Newsgroups: php.internals
Path: news.php.net
Xref: news.php.net php.internals:127638
Feedback-ID: i8414410d:Fastmail
Precedence: bulk
MIME-Version: 1.0
Date: Tue, 10 Jun 2025 15:09:28 -0500
To: "php internals" <internals@lists.php.net>
Message-ID: <e0406bea-b6e2-47bf-b5d6-f9fea4332c5d@app.fastmail.com>
In-Reply-To: 
 <CANTuiHsK+qfVEHE1EPSLp-KmZgqFKoOj28sEERWGhUjzh5dE-Q@mail.gmail.com>
References: 
 <CANTuiHsCi30ArpBqDnyUGt5M-RUVJ7trfF5+F0Vq9EeEVuty_g@mail.gmail.com>
 <f6b47389-b4cd-4f56-9016-ad8fcff4c413@app.fastmail.com>
 <CANTuiHsK+qfVEHE1EPSLp-KmZgqFKoOj28sEERWGhUjzh5dE-Q@mail.gmail.com>
Subject: Re: [PHP-DEV] Feature Discussion |
Content-Type: text/plain; charset=utf-8
Content-Transfer-Encoding: quoted-printable
From: larry@garfieldtech.com ("Larry Garfield")

On Tue, Jun 10, 2025, at 2:45 PM, Dmitry Derepko wrote:
> Thanks for participating, Larry.
>
> On Mon, Jun 9, 2025 at 10:29=E2=80=AFPM Larry Garfield <larry@garfield=
tech.com> wrote:
>> 2. Please link to a PR of your actual implementation.  In context it =
looks like your branch comparison link is to the version you said didn't=
 work, so it's not that helpful.
>
> Correct, I don't have another one. This is big feature, I need a lot o=
f=20
> time to implement it. I don't want to waste my time if we decide that=20
> RFC won't pass at all.

Understood.

>> 3. The biggest question that has come up in the past (Ilija and I hav=
e discussed it at length) is, naturally, autoloading.  How if at all do =
you address that?
>
> In the original message I mentioned `use extension` construction. This=20
> should be enough for solution, isn't it?

Very much not.  The `use` construct has no bearing on autoloading curren=
tly.  Autoloading happens only for classes and class-like things (interf=
aces, traits, enums).  If a function is not found, PHP just crashes.  Va=
rious solutions to this have been discussed over the years, none of whic=
h ever made it as far as a vote.

I toyed with the idea of having extension functions compile to a static =
method on a class as a way around this, but of course then you end up wi=
th a file-per-function, and the file name has to match not the function =
name, but whatever mangled class name gets generated.  Not at all intuit=
ive.

In fairness, I think with universal opcache, preloading, and the increas=
ing use of persistent processes, just skipping autoloading for functions=
 and front-loading them via composer.json's "files" block is fine for th=
e 80% case.  But it feels like I am in the minority on that position.

>> 4. The other big question was determining when to match a given "meth=
od" call to an extension function, when the type of a variable is not al=
ways known at compile time.  How did you address this?
>
> Cannot understand the passage, could you explain more?

<?php=20
// index.php

function Point.area(): int {=20
  return $this->x & $this->y;
}

function doStuff($p) {
  // At compile time, we don't know that $p is a Point. In fact, it may =
not be.
  // The function will allow any value here, even a non-object, so it do=
esn't know
  // if this should be compiled to Point__area($p) or left as is.
  print $p->area();
}

The only way I could think of to handle that is to have a method call "t=
rap" similar to class autoloading, that when hit checks at runtime "hey,=
 this method didn't exist, but is there a `use`d function that would mat=
ch based on the runtime type of this value?"  But Ilija felt that would =
be prohibitively slow.  It would certainly be slower than just a functio=
n/method call since the trap takes time.

And then we get into questions of inheritance, and, well, it gets even m=
essier fast.

One possibility that we riffed on during the pipes discussion (mostly of=
f list, I think) was using +> for some combination of extension function=
s and Elixir-style first-arg pipe passing, so that $p+>area() would sign=
al to the engine (compile time or runtime) that area() wasn't a method b=
ut a function that should get $p passed to it.  That would solve the "tr=
ap" problem, but still doesn't address autoloading, the lack of compile =
time type knowledge, or how to differentiate between Point.area(), Shape=
Interface.area(), Rect.area(), etc.

--Larry Garfield