Trapping Quit from x-popup-menu

Trapping Quit from x-popup-menu

[Tim Johnson]

Using 
GNU Emacs 24.3.1 (x86_64-pc-linux-gnu, GTK+ Version 3.4.2)
on Ubuntu 12.04

Here is a code snippet :

;; ---------------------------------------------------------
(let ((menu (tj-dir-menu curdir get-hidden))
	choice nextdir
	(default curdir))
    (setq choice
	  (x-popup-menu (list '(0 0) (selected-window)) menu))
    (message (concat "choice: " choice))
;; ---------------------------------------------------------

If I quit x-popup-menu without making a selection, than the rest of
the code in the defun - beginning with 

  (message (concat "choice: " choice)

is not executed. 

What is the proper way to trap the call to x-popup-menu so that I
can have some sort of a default value for 'choice?

Thanks
-- 
Tim 
tim at tee jay forty nine dot com or akwebsoft dot com
http://www.akwebsoft.com, http://www.tj49.com

Re: Trapping Quit from x-popup-menu

[Michael Heerdegen]

Tim Johnson <tim@akwebsoft.com> writes:

> ;; ---------------------------------------------------------
> (let ((menu (tj-dir-menu curdir get-hidden))
> 	choice nextdir
> 	(default curdir))
>     (setq choice
> 	  (x-popup-menu (list '(0 0) (selected-window)) menu))
>     (message (concat "choice: " choice))
> ;; ---------------------------------------------------------
>
> If I quit x-popup-menu without making a selection, than the rest of
> the code in the defun - beginning with 
>
>   (message (concat "choice: " choice)
>
> is not executed. 
>
> What is the proper way to trap the call to x-popup-menu so that I
> can have some sort of a default value for 'choice?

If you cannot/don't want to use a mouse button event as position
argument of `x-popup-menu` (as it is described in the docstring and
prevents the function from signaling quit), catch the quit signal
with condition-case:

    (condition-case nil
        (x-popup-menu ...)
      ((quit) a-default-value))


Michael

Re: Trapping Quit from x-popup-menu

[Tim Johnson]

* Michael Heerdegen <michael_heerdegen@web.de> [140629 12:58]:
> Tim Johnson <tim@akwebsoft.com> writes:
> 
> > ;; ---------------------------------------------------------
> > (let ((menu (tj-dir-menu curdir get-hidden))
> > 	choice nextdir
> > 	(default curdir))
> >     (setq choice
> > 	  (x-popup-menu (list '(0 0) (selected-window)) menu))
> >     (message (concat "choice: " choice))
> > ;; ---------------------------------------------------------
> >
> > If I quit x-popup-menu without making a selection, than the rest of
> > the code in the defun - beginning with 
> >
> >   (message (concat "choice: " choice)
> >
> > is not executed. 
> >
> > What is the proper way to trap the call to x-popup-menu so that I
> > can have some sort of a default value for 'choice?
> 
> If you cannot/don't want to use a mouse button event as position
> argument of `x-popup-menu` (as it is described in the docstring and
> prevents the function from signaling quit), catch the quit signal
> with condition-case:
> 
>     (condition-case nil
>         (x-popup-menu ...)
>       ((quit) a-default-value))
  Thanks Michael. That is exactly what I was looking for.
  On a related note, can you tell me how to use help to get a list
  of standard errors?

  I can see documentation at
  http://www.chemie.fu-berlin.de/chemnet/use/info/elisp/elisp_40.html#SEC592
  But don't know how to invoke it from emacs itself.

  Thanks again
-- 
Tim 
tim at tee jay forty nine dot com or akwebsoft dot com
http://www.akwebsoft.com, http://www.tj49.com

RE: Trapping Quit from x-popup-menu

[Drew Adams]

> can you tell me how to use help to get a list of standard errors?
> I can see documentation at
> http://www.chemie.fu-berlin.de/chemnet/use/info/elisp/elisp_40.html#SEC592
> But don't know how to invoke it from emacs itself.

C-h i m elisp RET

i standard errors RET

In Info, `i' is your friend.  It looks things up in the index.

Re: Trapping Quit from x-popup-menu

[Michael Heerdegen]

Drew Adams <drew.adams@oracle.com> writes:

> > can you tell me how to use help to get a list of standard errors?
> > I can see documentation at
> > http://www.chemie.fu-berlin.de/chemnet/use/info/elisp/elisp_40.html#SEC592
> > But don't know how to invoke it from emacs itself.
>
> C-h i m elisp RET
>
> i standard errors RET
>
> In Info, `i' is your friend.  It looks things up in the index.

Exactly.  Or use g to search the nodes.  You can also isearch (C-s) through
the whole manual.


Michael.

Re: Trapping Quit from x-popup-menu

[Eli Zaretskii]

> From: Michael Heerdegen <michael_heerdegen@web.de>
> Date: Mon, 30 Jun 2014 17:33:56 +0200
> 
> > In Info, `i' is your friend.  It looks things up in the index.
> 
> Exactly.  Or use g to search the nodes.  You can also isearch (C-s) through
> the whole manual.

In addition, in a good manual every node name that is "important"
(i.e. it is a phrase one might want to look up) should also appear in
the index.  So theoretically, you need only 'i' (and report as
potential bugs any nodes that deviate from this rule).

Re: Trapping Quit from x-popup-menu

[Tim Johnson]

* Tim Johnson <tim@akwebsoft.com> [140629 16:11]:
<...>   Thanks Michael. That is exactly what I was looking for.
>   On a related note, can you tell me how to use help to get a list
>   of standard errors?
> 
>   I can see documentation at
>   http://www.chemie.fu-berlin.de/chemnet/use/info/elisp/elisp_40.html#SEC592
>   But don't know how to invoke it from emacs itself.
    Thanks to all for answers on this related question.
	cheers
	"""Teach a man to fish ... """
-- 
Tim 
tim at tee jay forty nine dot com or akwebsoft dot com
http://www.akwebsoft.com, http://www.tj49.com