emacs manual: codepage-setup vs language environ

emacs manual: codepage-setup vs language environ

[Kevin Ryde]

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In GNU Emacs 21.4.1 (i386-pc-linux-gnu, X toolkit, Xaw3d scroll bars)
 of 2005-03-18 on trouble, modified by Debian
configured using `configure '--build=i386-linux' '--host=i386-linux' '--prefix=/usr' '--sharedstatedir=/var/lib' '--libexecdir=/usr/lib' '--localstatedir=/var/lib' '--infodir=/usr/share/info' '--mandir=/usr/share/man' '--with-pop=yes' '--with-x=yes' '--with-x-toolkit=athena' 'CFLAGS=-DDEBIAN -g -O2' 'build_alias=i386-linux' 'host_alias=i386-linux''
Important settings:
  value of $LC_ALL: en_AU
  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: nil
  locale-coding-system: iso-latin-1
  default-enable-multibyte-characters: t

Please describe exactly what actions triggered the bug
and the precise symptoms of the bug:


The "MS-DOS and MULE" node in the emacs manual says

	Since the codepage number also indicates which script you are
	using, Emacs automatically runs `set-language-environment' to
	select the language environment for that script (*note
	Language Environments::).

When I first read that I thought it applied to both the M-x
dos-codepage-setup and M-x codepage-setup commands shown at the start
of that section, whereas if I'm not mistaken it's only the former.

I think that node could be clearer if the description of how codepages
are handled with emacs coding systems (and how you need M-x
codepage-setup) was separated from the bits about what happens in
emacs actually running on DOS.  The coding systems bits would apply to
all systems, if I'm not mistaken.

Re: emacs manual: codepage-setup vs language environ

[Eli Zaretskii]

> From: Kevin Ryde <user42@zip.com.au>
> Date: Thu, 04 Aug 2005 09:39:35 +1000
> 
> 	Since the codepage number also indicates which script you are
> 	using, Emacs automatically runs `set-language-environment' to
> 	select the language environment for that script (*note
> 	Language Environments::).
> 
> When I first read that I thought it applied to both the M-x
> dos-codepage-setup and M-x codepage-setup commands shown at the start
> of that section, whereas if I'm not mistaken it's only the former.

Actually, it applies to the Emacs startup on MS-DOS.

> I think that node could be clearer if the description of how codepages
> are handled with emacs coding systems (and how you need M-x
> codepage-setup) was separated from the bits about what happens in
> emacs actually running on DOS.

The node you quoted is from an appendix that describes the MS-DOS port
of Emacs, which uses codepage.el.  On other systems, Emacs uses a
different implementation of code pages, the one from code-pages.el.
That package is simply not documented; if we want to document the code
page facilities on systems other than MS-DOS, that information should
be added somewhere else in the manual, not in the DOS appendix, IMHO.

Re: emacs manual: codepage-setup vs language environ

[Kevin Ryde]

Eli Zaretskii <eliz@gnu.org> writes:
>
> The node you quoted is from an appendix that describes the MS-DOS port
> of Emacs, which uses codepage.el.

Ahh, I didn't spot that.  Yes, the heading is "on MS-DOS", but I was
there to find out about codepages.  The "Coding Systems" node points
to "MS-DOS and MULE" for codepages, maybe it shouldn't if that's
supposed to be dos specific.

For the cvs head, maybe the pointer in "Coding Systems" can be
dropped, and if M-x codepage-setup is only needed on DOS then maybe
that could be said in "MS-DOS and MULE", to avoid confusion.

Re: emacs manual: codepage-setup vs language environ

[Eli Zaretskii]

> From: Kevin Ryde <user42@zip.com.au>
> Cc: Eli Zaretskii <eliz@gnu.org>
> Date: Sat, 06 Aug 2005 11:30:36 +1000
> 
> Eli Zaretskii <eliz@gnu.org> writes:
> >
> > The node you quoted is from an appendix that describes the MS-DOS port
> > of Emacs, which uses codepage.el.
> 
> Ahh, I didn't spot that.  Yes, the heading is "on MS-DOS", but I was
> there to find out about codepages.  The "Coding Systems" node points
> to "MS-DOS and MULE" for codepages, maybe it shouldn't if that's
> supposed to be dos specific.
> 
> For the cvs head, maybe the pointer in "Coding Systems" can be
> dropped, and if M-x codepage-setup is only needed on DOS then maybe
> that could be said in "MS-DOS and MULE", to avoid confusion.

I did the latter.  I don't think it's a good idea to drop the index
entry for "Coding Systems", as long as the MS-DOS port is supported.