From a9bc137f5ec9d474b035afdbd0de9b0a5fe73c5e Mon Sep 17 00:00:00 2001
From: Stefan Monnier <monnier@iro.umontreal.ca>
Date: Tue, 3 Jun 2008 07:18:54 +0000
Subject: [PATCH] (perl-font-lock-syntactic-keywords): Try to be yet a bit more
 clever at distinguishing / from /.

---
 lisp/ChangeLog              |  5 +++++
 lisp/progmodes/perl-mode.el | 23 +++++++++++++++++++----
 2 files changed, 24 insertions(+), 4 deletions(-)

diff --git a/lisp/ChangeLog b/lisp/ChangeLog
index de57acf56b6..a58fc460289 100644
--- a/lisp/ChangeLog
+++ b/lisp/ChangeLog
@@ -1,3 +1,8 @@
+2008-06-03  Stefan Monnier  <monnier@iro.umontreal.ca>
+
+	* progmodes/perl-mode.el (perl-font-lock-syntactic-keywords): Try to be
+	yet a bit more clever at distinguishing / from /.
+
 2008-06-03  Kenichi Handa  <handa@m17n.org>
 
 	* Makefile.in (ELCFILES): Add $(lisp)/language/hanja-util.elc.
diff --git a/lisp/progmodes/perl-mode.el b/lisp/progmodes/perl-mode.el
index 22d9b488cc6..c92ac4252da 100644
--- a/lisp/progmodes/perl-mode.el
+++ b/lisp/progmodes/perl-mode.el
@@ -252,7 +252,7 @@ The expansion is entirely correct because it uses the C preprocessor."
 ;; <file*glob>
 (defvar perl-font-lock-syntactic-keywords
   ;; TODO: here-documents ("<<\\(\\sw\\|['\"]\\)")
-  '(;; Turn POD into b-style comments
+  `(;; Turn POD into b-style comments
     ("^\\(=\\)\\sw" (1 "< b"))
     ("^=cut[ \t]*\\(\n\\)" (1 "> b"))
     ;; Catch ${ so that ${var} doesn't screw up indentation.
@@ -267,12 +267,27 @@ The expansion is entirely correct because it uses the C preprocessor."
     ;; Be careful not to match "sub { (...) ... }".
     ("\\<sub\\(?:[[:space:]]+[^{}[:punct:][:space:]]+\\)?[[:space:]]*(\\([^)]+\\))"
      1 '(1))
-    ;; Regexp and funny quotes.
-    ("\\(?:[?:.,;=!~({[]\\|\\(^\\)\\)[ \t\n]*\\(/\\)"
+    ;; Regexp and funny quotes.  Distinguishing a / that starts a regexp
+    ;; match from the division operator is ...interesting.
+    ;; Basically, / is a regexp match if it's preceded by an infix operator
+    ;; (or some similar separator), or by one of the special keywords
+    ;; corresponding to builtin functions that can take their first arg
+    ;; without parentheses.  Of course, that presume we're looking at the
+    ;; *opening* slash.  We can mis-match the closing ones, because they are
+    ;; treated separately later in
+    ;; perl-font-lock-special-syntactic-constructs.
+    (,(concat "\\(?:\\(?:\\(?:^\\|[^$@&%[:word:]]\\)"
+              (regexp-opt '("split" "if" "unless" "until" "while" "split"
+                            "grep" "map" "not" "or" "and"))
+              "\\)\\|[?:.,;=!~({[]\\|\\(^\\)\\)[ \t\n]*\\(/\\)")
      (2 (if (and (match-end 1)
                  (save-excursion
                    (goto-char (match-end 1))
-                   (skip-chars-backward " \t\n")
+                   ;; Not 100% correct since we haven't finished setting up
+                   ;; the syntax-table before point, but better than nothing.
+                   (forward-comment (- (point-max)))
+                   (put-text-property (point) (match-end 2)
+                                      'jit-lock-multiline t)
                    (not (memq (char-before)
                               '(?? ?: ?. ?, ?\; ?= ?! ?~ ?\( ?\[)))))
             nil ;; A division sign instead of a regexp-match.
-- 
2.39.2