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From: "Alfred M. Szmidt" <ams@gnu.org>
To: Stefan Monnier <monnier@iro.umontreal.ca>
Cc: jdtsmith@gmail.com, enometh@meer.net, emacs-devel@gnu.org
Subject: Re: Code for cond*
Date: Thu, 25 Jan 2024 11:12:52 -0500	[thread overview]
Message-ID: <E1rT2LU-0005nz-EK@fencepost.gnu.org> (raw)
In-Reply-To: <jwv34ulpfmk.fsf-monnier+emacs@gnu.org> (message from Stefan Monnier on Thu, 25 Jan 2024 11:05:16 -0500)


   >    (cond-let
   >      (:let var-for-rest value)
   >
   > Is there a reason why using a keyword here?

   It was to "ensure" compatibility with existing `cond` code.

I really hope we are not going to modify cond -- which has been
literally the same since it created many decades ago.  It would be
confusing to all Lisp programmers, even if it was backward compatible.

   Also it was based on the premise that most `cond`s would *not* use it
   since such code is mostly needed to replace things like:

       (let (val)
	 (cond
	  [...]
	  ((foo (setq var (bar)))
	   [...])
	  [...]))

   And while such code does occur, it occurs only in a minority of `cond`
   uses, so I thought it would be worthwhile for it to "stand out" so as
   not to catch the reader by surprise.

Are such cases really worth solving by extending cond, and not better
addressed in a different macro (cond*, pcase, ...) -- or even just
sticking to the status quo?  

The above "idiom" is much easier to understand since it just uses well
known Lisp behaviour than modifying cond even if it is really ugly
... the feature is a nice addition, but is it worth it?



  reply	other threads:[~2024-01-25 16:12 UTC|newest]

Thread overview: 134+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-01-18  3:37 Code for cond* Richard Stallman
2024-01-18  4:59 ` Emanuel Berg
2024-01-20  3:39   ` Richard Stallman
2024-01-24 12:37     ` Po Lu
2024-01-24 19:12     ` Alan Mackenzie
2024-01-27  3:35       ` Richard Stallman
2024-01-18 15:44 ` Andrea Corallo
2024-01-19 10:42   ` João Távora
2024-01-21  3:04     ` Richard Stallman
2024-01-21 20:05       ` Adam Porter
2024-01-22  5:32         ` tomas
2024-01-23 13:39         ` Richard Stallman
2024-01-24  6:02           ` Po Lu
2024-01-24  9:48       ` Stefan Kangas
2024-01-24 10:09         ` Emanuel Berg
2024-01-24 11:30         ` João Távora
2024-01-24 12:08           ` João Távora
2024-01-24 12:09         ` Po Lu
2024-01-24 12:22           ` Ihor Radchenko
2024-01-24 12:33             ` Po Lu
2024-01-24 13:34               ` Ihor Radchenko
2024-01-24 13:52                 ` João Távora
2024-01-24 14:31                   ` Po Lu
2024-01-27  3:35                   ` Richard Stallman
2024-01-27  3:35                   ` Richard Stallman
2024-01-24 14:07                 ` Po Lu
2024-01-24 14:20                   ` Ihor Radchenko
2024-01-24 14:34                     ` Po Lu
2024-01-24 14:44                       ` Ihor Radchenko
2024-01-24 14:47                         ` João Távora
2024-01-24 15:28                         ` Emanuel Berg
2024-01-24 16:30                           ` Ihor Radchenko
2024-01-24 16:34                             ` Emanuel Berg
2024-01-25  9:06                           ` Po Lu
2024-01-25  9:55                             ` Alfred M. Szmidt
2024-01-25 10:38                               ` Eli Zaretskii
2024-01-25 11:29                               ` Po Lu
2024-01-25 12:04                                 ` Emanuel Berg
2024-01-25 13:32                                   ` Po Lu
2024-01-25 14:08                                     ` Emanuel Berg
2024-01-25 13:19                                 ` Alfred M. Szmidt
2024-01-25 13:43                                   ` Emanuel Berg
2024-01-25 14:31                                     ` Eli Zaretskii
2024-01-25 15:02                                       ` Emanuel Berg
2024-01-25 15:29                                         ` Eli Zaretskii
2024-01-25 15:33                                           ` Alfred M. Szmidt
2024-01-25 15:50                                             ` Eli Zaretskii
2024-01-25 16:01                                               ` Alfred M. Szmidt
2024-01-25 16:13                                                 ` Eli Zaretskii
2024-01-25 15:40                                           ` Emanuel Berg
2024-01-25 10:30                             ` Eli Zaretskii
2024-01-25 11:27                               ` Emanuel Berg
2024-01-24 12:15         ` Alan Mackenzie
2024-01-24 12:28           ` Emanuel Berg
2024-01-25  9:10           ` Po Lu
2024-01-25 11:56             ` Emanuel Berg
2024-01-25 13:21               ` Po Lu
2024-01-25 13:56                 ` Emanuel Berg
2024-01-25 23:32           ` Stefan Kangas
2024-01-20  3:39   ` Richard Stallman
2024-01-23 18:10 ` Stefan Monnier via Emacs development discussions.
2024-01-24  4:49   ` JD Smith
2024-01-24  9:45     ` Stefan Kangas
2024-01-24 15:29       ` JD Smith
2024-01-24 15:55         ` Stefan Monnier
2024-01-24 16:02           ` Stefan Monnier
2024-01-24 16:20           ` JD Smith
2024-01-24 17:08             ` Stefan Monnier
2024-01-24 16:35           ` [External] : " Drew Adams
2024-01-24 16:30     ` Drew Adams
2024-02-01  8:56       ` Madhu
2024-02-01 22:46         ` Emanuel Berg
2024-01-25  3:16     ` Madhu
2024-01-25 13:57       ` Stefan Monnier
2024-01-25 15:17         ` JD Smith
2024-01-25 15:37           ` JD Smith
2024-01-25 15:44             ` Alfred M. Szmidt
2024-01-25 16:00               ` JD Smith
2024-01-25 16:05               ` Stefan Monnier
2024-01-25 16:12                 ` Alfred M. Szmidt [this message]
2024-01-25 16:20                   ` Stefan Monnier
2024-01-25 16:33                   ` JD Smith
2024-01-29  3:19             ` Richard Stallman
2024-01-26  4:30   ` Richard Stallman
2024-01-28  3:06     ` Stefan Monnier via Emacs development discussions.
2024-01-30  3:59       ` Richard Stallman
2024-01-30 13:02         ` Stefan Monnier
2024-02-23  3:04           ` Richard Stallman
2024-01-26  4:30   ` Richard Stallman
2024-01-28  4:16     ` Stefan Monnier via Emacs development discussions.
2024-01-31  3:32       ` Richard Stallman
2024-01-31 13:20         ` Stefan Monnier
2024-02-03  3:32           ` Richard Stallman
2024-02-03  6:09             ` Stefan Monnier
2024-02-03  6:48               ` Emanuel Berg
2024-02-04  4:46               ` Richard Stallman
2024-02-04 14:04                 ` Stefan Monnier
2024-02-04  4:46               ` Richard Stallman
2024-02-04 13:58                 ` Stefan Monnier
2024-02-13  0:48                 ` Stefan Monnier
2024-02-13  2:27                   ` Stefan Monnier
2024-02-14 11:16                   ` Richard Stallman
2024-02-14 12:45                     ` Stefan Monnier
2024-02-22  3:05                       ` Richard Stallman
2024-02-22  4:08                         ` Stefan Monnier
2024-02-25  3:14                           ` Richard Stallman
2024-02-25 15:03                             ` Stefan Monnier
2024-02-29  3:50                               ` Richard Stallman
2024-02-29 18:07                                 ` Stefan Monnier
2024-02-29  3:50                               ` Richard Stallman
2024-02-13  0:41         ` Stefan Monnier
2024-02-23  3:04           ` Richard Stallman
2024-02-23 13:39             ` Stefan Monnier
2024-02-25  3:16               ` Richard Stallman
2024-02-25 14:57                 ` Alfred M. Szmidt
2024-02-25 15:38                   ` Stefan Monnier
2024-02-25 16:42                     ` Alfred M. Szmidt
2024-02-25 17:13                       ` Stefan Monnier
2024-02-25 17:22                     ` Alan Mackenzie
2024-02-25 17:46                       ` Alfred M. Szmidt
2024-02-25 18:13                         ` Stefan Monnier
2024-02-25 17:10                 ` Stefan Monnier
2024-02-27  3:11                   ` Richard Stallman
2024-01-24 12:39 ` Alan Mackenzie
2024-01-24 14:43   ` Emanuel Berg
2024-01-24 16:25   ` Manuel Giraud via Emacs development discussions.
2024-01-25 14:01   ` Code for cond* - cond*-match, cond*-subpat and backtrack-aliases Alan Mackenzie
2024-01-29  3:19     ` Richard Stallman
2024-01-29 12:16       ` JD Smith
2024-02-01  3:51         ` Richard Stallman
2024-02-01 14:54           ` JD Smith
2024-02-04  4:42             ` Richard Stallman
2024-01-29  3:19     ` Richard Stallman
2024-01-29  8:54       ` Andreas Schwab

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