bug#9511: Moving the point to / with C-M-f and C-M-b when reading a filename from minibuffer

[Masatake YAMATO <yamato@redhat.com>]

This is a request for merge a patch to official GNU Emacs source tree.
Following patch adds a function to move the point to / with
C-M-f and C-M-b when reading a filename from minibuffer.
See also the thread at http://lists.gnu.org/archive/html/emacs-devel/2011-09/msg00155.html


2011-09-15  Masatake YAMATO  <yamato@redhat.com>

	* minibuffer.el (minibuffer-local-filename-syntax): New variable.
	(read-file-name-default): Install the syntax table.

=== modified file 'lisp/minibuffer.el'
--- lisp/minibuffer.el	2011-09-02 00:36:58 +0000
+++ lisp/minibuffer.el	2011-09-15 06:27:34 +0000
@@ -1997,6 +1997,31 @@
   (funcall (or read-file-name-function #'read-file-name-default)
            prompt dir default-filename mustmatch initial predicate))
 
+(defvar minibuffer-local-filename-syntax
+  (let ((table (make-syntax-table))
+	(punctuation (car (string-to-syntax "."))))
+    ;; Convert all punctuation entries to symbol.
+    (map-char-table (lambda (cc syntax)
+		      (when (and syntax
+				 (eq (car syntax)
+				     punctuation))
+			(let* ((cons? (consp cc))
+			       (begin (if cons? (car cc) cc))
+			       (end (if cons? (cdr cc) begin))
+			       (c begin))
+			  (while (<= c end)
+			    (modify-syntax-entry c "_" table)
+			    (setq c (1+ c))))))
+		    table)
+    (mapc
+     (lambda (c)
+       (modify-syntax-entry c "." table))
+     '(?/
+       ?: ?\\
+       ))
+    table)
+  "Syntax table to be used in minibuffer for reading file name.")
+
 ;; minibuffer-completing-file-name is a variable used internally in minibuf.c
 ;; to determine whether to use minibuffer-local-filename-completion-map or
 ;; minibuffer-local-completion-map.  It shouldn't be exported to Elisp.
@@ -2065,7 +2090,9 @@
                                (lambda ()
                                  (with-current-buffer
                                      (window-buffer (minibuffer-selected-window))
-				   (read-file-name--defaults dir initial)))))
+				   (read-file-name--defaults dir initial))))
+			  (set-syntax-table minibuffer-local-filename-syntax)
+			  )
                       (completing-read prompt 'read-file-name-internal
                                        pred mustmatch insdef
                                        'file-name-history default-filename)))