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From: Jim Porter <jporterbugs@gmail.com>
To: Eli Zaretskii <eliz@gnu.org>, Stefan Monnier <monnier@iro.umontreal.ca>
Cc: larsi@gnus.org, 52063@debbugs.gnu.org
Subject: bug#52063: 28.0.60; Confusing presentation of lambda
Date: Wed, 24 Nov 2021 14:33:22 -0800	[thread overview]
Message-ID: <9a8c985a-7042-a81c-5bf0-5117982c9cdc@gmail.com> (raw)
In-Reply-To: <83r1b571mc.fsf@gnu.org>

On 11/24/2021 12:14 PM, Eli Zaretskii wrote:
> I look at the values to make sure they are what I expect.  It's normal
> in Emacs to do that, isn't it?

I think in cases like that, it's useful to see the closure, since that's 
information that can help the user debug a problem. For example, if I 
have something like the following, it's helpful to see information about 
the closure:

   (let ((foo 1))
     (add-hook 'prog-mode-hook (lambda () (setq foo 1))))

In that case, the value of prog-mode-hook is:

   ((closure ((foo . 1) t) nil (setq foo 1)))

This is a contrived example, but similar sorts of things crop up in the 
real world. If the above example were significantly more complex (e.g. 
the `let' and the `add-hook' were in different functions), I might not 
realize that `foo' was lexically-bound unless I looked at the value of 
`prog-mode-hook' and saw the closure.

As such, I think the current behavior is better than simply showing what 
the user typed, i.e. "(lambda () ...)". That doesn't show the variables 
bound by the closure. However, the specific representation of the 
closure object could use some improvement. For example, I don't know 
what purpose the `t' and `nil' serve, although I'm sure both are useful 
to experts in some situations. Is there a way to represent all this 
information in a way that's easy for users to understand without 
expecting them to know the details of how closures are implemented in Emacs?





  parent reply	other threads:[~2021-11-24 22:33 UTC|newest]

Thread overview: 55+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-11-23 18:56 bug#52063: 28.0.60; Confusing presentation of lambda Eli Zaretskii
2021-11-24  7:35 ` Lars Ingebrigtsen
2021-11-24 12:48   ` Eli Zaretskii
2021-11-24 12:51     ` Lars Ingebrigtsen
2021-11-24 13:15       ` Eli Zaretskii
2021-11-24 13:31         ` Lars Ingebrigtsen
2021-11-24 14:38           ` Eli Zaretskii
2021-11-24 16:21             ` Lars Ingebrigtsen
2021-11-24 16:33               ` Stefan Monnier via Bug reports for GNU Emacs, the Swiss army knife of text editors
2021-11-24 16:54                 ` Eli Zaretskii
2021-11-24 17:19                   ` Stefan Monnier via Bug reports for GNU Emacs, the Swiss army knife of text editors
2021-11-24 17:44                     ` Eli Zaretskii
2021-11-24 19:06                       ` Stefan Monnier via Bug reports for GNU Emacs, the Swiss army knife of text editors
2021-11-24 19:53                         ` Eli Zaretskii
2021-11-24 20:08                           ` Stefan Monnier via Bug reports for GNU Emacs, the Swiss army knife of text editors
2021-11-24 20:14                             ` Eli Zaretskii
2021-11-24 22:02                               ` Stefan Monnier via Bug reports for GNU Emacs, the Swiss army knife of text editors
2021-11-24 22:33                               ` Jim Porter [this message]
2021-11-24 22:42                                 ` Jim Porter
2021-11-24 21:10                             ` Eduardo Ochs
2021-11-24 16:40             ` Filipp Gunbin
2021-11-24 16:54               ` Stefan Monnier via Bug reports for GNU Emacs, the Swiss army knife of text editors
2021-11-24 18:18                 ` Filipp Gunbin
2021-11-24 19:08                   ` Stefan Monnier via Bug reports for GNU Emacs, the Swiss army knife of text editors
2021-11-24 19:41                     ` Eli Zaretskii
2021-11-24 19:46                       ` Stefan Monnier via Bug reports for GNU Emacs, the Swiss army knife of text editors
2021-11-24 19:59                         ` Eli Zaretskii
2021-11-24 20:23                           ` Stefan Monnier via Bug reports for GNU Emacs, the Swiss army knife of text editors
2021-11-24 22:37                             ` Gregory Heytings
2021-11-25  0:09                               ` Filipp Gunbin
2021-11-25  8:57                               ` Michael Heerdegen
2021-11-25 13:09                                 ` Lars Ingebrigtsen
2021-11-25 14:08                                   ` Michael Heerdegen
2021-11-25 14:39                                   ` Gregory Heytings
2021-11-24 20:16                     ` Philipp Stephani
2021-11-24 21:44                       ` Stefan Monnier via Bug reports for GNU Emacs, the Swiss army knife of text editors
2021-11-25  0:13                       ` Filipp Gunbin
2021-11-25 13:15                         ` Lars Ingebrigtsen
2021-11-25 19:07                           ` Stefan Monnier via Bug reports for GNU Emacs, the Swiss army knife of text editors
2021-11-25 19:56                             ` Jim Porter
2021-11-26 12:28                               ` Lars Ingebrigtsen
2021-11-26 12:26                             ` Lars Ingebrigtsen
2021-11-26 13:13                               ` Stefan Monnier via Bug reports for GNU Emacs, the Swiss army knife of text editors
2021-11-26 13:22                                 ` Lars Ingebrigtsen
2021-11-26 13:26                                   ` Lars Ingebrigtsen
2021-11-26 14:57                                     ` Stefan Monnier via Bug reports for GNU Emacs, the Swiss army knife of text editors
2021-11-26 15:00                                       ` Lars Ingebrigtsen
2021-11-26 16:58                                         ` Stefan Monnier via Bug reports for GNU Emacs, the Swiss army knife of text editors
2021-11-27 14:17                                           ` Lars Ingebrigtsen
2021-11-27 15:28                                             ` Stefan Monnier via Bug reports for GNU Emacs, the Swiss army knife of text editors
2021-11-29 13:54                                               ` Lars Ingebrigtsen
2021-11-29 17:58                                                 ` Stefan Monnier via Bug reports for GNU Emacs, the Swiss army knife of text editors
2021-11-30 14:07                                                 ` Michael Heerdegen
2021-11-30 14:20                                                   ` Lars Ingebrigtsen
2021-11-24 16:56               ` Eli Zaretskii

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