From: Daniel Colascione <dancol@dancol.org>
To: 13182@debbugs.gnu.org
Subject: bug#13182: [PATCH] long delays in python-mode buffer parsing
Date: Fri, 14 Dec 2012 03:40:28 -0800 [thread overview]
Message-ID: <50CB102C.6020306@dancol.org> (raw)
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Some python-mode operations slow down noticeably when the region being edited
contains an unclosed bracket or string: these constructs lead to python-mode
scanning the entire remainder of the buffer, and this scan appears to take time
O(nr_lines^2). When which-func mode is enabled, this slowness renders Emacs
unusable, since we'll call python-info-current-defun frequently in order to
update the modeline, and this function will take several seconds to complete.
The following patch appears to remedy the problem without breaking anythig.
=== modified file 'lisp/progmodes/python.el'
--- lisp/progmodes/python.el 2012-11-27 03:10:32 +0000
+++ lisp/progmodes/python.el 2012-12-14 11:28:58 +0000
@@ -1184,13 +1184,21 @@
(defun python-nav-end-of-statement ()
"Move to end of current statement."
(interactive "^")
- (while (and (goto-char (line-end-position))
- (not (eobp))
- (when (or
- (python-info-line-ends-backslash-p)
- (python-syntax-context 'string)
- (python-syntax-context 'paren))
- (forward-line 1))))
+
+ (let (string-start bs-pos)
+ (while (and (goto-char (line-end-position))
+ (not (eobp))
+ (cond ((setq string-start (python-syntax-context 'string))
+ (goto-char string-start)
+ (forward-sexp))
+ ((python-syntax-context 'paren)
+ ;; The statement won't end before we've escaped
+ ;; at least one level of parenthesis.
+ (condition-case err
+ (goto-char (scan-lists (point) 1 -1))
+ (scan-error (goto-char (nth 3 err)))))
+ ((setq bs-pos (python-info-line-ends-backslash-p))
+ (goto-char bs-pos))))))
(point-marker))
(defun python-nav-backward-statement (&optional arg)
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next reply other threads:[~2012-12-14 11:40 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-12-14 11:40 Daniel Colascione [this message]
2012-12-15 6:44 ` bug#13182: [PATCH] long delays in python-mode buffer parsing Daniel Colascione
2012-12-15 14:50 ` Stefan Monnier
2012-12-28 15:29 ` Fabián Ezequiel Gallina
2012-12-31 21:02 ` Fabián Ezequiel Gallina
2012-12-31 21:05 ` Fabián Ezequiel Gallina
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