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bug#26421: 25.1; Handling of prefix arg in menus
From: |
Drew Adams |
Subject: |
bug#26421: 25.1; Handling of prefix arg in menus |
Date: |
Sun, 9 Apr 2017 11:04:44 -0700 (PDT) |
emacs -Q
Evaluate this code:
(defvar menu-bar-foo-menu (make-sparse-keymap "Foo"))
(define-key global-map [menu-bar foo] (cons "Foo" menu-bar-foo-menu))
(define-key menu-bar-foo-menu [toto]
'(menu-item "Toto" forward-char
:visible
(progn
(message "PP: %S"
(and current-prefix-arg
(prefix-numeric-value current-prefix-arg)))
(and current-prefix-arg
(prefix-numeric-value current-prefix-arg)))))
(defvar bar-menu (make-sparse-keymap "Bar"))
(define-key menu-bar-foo-menu [bar] (cons "Bar" bar-menu))
(define-key bar-menu [foobar]
'(menu-item "XXX" forward-char
:visible
(progn
(message "PP: %S"
(and current-prefix-arg
(prefix-numeric-value current-prefix-arg)))
(and current-prefix-arg
(prefix-numeric-value current-prefix-arg)))))
Open *Messages* in another frame, so you can see messages there.
In the original frame, access menu Foo and submenu Bar, using (1) no
prefix arg, (2) a prefix arg introduced using `C-u', and (3) a prefix
arg introduced in another way, such as `M-2'.
The actual prefix arg you give is not employed in the :visible code
(same thing for :enable). Instead:
* For no prefix arg given, or for any prefix arg given other than by
using explicit `C-u', the value used by :visible is nil.
* For a prefix arg given using explicit `C-u', the value used by
:visible is 4.
That is, in the former case you see always "PP: nil" output, and for the
latter you see always "PP: 4" output.
This means that you cannot use the prefix arg in a menu-item test.
This should not be the case. (This problem is not new.)
In GNU Emacs 25.1.1 (x86_64-w64-mingw32)
of 2016-11-15
Windowing system distributor `Microsoft Corp.', version 6.1.7601
Configured using:
`configure --without-dbus --without-compress-install 'CFLAGS=-O2
-static -g3''
- bug#26421: 25.1; Handling of prefix arg in menus,
Drew Adams <=