Newsgroups: php.internals
Path: news.php.net
Xref: news.php.net php.internals:118870
Message-ID: <6C17C72E-05D9-4543-B6FB-D86B4C14A2AE@koalephant.com>
Content-Type: multipart/alternative;
	boundary="Apple-Mail=_3423BD56-3EC7-4BB9-9631-52B302B1D239"
Mime-Version: 1.0 (Mac OS X Mail 16.0 \(3696.120.41.1.1\))
Date: Sun, 23 Oct 2022 20:57:33 +0700
In-Reply-To: <50321070-3682-c238-d8b4-3d0f6832c4bc@pouzenc.fr>
Cc: internals@lists.php.net
To: Ludovic Pouzenc <ludovic@pouzenc.fr>
References: <50321070-3682-c238-d8b4-3d0f6832c4bc@pouzenc.fr>
Subject: Re: [PHP-DEV] Newcomer, PHP pre-processing, Magic Constants __FILE__
 and __LINE__ override with #line like in C
From: php-lists@koalephant.com (Stephen Reay)

--Apple-Mail=_3423BD56-3EC7-4BB9-9631-52B302B1D239
Content-Transfer-Encoding: quoted-printable
Content-Type: text/plain;
	charset=utf-8



> On 23 Oct 2022, at 20:43, Ludovic Pouzenc <ludovic@pouzenc.fr> wrote:
>=20
> Hi,
>=20
> I'm a newcomer here. I came from https://wiki.php.net/rfc/howto.
>=20
> *TL;DR:* I want to know if a proposal of a #line parsing to alter =
__FILE__ and __LINE__ in PHP like it exists in C could be a good idea.
>=20
> I've searched about __LINE__ and __FILE__ in mailing archives and =
wiki, I don't really find things matching. I hope it's not because "__" =
are stripped before search. "Magic constants" didn't help neither. Let =
me know if I am rethinking and old thing already imagined here in the =
past.
>=20
> *Background / use case:* I think at first about webservices, maybe the =
useful also with browser/human-facing use cases.
>=20
> With PHP, it's hard to get high responsiveness under load if user code =
start by loading a composer's autoload.php, then (lazy) loads a whole =
framework with 10+ dependencies, then execute 1 SQL request, 1 =
json_encode() then output and exit. Even with "Slim" framework that =
should be minimal, using only the route feature, I see "strace" counting =
200+ file-related syscalls per request with recent =
linux/debian/apache/php-fpm.
>=20
> It's not so hard to get it better with other langages : when they are =
compiled, or when framework loading happens at server start and to at =
each request.
>=20
> Web projects have more and more a "compilation" phase for minimising =
JS, for proprocessing scss to css, it is possible to hook it some PHP =
processing too.
>=20
> In my university, I started using a purpose-written PHP Preprocessor =
to minimize runtime dependency loading. It only understands #include =
like in C. =46rom a src/mywebservice/v1/some-endpoint.php it will =
generate and build/mywebservice/v1/some-endpoint.php with all #include =
"some/path/somedep.php" replaced by the file's contents.
>=20
> So the generated some-endpoint.php have no run-time dependency at all: =
no autoload, no include(), no require(). I think it evens maximize the =
gains with APC caching.
>=20
> The preprocessor also generate things like #line 2 =
"some/path/somedep.php" where an #include was encountered, then a thing =
like #line 47 "src/mywebservice/v1/some-endpoint.php" right after the =
end of the inclusion. In C, a great concrete example of #line importance =
is working with a flex/bison parser generator.
>=20
> If PHP parser interpret #line as in C, __FILE__ and __LINE__ Magic =
Constants will be changed to source file and line, instead of generated =
file and line. It could greatly improve development write-then-rerun =
cycle. (missing ";" at line NN , other PHP Errors, Exception =
details/traces)
>=20
> I hope it could unlock many use cases where "big" PHP frameworks get =
really hard time to try to compete with other languages equivalents.
>=20
> Do you think it's an idea that is suitable to discuss, improve and =
submit as an RFC ?
>=20
> Regards,
>=20
> --=20
>=20
> Ludovic Pouzenc
> www.pouzenc.fr
>=20
> --=20
> PHP Internals - PHP Runtime Development Mailing List
> To unsubscribe, visit: https://www.php.net/unsub.php
>=20

Hi Ludovic,

I can=E2=80=99t comment much on the actual change in the parser you=E2=80=99=
re asking about, but it sounds to me like preloading =
(https://www.php.net/manual/en/opcache.preloading.php =
<https://www.php.net/manual/en/opcache.preloading.php>, introduced via =
https://wiki.php.net/rfc/preload <https://wiki.php.net/rfc/preload>) =
might be a workable solution that=E2=80=99s already available?


Cheers

Stephen=20=

--Apple-Mail=_3423BD56-3EC7-4BB9-9631-52B302B1D239--