From: martin rudalics <rudalics@gmx.at>
To: Stefan Monnier <monnier@iro.umontreal.ca>
Cc: era+emacsbugs@iki.fi, 4030@emacsbugs.donarmstrong.com
Subject: bug#4030: forward-sexp parses character literal ?; as comment
Date: Fri, 07 Aug 2009 15:01:27 +0200 [thread overview]
Message-ID: <4A7C25A7.6000900@gmx.at> (raw)
In-Reply-To: <jwv63d022za.fsf-monnier+emacsbugreports@gnu.org>
>> We could try to mark any `?;' or `?"' sequences appropriately when
>> fontifying though.
>
> We could/should/will improve the syntax parsing to handle those
> things properly. But it's a non-trivial amount of work, especially
> since every major mode has similar issues but needs different
> extra functionality.
But fontification is mode-specific. So it would be sufficient to look
for ?s that are not within strings or comments and followed by a
semicolon, paren or double-quote and mark that appropriately (obviously
the parser is derailed at that time but it still might help people spot
the bug).
>>> I'll also point out that an "Unbalanced parentheses" error from deep
>>> inside Customize is not a very helpful error message (especially as it
>>> does not indicate in which buffer the unbalanced parentheses were
>>> found); but perhaps Customize should be adapted to cope if forward-sexp
>>> cannot easily be fixed.
>> Getting good diagnostics after a parsing error is hard.
>
> Agreed, but that doesn't mean we shouldn't intend to do better: the
> current behavior (signalling an internal error to the user) is a bug
> that needs to be fixed.
If the problem comes from the unprotected
(save-excursion (forward-sexp (buffer-size)))) ; Test for scan errors.
call in `custom-save-delete' we could simply wrap it as in the patch
below. But do we really have to scan the buffer in the first place?
martin
*** cus-edit.el.~1.364.~ 2009-07-27 08:09:05.997162900 +0200
--- cus-edit.el 2009-08-07 14:49:22.890625000 +0200
***************
*** 4341,4347 ****
;; Skip all whitespace and comments.
(while (forward-comment 1))
(or (eobp)
! (save-excursion (forward-sexp (buffer-size)))) ; Test for scan errors.
(let (first)
(catch 'found
(while t ;; We exit this loop only via throw.
--- 4341,4349 ----
;; Skip all whitespace and comments.
(while (forward-comment 1))
(or (eobp)
! (condition-case nil
! (save-excursion (forward-sexp (buffer-size))) ; Test for scan errors.
! (scan-error (error "Scan error, watch out for ... "))))
(let (first)
(catch 'found
(while t ;; We exit this loop only via throw.
next prev parent reply other threads:[~2009-08-07 13:01 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-08-04 12:07 bug#4030: forward-sexp parses character literal ?; as comment era+emacsbugs
2009-08-04 12:43 ` martin rudalics
2009-08-05 8:17 ` era+emacsbugs
2009-08-05 14:29 ` martin rudalics
2009-08-06 8:55 ` era+emacsbugs
2009-08-06 18:51 ` Stefan Monnier
2009-08-07 13:01 ` martin rudalics [this message]
2009-08-10 19:59 ` Stefan Monnier
2009-08-11 9:17 ` martin rudalics
2016-06-18 3:47 ` Andrew Hyatt
2016-06-18 4:31 ` Stefan Monnier
2017-05-13 2:55 ` npostavs
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