Add new command 'vc-dir-mark-by-regexp'

* doc/emacs/maintaining.texi (VC Directory Commands): Document it.
* lisp/vc/vc-dir.el (vc-dir-mode-map): Bind it to `%'.
(vc-dir-mark-by-regexp): New command (bug#16460).

doc/emacs/maintaining.texi

@@ -1316,6 +1316,12 @@ point is on a directory entry, mark all files in that directory tree
 (@code{vc-dir-mark-all-files}).  With a prefix argument, mark all
 listed files and directories.
 
+@findex vc-dir-mark-by-regexp
+@item %
+You can use this command to mark files by regexp
+(@code{vc-dir-mark-by-regexp}).  If given a prefix, unmark files
+instead.
+
 @item G
 Add the file under point to the list of files that the VC should
 ignore (@code{vc-dir-ignore}).  For instance, if the VC is Git, it

etc/NEWS

@@ -1009,6 +1009,11 @@ info node.  This command only works for the Emacs and Emacs Lisp manuals.
 
 ** vc
 
++++
+*** New command '%' ('vc-dir-mark-by-regexp').
+This command marks files based on a regexp.  If given a prefix
+argument, unmark instead.
+
 ---
 *** 'C-x v v' on an unregistered file will now use the most specific backend.
 Previously, if you had an SVN-covered "~/" directory, and a Git-covered

lisp/vc/vc-dir.el

@@ -325,6 +325,7 @@ See `run-hooks'."
     (define-key map "U" #'vc-dir-unmark-all-files)
     (define-key map "\C-?" #'vc-dir-unmark-file-up)
     (define-key map "\M-\C-?" #'vc-dir-unmark-all-files)
+    (define-key map "%" #'vc-dir-mark-by-regexp)
     ;; Movement.
     (define-key map "n" #'vc-dir-next-line)
     (define-key map " " #'vc-dir-next-line)
@@ -750,6 +751,23 @@ share the same state."
 		(vc-dir-mark-file crt)))
 	    (setq crt (ewoc-next vc-ewoc crt))))))))
 
+(defun vc-dir-mark-by-regexp (regexp &optional unmark)
+  "Mark all files that match REGEXP.
+If UNMARK (interactively, the prefix), unmark instead."
+  (interactive "sMark files matching: \nP")
+  (ewoc-map
+   (lambda (filearg)
+     (when (and (not (vc-dir-fileinfo->directory filearg))
+                (eq (not unmark)
+                    (not (vc-dir-fileinfo->marked filearg)))
+                ;; We don't want to match on the part of the file
+                ;; that's above the current directory.
+                (string-match-p regexp (file-relative-name
+                                        (vc-dir-fileinfo->name filearg))))
+       (setf (vc-dir-fileinfo->marked filearg) (not unmark))
+       t))
+   vc-ewoc))
+
 (defun vc-dir-mark-files (mark-files)
   "Mark files specified by file names in the argument MARK-FILES.
 MARK-FILES should be a list of absolute filenames."