Package: emacs;
Reported by: Leo Liu <sdl.web <at> gmail.com>
Date: Tue, 14 May 2013 02:51:03 UTC
Severity: wishlist
Tags: patch
Found in version 24.3
Done: Leo Liu <sdl.web <at> gmail.com>
Bug is archived. No further changes may be made.
View this message in rfc822 format
From: Leo Liu <sdl.web <at> gmail.com> To: Stefan Monnier <monnier <at> IRO.UMontreal.CA> Cc: 14395 <at> debbugs.gnu.org Subject: bug#14395: 24.3; [PATCH] new feature smie-highlight-matching-block Date: Wed, 15 May 2013 15:13:49 +0800
On 2013-05-15 00:02 +0800, Stefan Monnier wrote:
> I don't think enabling it in octave-mode makes sense: this is more like
> "blink-paren vs show-paren-mode", i.e. a personal preference. So the
> enabling/disabling should be done via code in smie.el.
>
>> + (when (and (bound-and-true-p smie-closer-alist)
>
> It's defvarred to nil, so don't test if it's boundp.
>
>> + (let ((open-re (concat "\\_<"
>> + (regexp-opt (mapcar 'car smie-closer-alist))
>> + "\\_>"))
>> + (close-re (concat "\\_<"
>> + (regexp-opt (mapcar 'cdr smie-closer-alist))
>> + "\\_>"))
>
> The string returned by smie-forward-token-function is usually the same
> as the representation of the token in the buffer, but not always.
> So the above is not strictly correct.
>
> Instead you want to call smie-for/backward-token-function and then
> compare the result via (r?assoc tok smie-closer-alist).
>
>> + ((funcall beg-of-tok open-re)
>> + (with-demoted-errors
>> + (forward-sexp 1)
>> + (when (looking-back close-re)
>> + (funcall highlight (match-beginning 0) (match-end 0)))))
>
> I think this should not use with-demoted-errors but instead should
> explicitly catch the scan-error and turn it into a message.
> After all, the user doesn't want to be thrown in the debugger just
> because his sexp is not properly closed yet. And also this way you can
> provide a much nicer error message.
Thank you for your comments, Stefan. I have taken these into account and
new patch attached.
One thing in the patch that I dislike is having to forward-declare
smie-highlight-matching-block-mode. Do you have a cleaner way?
Leo
=== modified file 'lisp/emacs-lisp/smie.el'
--- lisp/emacs-lisp/smie.el 2013-04-25 03:25:34 +0000
+++ lisp/emacs-lisp/smie.el 2013-05-15 07:03:02 +0000
@@ -966,12 +966,15 @@
(let ((starter (funcall smie-forward-token-function)))
(not (member (cons starter ender) smie-closer-alist))))))))
+(defvar smie-highlight-matching-block-mode nil) ; Silence compiler warning
+
(defun smie-blink-matching-open ()
"Blink the matching opener when applicable.
This uses SMIE's tables and is expected to be placed on `post-self-insert-hook'."
(let ((pos (point)) ;Position after the close token.
token)
(when (and blink-matching-paren
+ (not smie-highlight-matching-block-mode)
smie-closer-alist ; Optimization.
(or (eq (char-before) last-command-event) ;; Sanity check.
(save-excursion
@@ -1021,6 +1024,80 @@
(let ((blink-matching-check-function #'smie-blink-matching-check))
(blink-matching-open))))))))
+(defface smie-matching-block-highlight '((t (:inherit highlight)))
+ "Face used to highlight matching block."
+ :group 'smie)
+
+(defvar smie-highlight-matching-block-timer nil)
+(defvar-local smie-highlight-matching-block-overlay nil)
+(defvar-local smie-highlight-matching-block-lastpos -1)
+
+(defun smie-highlight-matching-block ()
+ (when (and smie-closer-alist
+ (/= (point) smie-highlight-matching-block-lastpos))
+ (unless (overlayp smie-highlight-matching-block-overlay)
+ (setq smie-highlight-matching-block-overlay
+ (make-overlay (point) (point))))
+ (setq smie-highlight-matching-block-lastpos (point))
+ (let ((beg-of-tok
+ (lambda (&optional start)
+ "Move to the beginning of current token."
+ (let* ((token)
+ (start (or start (point)))
+ (beg (progn
+ (funcall smie-backward-token-function)
+ (point)))
+ (end (progn
+ (setq token (funcall smie-forward-token-function))
+ (point))))
+ (if (and (<= beg start) (<= start end)
+ (or (assoc token smie-closer-alist)
+ (rassoc token smie-closer-alist)))
+ (progn (goto-char beg) token)
+ (goto-char start)
+ nil))))
+ (highlight (lambda (beg end)
+ (move-overlay smie-highlight-matching-block-overlay
+ beg end)
+ (overlay-put smie-highlight-matching-block-overlay
+ 'face 'smie-matching-block-highlight))))
+ (save-excursion
+ (condition-case nil
+ (if (nth 8 (syntax-ppss))
+ (overlay-put smie-highlight-matching-block-overlay 'face nil)
+ (let ((token
+ (or (funcall beg-of-tok)
+ (funcall beg-of-tok
+ (prog1 (point)
+ (funcall smie-forward-token-function))))))
+ (cond
+ ((assoc token smie-closer-alist) ; opener
+ (forward-sexp 1)
+ (let ((end (point))
+ (closer (funcall smie-backward-token-function)))
+ (when (rassoc closer smie-closer-alist)
+ (funcall highlight (point) end))))
+ ((rassoc token smie-closer-alist) ; closer
+ (funcall smie-forward-token-function)
+ (forward-sexp -1)
+ (let ((beg (point))
+ (opener (funcall smie-forward-token-function)))
+ (when (assoc opener smie-closer-alist)
+ (funcall highlight beg (point)))))
+ (t (overlay-put smie-highlight-matching-block-overlay
+ 'face nil)))))
+ (scan-error
+ (overlay-put smie-highlight-matching-block-overlay 'face nil)))))))
+
+;;;###autoload
+(define-minor-mode smie-highlight-matching-block-mode nil
+ :global t :group 'smie
+ (if smie-highlight-matching-block-mode
+ (setq smie-highlight-matching-block-timer
+ (run-with-idle-timer 0.2 t #'smie-highlight-matching-block))
+ (when (timerp smie-highlight-matching-block-timer)
+ (cancel-timer smie-highlight-matching-block-timer))))
+
;;; The indentation engine.
(defcustom smie-indent-basic 4
GNU bug tracking system
Copyright (C) 1999 Darren O. Benham,
1997,2003 nCipher Corporation Ltd,
1994-97 Ian Jackson.