unofficial mirror of emacs-devel@gnu.org 
 help / color / mirror / code / Atom feed
From: Richard Stallman <rms@gnu.org>
Cc: emacs-devel@gnu.org
Subject: Re: Coding system robustness?
Date: Fri, 18 Mar 2005 22:09:35 -0500	[thread overview]
Message-ID: <E1DCULH-0005AM-Pv@fencepost.gnu.org> (raw)
In-Reply-To: <x54qf8df09.fsf@lola.goethe.zz> (message from David Kastrup on Fri, 18 Mar 2005 18:45:42 +0100)

    I'd like to know whether coding systems in general are supposed to be
    robust, meaning that decoding some random byte string into the coding
    system and reencoding it is guaranteed to deliver the same byte string
    again?

Handa is the expert, but I am sure this is not generally the case.  In
some coding systems there is more than one representation for the same
series of Emacs characters.  I think one of the coding system involves
shift-sequences that switch between sub-coding-systems.  Re-encoding
cannot preserve the shift-sequences.

There may be some coding systems that are 1-1 encodings for the
Emacs characters they can handle.

      parent reply	other threads:[~2005-03-19  3:09 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2005-03-18 17:45 Coding system robustness? David Kastrup
2005-03-18 18:11 ` Stefan Monnier
2005-03-18 18:33   ` David Kastrup
2005-03-20  0:22     ` Richard Stallman
2005-03-19  1:08   ` Kenichi Handa
2005-03-19  9:10     ` David Kastrup
2005-03-19  0:52 ` Kenichi Handa
2005-03-19  3:09 ` Richard Stallman [this message]

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

  List information: https://www.gnu.org/software/emacs/

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=E1DCULH-0005AM-Pv@fencepost.gnu.org \
    --to=rms@gnu.org \
    --cc=emacs-devel@gnu.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body. 
Code repositories for project(s) associated with this public inbox

	https://git.savannah.gnu.org/cgit/emacs.git

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).