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From: "Gerd Möllmann" <gerd.moellmann@gmail.com>
To: Matt Armstrong <matt@rfc20.org>, Richard Stallman <rms@gnu.org>
Cc: emacs-devel@gnu.org
Subject: Re: Help sought understanding shorthands wrt modules/packages
Date: Wed, 23 Nov 2022 08:42:56 +0100	[thread overview]
Message-ID: <cefe4ea2-107b-8055-2c1b-6b5cc6cc3f9d@gmail.com> (raw)
In-Reply-To: <871qpubx1p.fsf@rfc20.org>

On 22.11.22 20:37, Matt Armstrong wrote:
> Gerd Möllmann <gerd.moellmann@gmail.com> writes:
> 
>>> The grave problem of :USE in CL packages could be fixed by replacing
>>> it with a new construct that specifies a list of symbols to be
>>> inherited from each other package, perhaos with renaming.
>>
>> I fail to understand the "grave" problem, sorry.  Could you please give
>> a more concrete example?
> 
> A few weeks ago, in this thread or another, I attempted to explain my
> understanding of the point Richard was raising.  As far as I can tell I
> still share the same concern Richard raises.
> 
> The issue is that `(use-package "A")' brings all of A's exported symbols
> into the current namespace, and so allows them to be used unqualified.
> This implies that any addition to a package A's exported symbol list has
> a chance of breaking code in any package that "use-package"'s it.  The
> breakage takes the form of an introduced ambiguity.

Hm, I must admit that I don't see an ambiguity here.  Maybe you are 
thinking of something like the following?

Assume packages A and B, A using B and containing a defun for f.  Next, 
B is modified to export B:f, which A inherits.  A is recompiled, and the 
compiler sees "(defun f () 42)".  In this case, the 'f' refers to B:f, 
but unambiguously.

If that's what you are thinking about, yes that's a known problem, which 
is, in most, if not all, CL implementations, solved with "package 
locks".  In CLisp:

https://clisp.sourceforge.io/impnotes/pack-lock.html

> 
> This is a problem for "programming in the large".  If package's can't
> add new things without risking breaking their users then the approach is
> arguably worse than Emacs' current approach, at least in this respect.
> Adding a new name for a new piece of functionality is one of the most
> common ways packages evolve over time.

But that's not unique to adding symbols.  The same is potentially true 
for all sorts of API changes.

>> BTW, in CL, if you don't want to use-package you can also import just
>> the list of symbols you want.  Without renaming, but I guess that
>> could be added, if somone wants that.  (I mention the idea of renaming
>> in cl-packages.org, BTW, on the branch, but I'm still not sure it's
>> worth it.)
> 
> Yes, Common Lisp provides ways to fix things *after* the breakage
> occurs, but the harm comes with the breakage, and is an inevitable
> consequence of the design.
> 
> Yes, the danger can be avoided by refraining from using `use-package' at
> all.  This is the root my suggestion to consider CL packages for Emacs
> but subtract `use-package'.

Here we have different opinions.  I see no need to forbid use-package. 
Imagine a CL without use-package, being in some package.  I don't want 
to write cl:car everywhere.  What for?

> 
> Yes, this kind of problem exists not only in Common Lisp but many other
> languages, to the extent that some might come to believe this sort of
> problem feels "natural" or is perhaps worth it for the convenience of
> using unqualified names from other packages.  Python's "from foo
> import*" is like CL's use-package and is now widely considered poor
> style in the Python community (for the reasons I've stated). 

Does Python have internal symbols?

> Guile has
> something like Common Lisp, with the same problem and the same kinds of
> mitigating workarounds.  Ada has "use" with semantics similar to CL's.
> Perl has "use" but, presumably through experience, recognized a problem
> and has a "use VERSION" mechanism to limit potential harm from API
> changes.  And on and on.
> 
> The argument is that all of these languages are all flawed in the same
> way, and that a package/module system designed today should aim for
> better.

More power to you :-).




  parent reply	other threads:[~2022-11-23  7:42 UTC|newest]

Thread overview: 125+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-10-30  6:45 Help sought understanding shorthands wrt modules/packages Gerd Möllmann
2022-10-30  8:38 ` tomas
2022-10-30  8:54   ` Eli Zaretskii
2022-10-30  9:14     ` tomas
2022-10-30 10:26       ` Gerd Möllmann
2022-10-30 10:52         ` Eli Zaretskii
2022-10-30 11:24           ` Is there a need for a module system Gerd Möllmann
2022-10-30 11:38             ` Eli Zaretskii
2022-10-30 14:03               ` Gerd Möllmann
2022-10-30 10:40       ` Help sought understanding shorthands wrt modules/packages Eli Zaretskii
2022-10-30 11:06         ` tomas
2022-10-30 11:19           ` Eli Zaretskii
2022-10-30 12:50 ` Stefan Monnier
2022-10-30 13:48   ` Gerd Möllmann
2022-10-30 14:25     ` Stefan Monnier
2022-10-31  6:31       ` Gerd Möllmann
2022-10-30 20:16 ` Helmut Eller
2022-10-31  6:27   ` Gerd Möllmann
2022-10-31 12:13     ` Juanma Barranquero
2022-10-31 12:57       ` Gerd Möllmann
2022-10-31 13:38         ` Juanma Barranquero
2022-10-31 19:53         ` Stefan Monnier
2022-11-11  4:35         ` Richard Stallman
2022-11-11  9:33           ` Gerd Möllmann
2022-11-13  4:17             ` Richard Stallman
2022-11-13  6:41               ` Gerd Möllmann
2022-11-03  3:17     ` Richard Stallman
2022-11-03  5:33       ` Gerd Möllmann
2022-11-03  3:17     ` Richard Stallman
2022-11-03  8:12       ` Michael Albinus
2022-11-03  3:17     ` Richard Stallman
2022-11-03  8:46       ` Eli Zaretskii
2022-11-05 16:49         ` Richard Stallman
2022-11-05 17:04           ` Eli Zaretskii
2022-11-07  7:47             ` Richard Stallman
2022-11-07 12:52               ` Eli Zaretskii
2022-11-08  6:19               ` Gerd Möllmann
2022-11-08  9:54                 ` João Távora
2022-11-08 10:35                   ` Gerd Möllmann
2022-11-08 15:40                     ` João Távora
2022-11-08 15:47                     ` Stefan Kangas
2022-11-08 22:43                       ` João Távora
2022-11-09  6:57                         ` Gerd Möllmann
2022-11-09  7:23                       ` Gerd Möllmann
2022-11-11  4:34                     ` Richard Stallman
2022-11-11  9:25                       ` Gerd Möllmann
2022-11-12  3:35                         ` Richard Stallman
2022-11-19 22:51                           ` [External] : " Drew Adams
2022-11-20  7:18                             ` Eli Zaretskii
2022-11-20 18:55                               ` [External] : " Drew Adams
2022-11-20 19:02                                 ` Eli Zaretskii
2022-11-22 12:14                                 ` [External] : " Richard Stallman
2022-11-22 14:22                                   ` Eli Zaretskii
2022-11-20  8:08                             ` Gerd Möllmann
2022-11-12  3:35                         ` Richard Stallman
2022-11-22 19:37                         ` Matt Armstrong
2022-11-23  7:33                           ` Juanma Barranquero
2022-11-26 23:32                             ` Richard Stallman
2022-11-27  9:05                               ` Juanma Barranquero
2022-11-30 23:55                                 ` Richard Stallman
2022-11-23  7:42                           ` Gerd Möllmann [this message]
2022-12-14 22:21                             ` Richard Stallman
2022-12-15  6:47                               ` Eli Zaretskii
2022-12-17 14:53                                 ` Richard Stallman
2022-11-22 18:01                       ` Matt Armstrong
2022-11-22 18:44                         ` Eli Zaretskii
2022-11-23  0:55                           ` Matt Armstrong
2022-11-23  7:49                             ` Gerd Möllmann
2022-11-23 12:18                             ` Eli Zaretskii
2022-11-11  4:35                 ` Richard Stallman
2022-11-11  9:35                   ` Gerd Möllmann
2022-11-11 12:09                     ` João Távora
2022-11-11 13:01                       ` Gerd Möllmann
2022-11-11 14:23                         ` João Távora
2022-11-11 15:12                           ` Gerd Möllmann
2022-11-12  9:17                             ` João Távora
2022-11-12 13:00                               ` Gerd Möllmann
2022-11-12  3:35                     ` Richard Stallman
2022-11-05 21:47           ` Eduardo Ochs
2022-11-06  9:05           ` Michael Albinus
2022-11-06 11:19             ` João Távora
2022-11-11  4:35               ` Richard Stallman
2022-11-11 10:09                 ` João Távora
2022-11-12  3:35                   ` Richard Stallman
2022-11-12 10:11                     ` João Távora
2022-11-12 14:36                       ` Dmitry Gutov
2022-11-12 15:20                         ` João Távora
2022-11-12 17:32                           ` Dmitry Gutov
2022-11-12 18:45                             ` João Távora
2022-11-14  1:03                               ` Dmitry Gutov
2022-11-14  6:33                                 ` João Távora
2022-11-14 11:41                                   ` Dmitry Gutov
2022-11-14 13:41                                     ` João Távora
2022-11-14  3:13                             ` Richard Stallman
2022-11-11  4:35             ` Richard Stallman
2022-11-11  8:53               ` Michael Albinus
2022-11-11  4:35   ` Richard Stallman
2022-11-11  7:10     ` Helmut Eller
2022-11-01  3:11 ` Ag Ibragimov
2022-11-02 20:11 ` João Távora
2022-11-03  5:12   ` Gerd Möllmann
2022-11-03 20:04     ` A short defense of shorthands.el (but CL packages are still better) (Was: Help sought understanding shorthands wrt modules/packages) João Távora
2022-11-04  3:28       ` Richard Stallman
2022-11-05  1:09         ` A short defense of shorthands.el (but CL packages are still better) João Távora
2022-11-07  7:44           ` Richard Stallman
2022-11-07 10:18             ` João Távora
2022-11-08  5:02               ` Richard Stallman
2022-11-08  5:18                 ` João Távora
2022-11-05  3:13     ` Help sought understanding shorthands wrt modules/packages Richard Stallman
2022-11-06 11:31       ` João Távora
2022-11-08  0:27         ` Matt Armstrong
2022-11-08  4:52           ` João Távora
2022-11-08  5:34             ` Gerd Möllmann
2022-11-09  4:03           ` Richard Stallman
2022-11-09  5:13             ` Matt Armstrong
2022-11-09  4:03           ` Richard Stallman
2022-11-09  5:42             ` Yuri Khan
2022-11-09  5:48               ` tomas
2022-11-09  6:02             ` Matt Armstrong
2022-11-09  7:15               ` Juanma Barranquero
2022-11-09  8:34               ` Gerd Möllmann
2022-11-09 10:07             ` Helmut Eller
2022-11-09 18:22               ` Matt Armstrong
  -- strict thread matches above, loose matches on Subject: below --
2022-11-07 21:20 Payas Relekar
2022-11-08  9:40 ` João Távora

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