[Emacs-diffs] master 8bef7b6 2/2: Only show "Back" when the marker stack is non-empty

[Dmitry Gutov]

branch: master
commit 8bef7b6ad1775124eeed81acf46551c0fc3aa75e
Author: Dmitry Gutov <address@hidden>
Commit: Dmitry Gutov <address@hidden>

    Only show "Back" when the marker stack is non-empty
    
    * lisp/menu-bar.el (menu-bar-goto-menu): Use it.
    
    * lisp/progmodes/xref.el (xref-marker-stack-empty-p): New function.
---
 lisp/ChangeLog         |    6 ++++++
 lisp/menu-bar.el       |    1 +
 lisp/progmodes/xref.el |    4 ++++
 3 files changed, 11 insertions(+), 0 deletions(-)

diff --git a/lisp/ChangeLog b/lisp/ChangeLog
index 34e22af..49640f8 100644
--- a/lisp/ChangeLog
+++ b/lisp/ChangeLog
@@ -1,5 +1,11 @@
 2015-01-03  Dmitry Gutov  <address@hidden>
 
+       * progmodes/xref.el (xref-marker-stack-empty-p): New function.
+
+       * menu-bar.el (menu-bar-goto-menu): Use it.
+
+2015-01-03  Dmitry Gutov  <address@hidden>
+
        * progmodes/xref.el (xref--window-configuration): New variable.
        (xref-show-location-at-point): New command.
        (xref--restore-window-configuration): New function.
diff --git a/lisp/menu-bar.el b/lisp/menu-bar.el
index 7d7e466..67cb327 100644
--- a/lisp/menu-bar.el
+++ b/lisp/menu-bar.el
@@ -381,6 +381,7 @@
 
     (bindings--define-key menu [xref-pop]
       '(menu-item "Back" xref-pop-marker-stack
+                  :visible (not (xref-marker-stack-empty-p))
                   :help "Back to the position of the last search"))
 
     (bindings--define-key menu [xref-apropos]
diff --git a/lisp/progmodes/xref.el b/lisp/progmodes/xref.el
index cb331e1..7bc6500 100644
--- a/lisp/progmodes/xref.el
+++ b/lisp/progmodes/xref.el
@@ -301,6 +301,10 @@ backward."
       (let ((marker (ring-remove ring)))
         (set-marker marker nil nil)))))
 
+(defun xref-marker-stack-empty-p ()
+  "Return t if the marker stack is empty; nil otherwise."
+  (ring-empty-p xref--marker-ring))
+
 
 (defun xref--goto-location (location)
   "Set buffer and point according to xref-location LOCATION."