From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.org!not-for-mail From: =?ISO-8859-1?Q?Nordl=F6w?= Newsgroups: gmane.emacs.help Subject: Error-Free Navigation in Trees of Sub-Expressions (sexp) in Font-Locking Function Matchers Date: Wed, 8 Oct 2008 05:24:16 -0700 (PDT) Organization: http://groups.google.com Message-ID: NNTP-Posting-Host: lo.gmane.org Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable X-Trace: ger.gmane.org 1223469735 11263 80.91.229.12 (8 Oct 2008 12:42:15 GMT) X-Complaints-To: usenet@ger.gmane.org NNTP-Posting-Date: Wed, 8 Oct 2008 12:42:15 +0000 (UTC) To: help-gnu-emacs@gnu.org Original-X-From: help-gnu-emacs-bounces+geh-help-gnu-emacs=m.gmane.org@gnu.org Wed Oct 08 14:43:09 2008 Return-path: Envelope-to: geh-help-gnu-emacs@m.gmane.org Original-Received: from lists.gnu.org ([199.232.76.165]) by lo.gmane.org with esmtp (Exim 4.50) id 1KnYMa-0007oN-Vw for geh-help-gnu-emacs@m.gmane.org; Wed, 08 Oct 2008 14:42:01 +0200 Original-Received: from localhost ([127.0.0.1]:34020 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1KnYLX-00052t-3N for geh-help-gnu-emacs@m.gmane.org; Wed, 08 Oct 2008 08:40:55 -0400 Original-Path: news.stanford.edu!newsfeed.stanford.edu!postnews.google.com!p10g2000prf.googlegroups.com!not-for-mail Original-Newsgroups: gnu.emacs.help Original-Lines: 65 Original-NNTP-Posting-Host: 150.227.15.253 Original-X-Trace: posting.google.com 1223468656 25594 127.0.0.1 (8 Oct 2008 12:24:16 GMT) Original-X-Complaints-To: groups-abuse@google.com Original-NNTP-Posting-Date: Wed, 8 Oct 2008 12:24:16 +0000 (UTC) Complaints-To: groups-abuse@google.com Injection-Info: p10g2000prf.googlegroups.com; posting-host=150.227.15.253; posting-account=ytJKAgoAAAA1tg4ScoRszebXiIldA5vg User-Agent: G2/1.0 X-HTTP-UserAgent: Mozilla/5.0 (X11; U; Linux i686; sv-SE; rv:1.9.0.3) Gecko/2008092510 Ubuntu/8.04 (hardy) Firefox/3.0.3, gzip(gfe), gzip(gfe) X-HTTP-Via: 1.1 ip-w.foi.se:8080 (IronPort-WSA/5.6.0-618) Original-Xref: news.stanford.edu gnu.emacs.help:163192 X-BeenThere: help-gnu-emacs@gnu.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Users list for the GNU Emacs text editor List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Original-Sender: help-gnu-emacs-bounces+geh-help-gnu-emacs=m.gmane.org@gnu.org Errors-To: help-gnu-emacs-bounces+geh-help-gnu-emacs=m.gmane.org@gnu.org Xref: news.gmane.org gmane.emacs.help:58534 Archived-At: How can I programmatically iterate over all sexps in an emacs-lisp expression without risking getting an error? I have tried forward- sexp() and backward-sexp() and up/down-list() but these generate an error when I get to the beginning or end in each "direction". Why, on earth, doesn't these functions have an optional argument, say no- error, that inhibits errors in these cases and instead indicates this event by returning nil? I believe I need these functions because I am currently extending font- locking in emacs-lisp-mode to highlight variables in let and defun- like statements. Here is my moccup so far: (defun pnw-fancy/setq-args-matcher (limit) (let ((start (point))) ; remember beginning (if (looking-at (concat "[[:blank:]\n]*" "'?\\(\\w+\\)")) ; One more SYM? (progn (goto-char (match-end 1)) (forward-sexp); skip VAL t)); signal hit )) (defun pnw-fancy/emacs-lisp-variables-font-locking () (font-lock-add-keywords nil (list ;; setq-statements: (setq SYM VAL ...) `(;; MATCHER: (SETQ ,(concat "(" (regexp-opt '("set" "setq" "setq-default" "setq-mode-local") t) "[[:blank:]\n]*") ;; SUBEXP-HIGHLIGHTER (1 'font-lock-function-call-face keep) ;; ANCHORED-HIGHLIGHTER: (setq SYM VAL ...) (;; ANCHORED-MATCHER pnw-fancy/setq-args-matcher nil ; PRE-FORM nil ; POST-FORM (1 'font-lock-variable-name-face prepend) ; SUBEXP-HIGHLIGHTERS )) ) t)) (add-hook 'emacs-lisp-mode-hook 'pnw-fancy/emacs-lisp-variables-font- locking) Test on these examples: (setq a 1 b 2 c 3) (setq a 1 b 2 c 3) (setq x-1 '(1 1) x-2 '(2 2) x-3 '(3 3)) It currently doesn't work for multi-line variants of setq-form. Is this beyond the capabilities of font-lock? As I have said above it siliently errors when the last VAL is missing like in the following statement: (setq a 1 b 2 c) What is the most clever way of checking when we are at the last sexp (forward-sexp will fail as mentioned above)? Thanks in advance, Nordl=F6w