bug#13541: 24.2.92; awk-mode: wrong font locking regexp literals

[Alan Mackenzie <acm@muc.de>]

Hi, Leo.

On Thu, Jan 24, 2013 at 07:43:06PM +0800, Leo Liu wrote:
> In an awk buffer having the following text:

> #--BEGIN--
> NF { /xyz/ }

> NF {
>     /xyz/
> }
> #--END--

> I have the second regexp properly font-locked but not the first one.

Yes.

Could you please try out, fairly thoroughly, the following patch, and let
me know how it goes.  It aims to fontify a /regexp/ wherever one might
occur.




=== modified file 'lisp/progmodes/cc-awk.el'
*** lisp/progmodes/cc-awk.el	2013-01-01 09:11:05 +0000
--- lisp/progmodes/cc-awk.el	2013-01-25 17:47:38 +0000
***************
*** 211,217 ****
  ;; division sign.
  (defconst c-awk-neutral-re
  ;  "\\([{}@` \t]\\|\\+\\+\\|--\\|\\\\.\\)+") ; changed, 2003/6/7
!   "\\([{}@` \t]\\|\\+\\+\\|--\\|\\\\.\\)")
  ;;   A "neutral" char(pair).  Doesn't change the "state" of a subsequent /.
  ;; This is space/tab, braces, an auto-increment/decrement operator or an
  ;; escaped character.  Or one of the (invalid) characters @ or `.  But NOT an
--- 211,217 ----
  ;; division sign.
  (defconst c-awk-neutral-re
  ;  "\\([{}@` \t]\\|\\+\\+\\|--\\|\\\\.\\)+") ; changed, 2003/6/7
!   "\\([}@` \t]\\|\\+\\+\\|--\\|\\\\\\(.\\|[\n\r]\\)\\)")
  ;;   A "neutral" char(pair).  Doesn't change the "state" of a subsequent /.
  ;; This is space/tab, braces, an auto-increment/decrement operator or an
  ;; escaped character.  Or one of the (invalid) characters @ or `.  But NOT an
***************
*** 231,237 ****
  ;; will only work when there won't be a preceding " or / before the sought /
  ;; to foul things up.
  (defconst c-awk-non-arith-op-bra-re
!   "[[\(&=:!><,?;'~|]")
  ;;   Matches an opening BRAcket, round or square, or any operator character
  ;; apart from +,-,/,*,%.  For the purpose at hand (detecting a / which is a
  ;; regexp bracket) these arith ops are unnecessary and a pain, because of "++"
--- 231,237 ----
  ;; will only work when there won't be a preceding " or / before the sought /
  ;; to foul things up.
  (defconst c-awk-non-arith-op-bra-re
!   "[[\({&=:!><,?;'~|]")
  ;;   Matches an opening BRAcket, round or square, or any operator character
  ;; apart from +,-,/,*,%.  For the purpose at hand (detecting a / which is a
  ;; regexp bracket) these arith ops are unnecessary and a pain, because of "++"
***************
*** 242,247 ****
--- 242,257 ----
  ;; bracket, in a context where an immediate / would be a division sign.  This
  ;; will only work when there won't be a preceding " or / before the sought /
  ;; to foul things up.
+ (defconst c-awk-pre-exp-alphanum-kwd-re
+   (concat "\\(^\\|[^_\n\r]\\)\\<"
+ 	  (regexp-opt '("print" "return" "case") t)
+ 	  "\\>\\([^_\n\r]\\|$\\)"))
+ ;;   Matches all AWK keywords which can precede expressions (including
+ ;; /regexp/).
+ (defconst c-awk-kwd-regexp-sign-re
+   (concat c-awk-pre-exp-alphanum-kwd-re c-awk-neutrals*-re "/"))
+ ;;   Matches a piece of AWK buffer ending in <kwd> /, where <kwd> is a keyword
+ ;; which can precede an expression.
  
  ;; REGEXPS USED FOR FINDING THE POSITION OF A "virtual semicolon"
  (defconst c-awk-_-harmless-nonws-char-re "[^#/\"\\\\\n\r \t]")
***************
*** 721,729 ****
      (goto-char anchor)
      ;; Analyze the line to find out what the / is.
      (if (if anchor-state-/div
!             (not (search-forward-regexp c-awk-regexp-sign-re (1+ /point) t))
!           (search-forward-regexp c-awk-div-sign-re (1+ /point) t))
!         ;; A division sign.
  	(progn (goto-char (1+ /point)) nil)
        ;; A regexp opener
        ;; Jump over the regexp innards, setting the match data.
--- 731,740 ----
      (goto-char anchor)
      ;; Analyze the line to find out what the / is.
      (if (if anchor-state-/div
! 	    (not (search-forward-regexp c-awk-regexp-sign-re (1+ /point) t))
! 	  (and (not (search-forward-regexp c-awk-kwd-regexp-sign-re (1+ /point) t))
! 	       (search-forward-regexp c-awk-div-sign-re (1+ /point) t)))
! 	;; A division sign.
  	(progn (goto-char (1+ /point)) nil)
        ;; A regexp opener
        ;; Jump over the regexp innards, setting the match data.


> Leo

-- 
Alan Mackenzie (Nuremberg, Germany).