GNU bug report logs - #4869
23.1.50; weak documentation of prefer-coding-system

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Message #5 received at submit <at> emacsbugs.donarmstrong.com (full text, mbox):

From: Joseph Brenner <doom <at> kzsu.stanford.edu>
To: emacs-pretest-bug <at> gnu.org
Subject: 23.1.50; weak documentation of prefer-coding-system
Date: Wed, 04 Nov 2009 13:25:09 -0800

The function prefer-coding-system does not explain if the CODING-SYSTEM
argument must be a symbol or a string (or either).

Without seeing a code example, a user might try using a quoted string:

   (prefer-coding-system "utf-8")

In which case, the error message is very confusing (this makes it sound
as though utf-8 is not supported):

   error: Invalid coding system `utf-8'

At a minimum, the documentation should be made more explicit, and I
would strongly suggest adding a code example:

   (prefer-coding-system 'utf-8)


In GNU Emacs 23.1.50.1 (x86_64-unknown-linux-gnu, GTK+ Version 2.16.1)
 of 2009-10-22 on fineline
Windowing system distributor `The X.Org Foundation', version 11.0.10600000
configured using `configure  '--prefix' '/usr/local/emacs/cvs-102209''

Important settings:
  value of $LC_ALL: nil
  value of $LC_COLLATE: nil
  value of $LC_CTYPE: nil
  value of $LC_MESSAGES: nil
  value of $LC_MONETARY: nil
  value of $LC_NUMERIC: nil
  value of $LC_TIME: nil
  value of $LANG: en_US.UTF-8
  value of $XMODIFIERS: nil
  locale-coding-system: utf-8-unix
  default enable-multibyte-characters: t

Major mode: Text

Minor modes in effect:
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  display-time-mode: t
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Recent input:
<return> g f C-x 1 s C-p C-p C-p C-p <return> SPC SPC
<return> C-p C-p o C-n C-n + P i c k <return> C-n R
P i r SPC <backspace> c SPC <return> <return> SPC <return>
C-p C-p f o <backspace> C-n C-x 2 C-x o M-x s h e l
l <return> k 3 b SPC & <return> C-x 0 C-x 2 ^ ^ ^ g
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<switch-frame> <switch-frame> <switch-frame> C-x o
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C-o D r e w SPC A d m a <backspace> <backspace> a m
s SPC n u d g e s SPC m e SPC t o SPC d o SPC a SPC
b u f <backspace> g SPC r e p o r t : C-x C-s C-x C-p
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M-w C-x C-p M-h i u u u <return> s C-y <return> <prior>
u u u C-n C-n C-n C-n C-n C-n C-a <return> s <return>
s <return> s <return> C-x 0 C-a M-x r e p o r t SPC
e m SPC b SPC <return>

Recent messages:
Searching subfile elisp-2...
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Searching subfile elisp-8...
Searching subfile elisp-9...
Searching subfile elisp-10...
Searching subfile elisp-11...
Info-search: Search failed: "prefer-coding-system"

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Message #10 received at 4869 <at> emacsbugs.donarmstrong.com (full text, mbox):

From: Juri Linkov <juri <at> jurta.org>
To: Joseph Brenner <doom <at> kzsu.stanford.edu>
Cc: 4869 <at> debbugs.gnu.org
Subject: Re: bug#4869: 23.1.50; weak documentation of prefer-coding-system
Date: Fri, 06 Nov 2009 03:47:28 +0200

> The function prefer-coding-system does not explain if the CODING-SYSTEM
> argument must be a symbol or a string (or either).
>
> Without seeing a code example, a user might try using a quoted string:
>
>    (prefer-coding-system "utf-8")
>
> In which case, the error message is very confusing (this makes it sound
> as though utf-8 is not supported):
>
>    error: Invalid coding system `utf-8'
>
> At a minimum, the documentation should be made more explicit, and I
> would strongly suggest adding a code example:
>
>    (prefer-coding-system 'utf-8)

Why not allow both?  Some MULE functions allow a symbol and a string.

-- 
Juri Linkov
http://www.jurta.org/emacs/

Message #15 received at 4869 <at> emacsbugs.donarmstrong.com (full text, mbox):

From: Lennart Borgman <lennart.borgman <at> gmail.com>
To: Juri Linkov <juri <at> jurta.org>, 4869 <at> debbugs.gnu.org
Cc: Joseph Brenner <doom <at> kzsu.stanford.edu>
Subject: Re: bug#4869: 23.1.50; weak documentation of prefer-coding-system
Date: Fri, 6 Nov 2009 03:50:03 +0100

On Fri, Nov 6, 2009 at 2:47 AM, Juri Linkov <juri <at> jurta.org> wrote:
>> The function prefer-coding-system does not explain if the CODING-SYSTEM
>> argument must be a symbol or a string (or either).
>>
>> Without seeing a code example, a user might try using a quoted string:
>>
>>    (prefer-coding-system "utf-8")
>>
>> In which case, the error message is very confusing (this makes it sound
>> as though utf-8 is not supported):
>>
>>    error: Invalid coding system `utf-8'
>>
>> At a minimum, the documentation should be made more explicit, and I
>> would strongly suggest adding a code example:
>>
>>    (prefer-coding-system 'utf-8)
>
> Why not allow both?  Some MULE functions allow a symbol and a string.

Because it is at least a rudimentary type check? ;-)

Message #20 received at 4869 <at> emacsbugs.donarmstrong.com (full text, mbox):

From: Eli Zaretskii <eliz <at> gnu.org>
To: Lennart Borgman <lennart.borgman <at> gmail.com>,
        4869 <at> debbugs.gnu.org
Cc: juri <at> jurta.org, doom <at> kzsu.stanford.edu
Subject: Re: bug#4869: 23.1.50; weak documentation of prefer-coding-system
Date: Fri, 06 Nov 2009 10:41:42 +0200

> From: Lennart Borgman <lennart.borgman <at> gmail.com>
> Date: Fri, 6 Nov 2009 03:50:03 +0100
> Cc: Joseph Brenner <doom <at> kzsu.stanford.edu>
> 
> > Why not allow both?  Some MULE functions allow a symbol and a string.
> 
> Because it is at least a rudimentary type check? ;-)

There's no need for this type check because prefer-coding-system
already checks its argument with coding-system-p, which is the full
type check for coding systems.

Message #29 received at 4869 <at> debbugs.gnu.org (full text, mbox):

From: Lars Magne Ingebrigtsen <larsi <at> gnus.org>
To: Joseph Brenner <doom <at> kzsu.stanford.edu>
Cc: 4869 <at> debbugs.gnu.org
Subject: Re: 23.1.50; weak documentation of prefer-coding-system
Date: Wed, 13 Jul 2011 16:34:42 +0200

Joseph Brenner <doom <at> kzsu.stanford.edu> writes:

> At a minimum, the documentation should be made more explicit, and I
> would strongly suggest adding a code example:
>
>    (prefer-coding-system 'utf-8)

I've now added this example to Emacs 24.

-- 
(domestic pets only, the antidote for overdose, milk.)
  bloggy blog http://lars.ingebrigtsen.no/

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