Keyboard grabs

Keyboard grabs

[Richard Stallman]

Is someone working on making Emacs do a global grab
when it displays a menu?

Re: Keyboard grabs

[Jan D.]

> 
> Is someone working on making Emacs do a global grab
> when it displays a menu?

If no one is, I can do it.  

On a related note, is there a reason why Emacs
queues keyboard events while menus are mapped?  That is, if I click on
a menu, press "Hello world", and then clicks down the menu, the "Hello world"
is inserted into the current buffer.  I have never seen any application
doing anything like it.  Can that be removed?  I would suspect that
it can lead to surprises if keyboard shortcuts are implemented for menus.
If you hit the wrong key when a menu shortcut was intended, you don't want
that key to go into the buffer later when the menu dissapears.

	Jan D.

Re: Keyboard grabs

[Pavel Janík]

   From: "Jan D." <jan.h.d@swipnet.se>
   Date: Fri, 19 Apr 2002 22:24:30 +0200 (MEST)

Hi Jan,

   > On a related note, is there a reason why Emacs
   > queues keyboard events while menus are mapped?  That is, if I click on
   > a menu, press "Hello world", and then clicks down the menu, the "Hello world"
   > is inserted into the current buffer.

this is no longer true for about fifteen minutes ;-) I have committed
a patch which removes that. See my other e-mail.
-- 
Pavel Janík

Don't patch bad code - rewrite it.
                  --  The Elements of Programming Style (Kernighan & Plaugher)

Re: Keyboard grabs

[Jan D.]

>    > On a related note, is there a reason why Emacs
>    > queues keyboard events while menus are mapped?  That is, if I click on
>    > a menu, press "Hello world", and then clicks down the menu, the "Hello=
>  world"
>    > is inserted into the current buffer.
> 
> this is no longer true for about fifteen minutes ;-) I have committed
> a patch which removes that. See my other e-mail.

Cool, cvs up:ing now.

	Jan D.

Re: Keyboard grabs

[Richard Stallman]

    > Is someone working on making Emacs do a global grab
    > when it displays a menu?

    If no one is, I can do it.  

Nobody else is, so I would be grateful if you did that.

      Thus, a keyboard grab to prevent this is the only solution.
    It what other applications (X toolkits really) do.

ISTR that there was some disagreement about that question,
but if it is true that other X apps do a global grab,
please do use that solution.  It is good for Emacs to do
what is familiar.

But there should be a flag which controls whether to do the global
grab.  Perhaps the flag should be nil for an uninstalled Emacs.  That
is an easy way to arrange that the global grab will not occur when
debugging.

Re: Keyboard grabs

[Jan D.]

> But there should be a flag which controls whether to do the global
> grab.  Perhaps the flag should be nil for an uninstalled Emacs.  That
> is an easy way to arrange that the global grab will not occur when
> debugging.

I've installed keyboard grab.  I've used a C-variable x_menu_grab_keyboard
which one can set to zero to prevent the keyboard grab from the debugger.
I didn't get fancy with the install suggestion, after all, the grab only
causes problem if you suspend or stop Emacs while a menu is posted.  Surely
one can start Emacs from within the debugger in that case?

	Jan D.

Re: Keyboard grabs

[Richard Stallman]

    I didn't get fancy with the install suggestion, after all, the grab only
    causes problem if you suspend or stop Emacs while a menu is posted.  Surely
    one can start Emacs from within the debugger in that case?

Assume you did start Emacs from the debugger--if it hits a breakpoint
while a menu is posted, how do you type anything at the debugger?
Your console is hosed!  I've seen things like this happen with grabs
in Emacs before.

So I think it is important to have something that will help prevent
this problem case.  Testing for an uninstalled Emacs was the idea I
had.  Do you have another idea for a default criterion?

Re: Keyboard grabs

[Jan D.]

> 
>     I didn't get fancy with the install suggestion, after all, the grab only
>     causes problem if you suspend or stop Emacs while a menu is posted.  Surely
>     one can start Emacs from within the debugger in that case?
> 
> Assume you did start Emacs from the debugger--if it hits a breakpoint
> while a menu is posted, how do you type anything at the debugger?
> Your console is hosed!  I've seen things like this happen with grabs
> in Emacs before.
> 
> So I think it is important to have something that will help prevent
> this problem case.  Testing for an uninstalled Emacs was the idea I
> had.  Do you have another idea for a default criterion?
> 

I kind of assumed that if you are debugging and suspect you might end up
in this situation, you set the variable in the debugger before starting
Emacs.  If you forget this, you are hosed of course, so a default off
for uninstalled is a good idea.

What is the proper way to check for installed/uninstalled Emacs?

	Jan D.

Re: Keyboard grabs

[Richard Stallman]

    I kind of assumed that if you are debugging and suspect you might end up
    in this situation, you set the variable in the debugger before starting
    Emacs.  If you forget this, you are hosed of course, so a default off
    for uninstalled is a good idea.

    What is the proper way to check for installed/uninstalled Emacs?

Look at the value of installation-directory.  It is nil
for an installed Emacs.