From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.org!not-for-mail From: Stephen Leake Newsgroups: gmane.emacs.devel Subject: Re: Allow xref to use other than current major-mode Date: Tue, 25 Aug 2015 10:31:27 -0500 Message-ID: <867fojidv4.fsf@stephe-leake.org> References: <86fv37it65.fsf@stephe-leake.org> <55DC5612.9050704@yandex.ru> NNTP-Posting-Host: plane.gmane.org Mime-Version: 1.0 Content-Type: text/plain X-Trace: ger.gmane.org 1440516736 19908 80.91.229.3 (25 Aug 2015 15:32:16 GMT) X-Complaints-To: usenet@ger.gmane.org NNTP-Posting-Date: Tue, 25 Aug 2015 15:32:16 +0000 (UTC) To: emacs-devel@gnu.org Original-X-From: emacs-devel-bounces+ged-emacs-devel=m.gmane.org@gnu.org Tue Aug 25 17:32:06 2015 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 1ZUGCi-0001Bv-04 for ged-emacs-devel@m.gmane.org; Tue, 25 Aug 2015 17:32:04 +0200 Original-Received: from localhost ([::1]:32776 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ZUGCh-0004db-99 for ged-emacs-devel@m.gmane.org; Tue, 25 Aug 2015 11:32:03 -0400 Original-Received: from eggs.gnu.org ([2001:4830:134:3::10]:46587) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ZUGCS-0004aK-9w for emacs-devel@gnu.org; Tue, 25 Aug 2015 11:31:49 -0400 Original-Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1ZUGCP-0002hb-1Q for emacs-devel@gnu.org; Tue, 25 Aug 2015 11:31:48 -0400 Original-Received: from gproxy1-pub.mail.unifiedlayer.com ([69.89.25.95]:38346) by eggs.gnu.org with smtp (Exim 4.71) (envelope-from ) id 1ZUGCO-0002hD-Ri for emacs-devel@gnu.org; Tue, 25 Aug 2015 11:31:44 -0400 Original-Received: (qmail 30069 invoked by uid 0); 25 Aug 2015 15:31:40 -0000 Original-Received: from unknown (HELO cmgw3) (10.0.90.84) by gproxy1.mail.unifiedlayer.com with SMTP; 25 Aug 2015 15:31:40 -0000 Original-Received: from host114.hostmonster.com ([74.220.207.114]) by cmgw3 with id 99XX1r0092UdiVW019Xave; Tue, 25 Aug 2015 15:31:39 -0600 X-Authority-Analysis: v=2.1 cv=GpXRpCFC c=1 sm=1 tr=0 a=CQdxDb2CKd3SRg4I0/XZPQ==:117 a=CQdxDb2CKd3SRg4I0/XZPQ==:17 a=DsvgjBjRAAAA:8 a=f5113yIGAAAA:8 a=9i_RQKNPAAAA:8 a=y7kgw_RnJtkA:10 a=hEr_IkYJT6EA:10 a=x_XPkuGwIRMA:10 a=uRRa74qj2VoA:10 a=vaJtXVxTAAAA:8 a=hR1_yj2NAw0y_7k_RFQA:9 Original-Received: from [76.218.37.33] (port=62788 helo=TAKVER2) by host114.hostmonster.com with esmtpa (Exim 4.84) (envelope-from ) id 1ZUGCB-0001U5-Rh for emacs-devel@gnu.org; Tue, 25 Aug 2015 09:31:32 -0600 In-Reply-To: <55DC5612.9050704@yandex.ru> (Dmitry Gutov's message of "Tue, 25 Aug 2015 14:48:34 +0300") User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/24.5 (windows-nt) X-Identified-User: {2442:host114.hostmonster.com:stephele:stephe-leake.org} {sentby:smtp auth 76.218.37.33 authed with stephen_leake@stephe-leake.org} X-detected-operating-system: by eggs.gnu.org: GNU/Linux 3.x X-Received-From: 69.89.25.95 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:189167 Archived-At: Dmitry Gutov writes: > On 08/25/2015 01:00 PM, Stephen Leake wrote: > >> To handle this, I propose changing both >> xref-identifier-completion-table-function and xref-find-function to be >> mode-local, instead of buffer-local. > > That seems unnecessarily limiting. First, mode-local facility is a > part of CEDET, so it would need to be always loaded. I realized after I posted that mode-local.el is not pre-loaded, so elisp-mode.el can't require it. That said, mode-local.el is only one file; nothing else in CEDET is required. cl-generic.el is preloaded, so we could use a cl-defgeneric, and dispatch on (mode (eql )). > Second, how would a minor mode set an xref backend? It might not be > tied to a particular major mode. I don't see how a global minor mode can set an xref backend now. To make such a minor mode work, xref--read-identifier could be a cl-defgeneric that dispatches on (project )), each backend would have to define all combinations; that's a pain. >> There are similar use cases; from a LaTeX document buffer, looking at the >> description of an Ada function, find the Ada code that defines that >> function. Or from a text mode notes file, look for a definition in any >> one of several languages. > > All similar cases can be solved by a project-aware xref backend that > knows about all languages used, and allows navigating to identifiers > in all of them. I've started writing such a thing, but it gets defeated by the fact that xref--read-identifier uses the buffer-local value of xref-identifier-completion-table-function, which is set by elisp-mode (or c-mode, etc, or by default to etags). There's no way to change that. We could require the user to manually enable an xref minor mode in each buffer, but that's not friendly. I guess a global xref backend could somehow reset that variable, in all elisp buffers? Maybe a function on elisp-mode-hook. The problem is that emacs-lisp-mode sets the buffer-local xref variables, but I don't want it to. So a better approach would be to define a way to disable emacs-lisp-mode (and all other major-modes) setting the xref buffer-local variables, so that the user choice of xref backend is respected. That would be much simpler than having to add a function to all the major mode hooks (most of which are unknown at load time). We could define a new global variable xref-global-backend; if nil (the default), major modes can set xref vars; if non-nil, it indicates which particular global backend is in use. It could be a function that returns a boolean indicating whether the global backend wants to control xref in the current buffer. So a semi-global backend could provide C and Ada xref, but not elisp xref, for example. It could be a list of such functions; only if all return nil should the major mode set the xref vars. -- -- Stephe