Newsgroups: php.internals
Path: news.php.net
Xref: news.php.net php.internals:104642
MIME-Version: 1.0
References: <a70baca7-f0af-49de-9cf9-5421e42e0a0c@www.fastmail.com>
In-Reply-To: <a70baca7-f0af-49de-9cf9-5421e42e0a0c@www.fastmail.com>
Date: Mon, 11 Mar 2019 00:47:04 +0100
Message-ID: <CAFPFaMLqGApz6N5Sg8TY9yir6c2=zBNDG2j0AUWHnRkxx9T3tw@mail.gmail.com>
To: Larry Garfield <larry@garfieldtech.com>
Cc: PHP internals <internals@lists.php.net>
Content-Type: multipart/alternative; boundary="000000000000809b0a0583c613b9"
Subject: Re: [PHP-DEV] RFC Draft: Comprehensions
From: george.banyard@gmail.com ("G. P. B.")

--000000000000809b0a0583c613b9
Content-Type: text/plain; charset="UTF-8"

On Sun, 10 Mar 2019 at 22:45, Larry Garfield <larry@garfieldtech.com> wrote:

> Hello, peoples.  I know it's been discussed once or twice before on the
> list, many years ago, but not recently.  I therefore feel OK putting forth
> the following draft proposal for Comprehensions, aka "compact generators",
> in PHP:
>
> https://wiki.php.net/rfc/comprehensions
>
> Sara Golemon has written a preliminary patch that is partially complete
> (see the RFC link for details, it's impressively simple), but unfortunately
> doesn't have the bandwidth to complete it at this time.  I am therefore
> looking for collaborators with more knowledge of internals than I (which is
> almost everyone) to help finish it up.
>
> The syntax proposed is also subject to revision if a terser but still
> lexer-friendly alternative can be proposed.
>
> At the moment I'm not calling this Proposed yet, as I don't feel
> comfortable doing so until someone else is on board to finish coding it.
> That said, if someone wants to weigh in on the concept for now (hopefully
> supportively) that's also fine.
>
> Anyone excited enough to help finish the job?
>
> (This is my first RFC collaboration, so if you're going to smack me for
> goofing something please be gentle about it.)
>
> --
>   Larry Garfield
>   larry@garfieldtech.com
>
> --
> PHP Internals - PHP Runtime Development Mailing List
> To unsubscribe, visit: http://www.php.net/unsub.php
>

Hello Larry,

I do like the proposal of adding comprehensions to PHP, and I do agree with
you
that short closures do not replace a short closure synstax (as even with
them it
is still not ideal). However I have a couple of complaints, JS
comprehensions have
not become a standard and have been removed from my understanding [1][2].

Secondly I don't really understand the argument for using `for` instead of `
foreach`
Sure it saves 4 chars but the PHP version compared to the Python uses `yield
`
which already lengthen it, I do understand why it is there because it is a
generator.
But Python using `for` makes more sense, imho, because its syntax is
`expression for item in iterator (if condition)`.
Now maybe what I am going to say is total BS because I don't know *how* the
engine
works, but wouldn't also use foreach make it easier for the lexer as it
already know the
`as` keyword?

Maybe if we want to mimic the Python syntax why not use a syntax like:
`(yield expression) foreach iterator as item (if condition)`

I also suppose that comprehension chaining is possible because it returns a
generator.

Small nitpick but shouldn't the `current` method link to the
Generator->current instead of
the function `current` which only works with arrays?

Also would it be possible to use a string as an iterable expression?
Because currently it's not possible to foreach a string (but that's maybe
more the scope
of another RFC).

Best regards

George P. Banyard

[1]
https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/Array_comprehensions
[2]
https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/Generator_comprehensions

--000000000000809b0a0583c613b9--