awful.menu: support for access keys

You can define a menuitem like before:

awful.menu({ items = { { "&awesome", myawesomemenu,
	 		    beautiful.awesome_icon },
                       { "open &terminal", terminal },
	   })

and the letters following the ampersand in itemname can be used as
access key. (at least former fvwm users might find this familiar)

When there are submenus open awesome ascends during the search from the
current menu to the top level menu.

The access key is shown underlined.

There is no warning for multiple used keys, only the first one found
gets the price.

Signed-off-by: Julien Danjou <julien@danjou.info>

lib/awful/menu.lua.in

@@ -8,6 +8,7 @@
 -- Grab environment we need
 local pairs = pairs
 local table = table
+local string = string
 local type = type
 local setmetatable = setmetatable
 local wibox = wibox
@@ -153,6 +154,18 @@ local function item_enter(menu, num, mouse_event)
     end
 end
 
+local function check_access_key(menu, key)
+   for i, item in pairs(menu.items) do
+      if item.akey == key then
+	 exec(menu, i)
+	 return
+      end
+   end
+   if menu.parent then
+      check_access_key(menu.parent, key)
+   end
+end
+
 local function grabber(mod, key, event)
     if event == "release" then
        return true
@@ -171,6 +184,8 @@ local function grabber(mod, key, event)
         cur_menu:hide()
     elseif util.table.hasitem(menu_keys.close, key) then
         get_parents(cur_menu):hide()
+    else
+        check_access_key(cur_menu, key)
     end
    
     return true
@@ -192,7 +207,11 @@ local function add_item(data, num, item_info)
 
     -- Create the item label widget
     local label = widget({ type = "textbox" })
-    label.text = item_info[1]
+    local key = ''
+    label.text = string.gsub(item_info[1], "&(%w)", function (l)
+						        key= string.lower(l)
+						        return "<u>"..l.."</u>"
+						    end, 1)
     -- Set icon if needed
     local iconbox
     if item_info[3] then
@@ -245,7 +264,7 @@ local function add_item(data, num, item_info)
     item.height = label:extents().height + 2
     item.ontop = true
 
-    return { wibox = item, cmd = item_info[2] }
+    return { wibox = item, akey= key, cmd = item_info[2] }
 end
 
 --- Build a popup menu with running clients and shows it.