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#4289
23.1; Incorrect indentation in C, following certain 'case' labels
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Hi, Benjamin!
On Sat, Aug 29, 2009 at 04:59:54PM -0400, Benjamin Moody wrote:
> In Emacs 23.1, I've found an issue with the indentation rules for C
> mode. In some circumstances, following a series of multiple labels,
> the second and subsequent statements are not indented properly. For
> example, in the following code:
> void foo(int x)
> {
> switch (x) {
> case 1:
> case 2:
> printf("aaa");
> break;
> case '3':
> case '4':
> printf("bbb");
> break;
> }
> }
> the second 'break' statement should be indented by 4 spaces, to align
> with the 'printf'.
Indeed it should.
> This problem seems to appear when there are multiple labels (either
> normal named labels, 'case' labels, or 'default' labels) in a row,
> with no intervening statments, and either the first or the last such
> label is a 'case' label with a character constant as its value.
> This problem does NOT occur with Emacs 22.3. It does occur in C++ and
> ObjC modes as well. It affects indentation using either TAB or M-x
> indent-region.
> A workaround is to place the character constant(s) in parentheses.
Yuck!
> This is obviously not a serious problem, ...
I might disagree about that.
> ... but it is a somewhat annoying one which would be nice to see fixed.
OK. Would you please test the patch below, which I think fixes it. Once
you've applied the patch, please rebuild the CC Mode files as follows:
M-x byte-compile-file cc-langs.el
M-x byte-compile-file cc-engine.el
M-x byte-compile-file cc-mode.el
(This is needed because cc-{engine,mode}.el use macros contained in
cc-langs.el.) Then restart Emacs if necessary, then test your file.
Thank you indeed for such a wonderfully clear, concise and helpful bug
report!
Index: cc-engine.el
===================================================================
RCS file: /cvsroot/emacs/emacs/lisp/progmodes/cc-engine.el,v
retrieving revision 1.76
diff -c -r1.76 cc-engine.el
*** cc-engine.el 29 Aug 2009 02:07:45 -0000 1.76
--- cc-engine.el 31 Aug 2009 19:55:19 -0000
***************
*** 1067,1074 ****
(not (eq ret 'beginning))
(looking-at c-case-kwds-regexp))
(if (< after-case:-pos start)
! (setq pos after-case:-pos)
! (setq ret 'label)))
;; Skip over the unary operators that can start the statement.
(while (progn
--- 1067,1075 ----
(not (eq ret 'beginning))
(looking-at c-case-kwds-regexp))
(if (< after-case:-pos start)
! (setq pos after-case:-pos))
! (if (eq ret 'same)
! (setq ret 'label)))
;; Skip over the unary operators that can start the statement.
(while (progn
Index: cc-langs.el
===================================================================
RCS file: /cvsroot/emacs/emacs/lisp/progmodes/cc-langs.el,v
retrieving revision 1.67
diff -c -r1.67 cc-langs.el
*** cc-langs.el 19 May 2009 22:35:07 -0000 1.67
--- cc-langs.el 31 Aug 2009 19:55:21 -0000
***************
*** 2885,2891 ****
i.e. before \":\". Only used if `c-recognize-colon-labels' is set."
t (concat
;; Don't allow string literals.
! "[\"']\\|"
;; All keywords except `c-label-kwds' and `c-protection-kwds'.
(c-make-keywords-re t
(set-difference (c-lang-const c-keywords)
--- 2885,2891 ----
i.e. before \":\". Only used if `c-recognize-colon-labels' is set."
t (concat
;; Don't allow string literals.
! "\"\\|"
;; All keywords except `c-label-kwds' and `c-protection-kwds'.
(c-make-keywords-re t
(set-difference (c-lang-const c-keywords)
> Benjamin Moody
--
Alan Mackenzie (Nuremberg, Germany)
This bug report was last modified 15 years and 218 days ago.
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