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: Emacs Lisp's future Date: Sat, 27 Sep 2014 10:49:37 +0200 Message-ID: <8738bdo3by.fsf@fencepost.gnu.org> References: <54193A70.9020901@member.fsf.org> <87lhp6h4zb.fsf@panthera.terpri.org> <87k34qo4c1.fsf@fencepost.gnu.org> <54257C22.2000806@yandex.ru> <83iokato6x.fsf@gnu.org> <87wq8pwjen.fsf@uwakimon.sk.tsukuba.ac.jp> NNTP-Posting-Host: plane.gmane.org Mime-Version: 1.0 Content-Type: text/plain X-Trace: ger.gmane.org 1411817434 31598 80.91.229.3 (27 Sep 2014 11:30:34 GMT) X-Complaints-To: usenet@ger.gmane.org NNTP-Posting-Date: Sat, 27 Sep 2014 11:30:34 +0000 (UTC) Cc: Eli Zaretskii , Dmitry Antipov , emacs-devel@gnu.org To: "Stephen J. Turnbull" Original-X-From: emacs-devel-bounces+ged-emacs-devel=m.gmane.org@gnu.org Sat Sep 27 13:30:27 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 1XXqCm-0005gr-B3 for ged-emacs-devel@m.gmane.org; Sat, 27 Sep 2014 13:30:24 +0200 Original-Received: from localhost ([::1]:55355 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1XXqCl-0004et-Qt for ged-emacs-devel@m.gmane.org; Sat, 27 Sep 2014 07:30:23 -0400 Original-Received: from eggs.gnu.org ([2001:4830:134:3::10]:47828) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1XXqCV-0004cc-Vo for emacs-devel@gnu.org; Sat, 27 Sep 2014 07:30:09 -0400 Original-Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1XXqCT-0000H8-5R for emacs-devel@gnu.org; Sat, 27 Sep 2014 07:30:07 -0400 Original-Received: from fencepost.gnu.org ([2001:4830:134:3::e]:37347) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1XXqCT-00005c-39 for emacs-devel@gnu.org; Sat, 27 Sep 2014 07:30:05 -0400 Original-Received: from localhost ([127.0.0.1]:44517 helo=lola) by fencepost.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1XXqCM-0007zK-NI; Sat, 27 Sep 2014 07:29:58 -0400 Original-Received: by lola (Postfix, from userid 1000) id F03B3E0534; Sat, 27 Sep 2014 10:49:37 +0200 (CEST) In-Reply-To: <87wq8pwjen.fsf@uwakimon.sk.tsukuba.ac.jp> (Stephen J. Turnbull's message of "Sat, 27 Sep 2014 17:35:12 +0900") User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/24.4.50 (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:174736 Archived-At: "Stephen J. Turnbull" writes: > Eli Zaretskii writes: > > > Date: Fri, 26 Sep 2014 18:45:54 +0400 > > > From: Dmitry Antipov > > > Cc: emacs-devel@gnu.org > > > > > > Why not just use ICU? > > > > Emacs needs to be able to extend the Unicode code-point space for raw > > 8-bit bytes and for a couple of character sets that are not unified. > > No, you don't. There's plenty of private space for those purposes > (unless you know of private character sets that use more than two > whole planes?) Emacs would simply use an indirect representation for > private space. (That is, code points in private space are not > necessarily identical to the input code points, but rather are indexes > into an auxiliary table which implements the disjoint sum of the > private code spaces in use.) > > Since this is private space, you need to build a table of attributes > for these characters (I/O representation, UCD properties, glyphs, etc) > anyway. For Unicode input using private space, you just record that > as the I/O representation. > > > Can ICU support that? > > Maybe it would be unhappy if you used a lone surrogate representation > (or other representation using integers outside of the Unicode > character space) for those "extended code points", but as proposed > above you can efficiently use private space in practice. Except that Emacs, as an editor, needs to support the private spaces users might want to use. Hijacking the surrogates is a reasonable compromise. Another would have been hijacking the 4-byte encodable code space beyond Unicode character 1114111 that is outside of UTF-8 but inside of the coding scheme's logic and thus working equally well for string manipulations: however, that would cause unencodable bytes to take up more space. I think LuaTeX may use that strategy. Being an editor, Emacs has to be more circumspect than most other encoding-sensitive applications about what it may work with since everything that is "private" may well be within the range that a user wants to be able to put into string literals. -- David Kastrup