(grep-highlight-matches): New defcustom.

(grep-regexp-alist): Add rule to highlight grep matches.
(grep-process-setup): Set env-vars GREP_OPTIONS and GREP_COLOR.

lisp/progmodes/grep.el

@@ -64,6 +64,21 @@ will be parsed and highlighted as soon as you try to move to them."
   :version "21.4"
   :group 'grep)
 
+(defcustom grep-highlight-matches t
+  "*Non-nil to use special markers to highlight grep matches.
+
+Some grep programs are able to surround matches with special
+markers in grep output.  Such markers can be used to highlight
+matches in grep mode.
+
+This option sets the environment variable GREP_COLOR to specify
+markers for highlighting and GREP_OPTIONS to add the --color
+option in front of any explicit grep options before starting
+the grep."
+  :type 'boolean
+  :version "21.4"
+  :group 'grep)
+
 (defcustom grep-scroll-output nil
   "*Non-nil to scroll the *grep* buffer window as output appears.
 
@@ -230,6 +245,23 @@ Notice that using \\[next-error] or \\[compile-goto-error] modifies
   '(("^\\(.+?\\)[:( \t]+\
 \\([0-9]+\\)\\([.:]?\\)\\([0-9]+\\)?\
 \\(?:-\\(?:\\([0-9]+\\)\\3\\)?\\.?\\([0-9]+\\)?\\)?[:) \t]" 1 (2 . 5) (4 . 6))
+    ("^\\(.+?\\)[:(]+\\([0-9]+\\)\\([:)]\\).*?\\(\033\\[01;41m\\)\\(.*?\\)\\(\033\\[00m\\)"
+     1 2
+     ((lambda ()
+        (setq compilation-error-screen-columns nil)
+        (- (match-beginning 5) (match-end 3) 8))
+      .
+      (lambda () (- (match-end 5) (match-end 3) 8)))
+     nil nil
+     (4 (list 'face nil 'invisible t 'intangible t))
+     (5 (list 'face compilation-column-face))
+     (6 (list 'face nil 'invisible t 'intangible t))
+     ;; highlight other matches on the same line
+     ("\\(\033\\[01;41m\\)\\(.*?\\)\\(\033\\[00m\\)"
+      nil nil
+      (1 (list 'face nil 'invisible t 'intangible t))
+      (2 (list 'face compilation-column-face) t)
+      (3 (list 'face nil 'invisible t 'intangible t))))
     ("^Binary file \\(.+\\) matches$" 1 nil nil 1))
   "Regexp used to match grep hits.  See `compilation-error-regexp-alist'.")
 
@@ -300,6 +332,10 @@ This variable's value takes effect when `grep-compute-defaults' is called.")
 (defun grep-process-setup ()
   "Setup compilation variables and buffer for `grep'.
 Set up `compilation-exit-message-function' and run `grep-setup-hook'."
+  (when grep-highlight-matches
+    ;; Modify `process-environment' locally bound in `compilation-start'
+    (setenv "GREP_OPTIONS" (concat (getenv "GREP_OPTIONS") " --color=always"))
+    (setenv "GREP_COLOR" "01;41"))
   (set (make-local-variable 'compilation-exit-message-function)
        (lambda (status code msg)
 	 (if (eq status 'exit)