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From: Alan Mackenzie <acm@muc.de>
To: Eli Zaretskii <eliz@gnu.org>
Cc: acorallo@gnu.org, 66750@debbugs.gnu.org,
	monnier@iro.umontreal.ca, acm@muc.de, stefankangas@gmail.com
Subject: bug#66750: Unhelpful text in C-h v for variables with a lambda form as value
Date: Sat, 28 Oct 2023 18:59:14 +0000	[thread overview]
Message-ID: <ZT1aAg7G0Ob5bAE8@ACM> (raw)
In-Reply-To: <838r7md237.fsf@gnu.org>

Hello, Eli.

On Sat, Oct 28, 2023 at 21:38:36 +0300, Eli Zaretskii wrote:
> > Cc: 66750@debbugs.gnu.org, Andrea Corallo <acorallo@gnu.org>,
> >  Stefan Kangas <stefankangas@gmail.com>, acm@muc.de
> > Date: Sat, 28 Oct 2023 18:17:04 +0000
> > From: Alan Mackenzie <acm@muc.de>

> > > but that's 127kB, so ... could [you] briefly describe the overall design
> > > (IOW, how it's seen by ELisp programmers, byte-compiler hackers, and
> > > ELisp users)?

> > Certainly.  Each lambda expression has (usually) a defun within which it
> > is defined.  Sometimes it's in a defvar, or defcustom.  That
> > @dfn{defining symbol} is recorded in the lambda form in one of three
> > ways:
> > (i) For a cons form, it's (cadr form), a new field inserted between the
> >   symbol `lambda' and the argument list.
> > (ii) For a byte-compiled form, it's (aref form 5), this new field going
> >   after the doc string and before any interactive form in the compiled
> >   form.
> > (iii) For a native-compiled subr it's (subr-native-defining-symbol
> > subr), a function defined in data.c.  It accesses a new field in struct
> > Lisp_Subr called defining_symbol.

> > There are lots of detailed changes in eval.c and bytecomp.el (and
> > friends).  Also the macro `lambda' in subr.el has been amended to insert
> > the current global defining-symbol if there isn't already a non-nil
> > symbol in that position.  cl-print-object/compiled-function has been
> > amended to print the defining-symbol, and there is a new
> > cl-print-object/subr which does the same.

> > The intention is that compiled objects from earlier Emacsen can still be
> > loaded and run by feature/named-lambdas, just without the defining
> > symbols (which will appear to be nil).

> > > Also, what other approaches have you considered/tried and what were the
> > > problems you've encountered, if any?

> > feature/named-lambdas was originally intended for use in backtraces.

> > For the current bug, I've considered individually replacing each lambda
> > with a named defun, so that C-h v will show that name rather than an
> > unhelpful byte/native compiled anonymous function.  That would be a lot
> > of work - my scripting found 63 defcustoms set to lambdas, 29 uses in
> > doc strings, and 215 suspicious occurrences with ordinary variables
> > (quite a few of which will be harmless).  Amending all these (I guess
> > around 200 lambdas) would probably be too much work.

> Thanks.  However, now I'm confused: what exactly does this feature
> give us, if it doesn't handle all the lambdas in the Emacs tree and
> (AFAIU) will not affect lambdas in third-party packages?  Which
> lambdas will now have a defining symbol, and which will not?

It will handle all the lambdas in the Emacs tree.  Each of them will get
a defining-symbol set.  Also third-party packages with lambdas will also
get defining-symbols, provided they are compiled with
feature/named-lambdas.  It's just that .elc's/.eln's built with, say,
Emacs-29 will continue to be loadable and runnable, but obviously without
the defining symbol facility for those lambdas.

-- 
Alan Mackenzie (Nuremberg, Germany).





  reply	other threads:[~2023-10-28 18:59 UTC|newest]

Thread overview: 44+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-10-25 17:09 bug#66750: Unhelpful text in C-h v for variables with a lambda form as value Alan Mackenzie
2023-10-25 20:53 ` Andrea Corallo
2023-10-27 11:35   ` Alan Mackenzie
2023-10-28  9:27     ` Alan Mackenzie
2023-10-28 15:04     ` Stefan Kangas
2023-10-28 15:59       ` Alan Mackenzie
2023-10-28 16:26         ` Eli Zaretskii
2023-10-28 16:57           ` Alan Mackenzie
2023-10-28 17:17         ` Stefan Monnier via Bug reports for GNU Emacs, the Swiss army knife of text editors
2023-10-28 18:17           ` Alan Mackenzie
2023-10-28 18:38             ` Eli Zaretskii
2023-10-28 18:59               ` Alan Mackenzie [this message]
2023-10-28 19:13             ` Stefan Monnier via Bug reports for GNU Emacs, the Swiss army knife of text editors
2023-10-28 19:59               ` Alan Mackenzie
2023-10-29  4:14                 ` Stefan Monnier via Bug reports for GNU Emacs, the Swiss army knife of text editors
2023-10-29 11:25                   ` Alan Mackenzie
2023-10-29 16:32                     ` Stefan Monnier via Bug reports for GNU Emacs, the Swiss army knife of text editors
2023-10-29 18:50                       ` Alan Mackenzie
2023-10-29 21:47                         ` Stefan Monnier via Bug reports for GNU Emacs, the Swiss army knife of text editors
2023-10-30  9:44                           ` Alan Mackenzie
2023-11-01 12:47                             ` Stefan Monnier via Bug reports for GNU Emacs, the Swiss army knife of text editors
2023-11-01 15:03                               ` Alan Mackenzie
2023-11-01 18:11                                 ` Stefan Monnier via Bug reports for GNU Emacs, the Swiss army knife of text editors
2023-11-01 20:30                                   ` Alan Mackenzie
2023-11-01 22:46                                     ` Stefan Monnier via Bug reports for GNU Emacs, the Swiss army knife of text editors
2023-11-02  6:13                                       ` Eli Zaretskii
2023-11-02  9:37                                         ` Alan Mackenzie
2023-11-02 10:09                                           ` Eli Zaretskii
2023-11-02 11:52                                             ` Alan Mackenzie
2023-11-02 13:50                                               ` Eli Zaretskii
2023-11-02 15:55                                                 ` Alan Mackenzie
2023-11-02 16:50                                                   ` Eli Zaretskii
2023-11-02 17:12                                                     ` Andrea Corallo
2023-11-02 21:44                                                   ` Stefan Kangas
2023-11-02 22:24                                                     ` Alan Mackenzie
2023-11-03  3:20                                                       ` Stefan Monnier via Bug reports for GNU Emacs, the Swiss army knife of text editors
2023-11-03 19:46                                                         ` Alan Mackenzie
2023-11-03 22:18                                                           ` Stefan Monnier via Bug reports for GNU Emacs, the Swiss army knife of text editors
2023-11-04 15:31                                                             ` Alan Mackenzie
2023-11-26 12:32                                                             ` Alan Mackenzie
2023-11-27 17:23                                                               ` Stefan Monnier via Bug reports for GNU Emacs, the Swiss army knife of text editors
2024-03-25 12:03                                                         ` Alan Mackenzie
2023-11-02 20:53               ` Stefan Kangas
2023-11-02 21:20                 ` bug#66750: help-split-fundoc (was: bug#66750: Unhelpful text in C-h v for variables with a lambda form as value) Stefan Monnier via Bug reports for GNU Emacs, the Swiss army knife of text editors

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