Newsgroups: php.internals
Path: news.php.net
Xref: news.php.net php.internals:110710
Content-Type: text/plain;
	charset=utf-8
Mime-Version: 1.0 (Mac OS X Mail 13.4 \(3608.80.23.2.2\))
In-Reply-To: <CAF+90c9ow-_=DSZ9LFhKzA1ZgHcf0LPt-p7tnhKRcgVUBnLfZw@mail.gmail.com>
Date: Tue, 23 Jun 2020 19:45:18 +0200
Cc: PHP internals <internals@lists.php.net>
Content-Transfer-Encoding: quoted-printable
Message-ID: <E0732EB9-8B22-4E57-8169-4D1B00C231D6@gmail.com>
References: <CAF+90c9ow-_=DSZ9LFhKzA1ZgHcf0LPt-p7tnhKRcgVUBnLfZw@mail.gmail.com>
To: Nikita Popov <nikita.ppv@gmail.com>
Subject: Re: [PHP-DEV] [RFC] Treat namespaced names as single token, relax
 reserved keyword restrictions
From: claude.pache@gmail.com (Claude Pache)


> Le 16 juin 2020 =C3=A0 10:52, Nikita Popov <nikita.ppv@gmail.com> a =
=C3=A9crit :
>=20
> Hi internals,
>=20
> Inspired by the recent discussion on reserved keyword reservation, I'd =
like
> to propose the following RFC:
>=20
> https://wiki.php.net/rfc/namespaced_names_as_token
>=20
> This RFC makes two related changes: Treat namespaced names as a single
> token, which enables use of reserved keywords inside them. And remove
> reserved keyword restrictions from various declarations.
>=20
> The RFC comes with a small backwards compatibility break related to =
names
> that include whitespace, but will hopefully reduce the backwards
> compatibility impact of future reserved keyword additions.
>=20
> Regards,
> Nikita

In fact, for classes and namespaces, we can probably do better, namely =
we can lift almost all keyword restriction, not only in definition and =
declaration, but also in in use.

Indeed, bare names of class (and trait, interface, etc) and namespace =
can appear only in few, well-defined positions, where it cannot be =
confused with a keyword, namely:

* after a handful of keywords: `new yield`, `class yield`, `instanceof =
yield`, `use yield`, `use foo as yield`, etc.
* before a paamayim nekudotayim: `yield::$foo`, `yield::foo()`, =
`yield::FOO`;
* before a backslash: `yield\foo`.

As far as I can see, the only keywords that can legally appear in those =
positions (and therefore must remain unavailable) are: `namespace` =
(because of namespace-relative names: `namespace\foo`), and `class` =
(because of anonymous classes: `new class { }`.

(As for functions and constants, I=E2=80=99m still thinking that it is =
not a good idea to allow to define or import a symbol that cannot be =
used. You will make the life of few library maintainers a little easier, =
but you will make the life of many users a little harder.)

=E2=80=94Claude