From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.org!not-for-mail From: David Kastrup Newsgroups: gmane.emacs.devel Subject: Re: Creating a coding system Date: Thu, 25 Dec 2014 07:39:30 +0100 Message-ID: <877fxgb5ct.fsf@fencepost.gnu.org> References: <87h9wmd8ey.fsf@fencepost.gnu.org> <87a92d2ikx.fsf@gnu.org> NNTP-Posting-Host: plane.gmane.org Mime-Version: 1.0 Content-Type: text/plain X-Trace: ger.gmane.org 1419597573 25573 80.91.229.3 (26 Dec 2014 12:39:33 GMT) X-Complaints-To: usenet@ger.gmane.org NNTP-Posting-Date: Fri, 26 Dec 2014 12:39:33 +0000 (UTC) Cc: emacs-devel@gnu.org To: handa@gnu.org (K. Handa) Original-X-From: emacs-devel-bounces+ged-emacs-devel=m.gmane.org@gnu.org Fri Dec 26 13:39:26 2014 Return-path: Envelope-to: ged-emacs-devel@m.gmane.org Original-Received: from lists.gnu.org ([208.118.235.17]) by plane.gmane.org with esmtp (Exim 4.69) (envelope-from ) id 1Y4UAv-0003F2-R9 for ged-emacs-devel@m.gmane.org; Fri, 26 Dec 2014 13:39:25 +0100 Original-Received: from localhost ([::1]:53192 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Y4UAv-0007b7-9H for ged-emacs-devel@m.gmane.org; Fri, 26 Dec 2014 07:39:25 -0500 Original-Received: from eggs.gnu.org ([2001:4830:134:3::10]:44849) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Y4UAY-0007YB-9u for emacs-devel@gnu.org; Fri, 26 Dec 2014 07:39:03 -0500 Original-Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1Y4UAX-00048W-Io for emacs-devel@gnu.org; Fri, 26 Dec 2014 07:39:02 -0500 Original-Received: from fencepost.gnu.org ([2001:4830:134:3::e]:60036) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Y4UAX-00048P-GC for emacs-devel@gnu.org; Fri, 26 Dec 2014 07:39:01 -0500 Original-Received: from localhost ([127.0.0.1]:38978 helo=lola) by fencepost.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Y4UAX-0001jZ-3N; Fri, 26 Dec 2014 07:39:01 -0500 Original-Received: by lola (Postfix, from userid 1000) id 0880BE0565; Thu, 25 Dec 2014 07:39:30 +0100 (CET) In-Reply-To: <87a92d2ikx.fsf@gnu.org> (K. Handa's message of "Thu, 25 Dec 2014 00:06:22 +0900") User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/25.0.50 (gnu/linux) X-detected-operating-system: by eggs.gnu.org: Error: Malformed IPv6 address (bad octet value). X-Received-From: 2001:4830:134:3::e X-BeenThere: emacs-devel@gnu.org X-Mailman-Version: 2.1.14 Precedence: list List-Id: "Emacs development discussions." List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: emacs-devel-bounces+ged-emacs-devel=m.gmane.org@gnu.org Original-Sender: emacs-devel-bounces+ged-emacs-devel=m.gmane.org@gnu.org Xref: news.gmane.org gmane.emacs.devel:180683 Archived-At: handa@gnu.org (K. Handa) writes: > In article <87h9wmd8ey.fsf@fencepost.gnu.org>, David Kastrup writes: >> > The other method is to use CCL (i.e :coding-type 'ccl), but, >> > if the combination of the charset decoding and translation >> > table works, it's faster than running CCL code. > >> The translation table is not happy about translating things to nothing. >> Apparently that makes the calculation of the reverse translation go >> wrong. > > Ah, perhaps make-translation-table-from-alist should have > optional argument to suppress building of reverse map, say > no-reverse-mmap. Just for decoding, we don't need a reverse > map. Whether we need it or not, empty productions should just be allowed and ignored for reverse translation. Of course, they are not compatible with lossless conversions, but so are many other rules. -- David Kastrup