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From: Eric Abrahamsen <eric@ericabrahamsen.net>
To: monnier@iro.umontreal.ca
Cc: emacs-devel@gnu.org
Subject: Re: Make peg.el a built-in library?
Date: Sun, 19 Sep 2021 08:25:57 -0700	[thread overview]
Message-ID: <87zgs8ege2.fsf@ericabrahamsen.net> (raw)
In-Reply-To: <875yvafjr9.fsf@ericabrahamsen.net> (Eric Abrahamsen's message of "Wed, 08 Sep 2021 21:36:10 -0700")

Bumping this up in case it slid off radars: I'd like to at least push
the documentation patch to peg.el...

On 09/08/21 21:36 PM, Eric Abrahamsen wrote:
> On 08/26/21 08:34 AM, Eric Abrahamsen wrote:
>> Eli Zaretskii <eliz@gnu.org> writes:
>>
>>>> From: Eric Abrahamsen <eric@ericabrahamsen.net>
>>>> Date: Wed, 25 Aug 2021 11:52:00 -0700
>>>> Cc: Stefan Monnier <monnier@iro.umontreal.ca>
>>>> 
>>>> In my on-again-off-again quest to not have to write text parsers myself,
>>>> I was pointed towards the PEG library (in ELPA), which does pretty much
>>>> exactly what I want (Parsing Expression Grammars).
>>>> 
>>>> Would the maintainers consider moving this into Emacs proper? I ask
>>>> mostly because this would be very useful to have in Gnus, both to
>>>> replace the home-made parser in gnus-search.el, and I would hope to
>>>> parse eg IMAP server responses more fully and reliably.
>>>
>>> Fine with me, but please update the (outdated) Wiki page to say where
>>> the latest peg.el is, when it is imported.
>>
>> Will do. Stefan also asked me to make sure the library actually does
>> what I expect it to do, before making this move, so I'll write the code
>> first.
>
> Okay, I wrote some code: the "use-peg-in-gnus-search.diff" attachment is
> the result of that. It works really well! A net removal of ~100 LOC
> (obviously we're still in deficit with the addition of peg.el), it
> already fixes some wrong behavior of the old parser, and it's much
> easier to reason about and add new behavior to. It's the shiny
> declarative future I was looking forward to.
>
> Whether or not PEG gets added to core I'd like to propose some patches.
> The "peg-doc-patches.diff" attachment adds some documentation to the
> Commentary section, including an example grammar based on a
> much-simplified version of what gnus-search does.
>
> The peg-allow-symbols patch is more tentative. The issue is that _all_
> of the entry-points to peg code are macros, meaning you can't build your
> grammar up in a variable, and then pass that variable to any of
> `peg-run', `peg-parse', `with-peg-rules', etc. Nobody will evaluate the
> variable; you have to literally write the rules inside the
> `with-peg-rules' form. It seems like a fairly plausible use-case to
> store the rules in a variable or an option, even if you're not doing
> run-time manipulation of them. The only solution, as Adam found with
> org-ql, is to `eval' one of the macros.
>
> This doesn't seem necessary! The patch has `with-peg-rules' check if the
> rules are a symbol, and take the `symbol-value' if so. But I wonder if
> it wouldn't be nicer to break some of the code out: `peg-normalize'
> seems to be the entry-point for "compile this grammar", and that could
> be modified to work the way that some languages provide for pre-compiled
> regexps: a way to let the developer build and compile the grammar at
> load-time or launch-time, then feed the stored compiled version to
> parsing routines.
>
> `peg-parse' could be a function, or maybe it also could also just check
> if its argument is a symbol.
>
> I hope someone will have some thoughts on this!
>
> Eric



  reply	other threads:[~2021-09-19 15:25 UTC|newest]

Thread overview: 100+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-08-25 18:52 Make peg.el a built-in library? Eric Abrahamsen
2021-08-26  6:17 ` Eli Zaretskii
2021-08-26 15:34   ` Eric Abrahamsen
2021-09-09  4:36     ` Eric Abrahamsen
2021-09-19 15:25       ` Eric Abrahamsen [this message]
2021-09-30 19:44       ` Stefan Monnier
2021-09-30 20:34         ` Adam Porter
2021-10-01  8:14           ` Augusto Stoffel
2021-10-01 18:05           ` Stefan Monnier
2021-10-01 18:40             ` Eric Abrahamsen
2021-10-02  3:57               ` Stefan Monnier
2021-10-02  7:32             ` Adam Porter
2021-10-02 14:45               ` Stefan Monnier
2021-10-02 15:13                 ` Adam Porter
2021-08-26 17:02 ` Adam Porter
2021-08-26 17:25   ` Eric Abrahamsen
2021-08-27  3:17   ` Eric Abrahamsen
2021-08-27  6:41     ` Helmut Eller
2021-08-27 16:57       ` Eric Abrahamsen
2021-09-26 10:59       ` Augusto Stoffel
2021-09-26 15:06         ` Eric Abrahamsen
2021-09-26 18:36           ` Augusto Stoffel
2021-09-27 16:18             ` Eric Abrahamsen
2021-09-27 22:34         ` Richard Stallman
2021-09-28  3:52           ` Eric Abrahamsen
2021-09-28  8:09             ` tomas
2021-09-28  9:32               ` Helmut Eller
2021-09-28 10:45                 ` tomas
2021-09-28 15:24               ` Augusto Stoffel
2021-09-30  6:04             ` Richard Stallman
2021-10-01  3:27               ` Eric Abrahamsen
2021-10-09  1:31 ` Michael Heerdegen
2021-10-09  5:28   ` Michael Heerdegen
2021-10-09  8:12     ` Helmut Eller
2021-10-09 12:52       ` Stefan Monnier
2021-10-10  5:49         ` Helmut Eller
2021-10-14 10:25       ` Michael Heerdegen
2021-10-09 12:54   ` Stefan Monnier
2021-10-09 16:47     ` Eric Abrahamsen
2021-10-10  4:20       ` Michael Heerdegen
2021-10-10 21:40         ` Eric Abrahamsen
2021-10-13  2:58           ` Michael Heerdegen
2021-10-09 16:49   ` Eric Abrahamsen
2021-10-10  3:43     ` Stefan Monnier
2021-10-10  4:46       ` Michael Heerdegen
2021-10-10  5:58         ` Helmut Eller
2021-10-10 13:56           ` Stefan Monnier
2021-10-22 16:33           ` Michael Heerdegen
2021-10-31 23:43           ` Michael Heerdegen
2021-11-15 23:16             ` Michael Heerdegen
2022-11-07  3:33 ` Ihor Radchenko
2022-11-07 19:46   ` Eric Abrahamsen
2022-11-08  6:57     ` Helmut Eller
2022-11-08  8:51       ` Ihor Radchenko
2022-11-10  4:04       ` Richard Stallman
2022-11-10  5:25         ` tomas
2022-11-10  8:15           ` Eli Zaretskii
2022-11-10  8:29             ` tomas
2022-11-11  4:36           ` Richard Stallman
2022-11-08  8:47     ` Ihor Radchenko
2022-11-08 16:18       ` Eric Abrahamsen
2022-11-08 19:08         ` tomas
2022-11-08 19:42           ` Eric Abrahamsen
2022-11-16  4:27             ` [PATCH] " Eric Abrahamsen
2022-11-16  5:07               ` tomas
2022-11-16  5:39                 ` Eric Abrahamsen
2022-11-16 15:53                   ` tomas
2022-11-16  6:24               ` Ihor Radchenko
2022-11-16 18:15                 ` Eric Abrahamsen
2022-11-17 12:21                   ` Ihor Radchenko
2022-11-27  1:46                     ` Eric Abrahamsen
2022-11-27  8:57                       ` Eli Zaretskii
2022-11-28  1:09                         ` Eric Abrahamsen
2022-11-28 12:16                           ` Eli Zaretskii
2023-09-25  1:30                             ` Eric Abrahamsen
2023-09-25  2:27                               ` Adam Porter
2023-09-25 13:00                                 ` Alexander Adolf
2024-03-24 14:19                               ` Ihor Radchenko
2024-03-24 15:32                                 ` Eli Zaretskii
2024-03-25  1:45                                   ` Eric Abrahamsen
2023-01-11  7:39               ` Michael Heerdegen
2023-01-11  8:04                 ` Ihor Radchenko
2023-01-11 11:01                   ` Michael Heerdegen
2023-01-11 11:32                     ` tomas
2023-02-05 12:10                     ` Ihor Radchenko
2023-02-05 15:41                       ` Eduardo Ochs
2023-02-05 15:45                         ` Ihor Radchenko
2023-02-05 16:19                           ` Eduardo Ochs
2023-02-05 16:50                             ` Ihor Radchenko
2023-02-09  5:44                         ` Jean Louis
2023-02-06  0:33                       ` Michael Heerdegen
2022-11-08 14:01     ` Stefan Monnier
2022-11-08 14:42       ` tomas
2022-11-08 15:08       ` Visuwesh
2022-11-08 16:29         ` Juanma Barranquero
2022-12-02 20:20           ` Augusto Stoffel
2022-11-08 16:10       ` Eric Abrahamsen
2022-11-08 18:59         ` tomas
2022-11-08 19:42           ` Eric Abrahamsen
2022-11-08 22:03             ` Tim Cross

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