Optional arg via lambda

Optional arg via lambda

[Sebastien Vauban]

Hello,

In my config, I have written this to check whether Org 8 is installed when
trying to call the "export dispatcher" (bound, here, to `C-x C-e').

--8<---------------cut here---------------start------------->8---
    (define-key org-mode-map
      (kbd "C-c C-e")
      (lambda ()
        (interactive)
        (if (fboundp 'org-export-dispatch)
            (org-export-dispatch)
          (message "Upgrade to Org 8!"))))
--8<---------------cut here---------------end--------------->8---

However, the above code drops the optional `C-u' which we can use when calling
`org-export-dispatch'. IOW, `C-u C-x C-e' does the same as `C-x C-e'.

I've tried adding an optional arg to the `lambda' and to pass it to the funcall
of `org-export-dispatch', as shown here:

--8<---------------cut here---------------start------------->8---
    (define-key org-mode-map
      (kbd "C-c C-e")
      (lambda (&optional arg)
        (interactive)
        (if (fboundp 'org-export-dispatch)
            (progn
              (message "arg: %s" arg)
              (funcall 'org-export-dispatch arg))
          (message "Upgrade to Org 8!"))))
--8<---------------cut here---------------end--------------->8---

But this does not work: `org-export-dispatch' is well called when pressing both
`C-x C-e' and `C-u C-x C-e', but the `C-u' is never passed along to the
original `org-export-dispatch' function.

What am I missing?

Best regards,
  Seb

-- 
Sebastien Vauban

Re: Optional arg via lambda

[Thorsten Jolitz]

"Sebastien Vauban" <sva-news@mygooglest.com>
writes:

> Hello,
>
> In my config, I have written this to check whether Org 8 is installed
> when trying to call the "export dispatcher" (bound, here, to `C-x
> C-e').
>
>     (define-key org-mode-map
>       (kbd "C-c C-e")
>       (lambda ()
>         (interactive)
>         (if (fboundp 'org-export-dispatch)
>             (org-export-dispatch)
>           (message "Upgrade to Org 8!"))))
>
> However, the above code drops the optional `C-u' which we can use when
> calling `org-export-dispatch'. IOW, `C-u C-x C-e' does the same as
> `C-x C-e'.
>
> I've tried adding an optional arg to the `lambda' and to pass it to
> the funcall of `org-export-dispatch', as shown here:
>
>     (define-key org-mode-map
>       (kbd "C-c C-e")
>       (lambda (&optional arg)
>         (interactive)
>         (if (fboundp 'org-export-dispatch)
>             (progn
>               (message "arg: %s" arg)
>               (funcall 'org-export-dispatch arg))
>           (message "Upgrade to Org 8!"))))
>
> But this does not work: `org-export-dispatch' is well called when
> pressing both `C-x C-e' and `C-u C-x C-e', but the `C-u' is never
> passed along to the original `org-export-dispatch' function.
>
> What am I missing?

does
      ,------------------------
      | (lambda (&optional arg)
      |   (interactive "P") ...
      `------------------------

make a difference?

-- 
cheers,
Thorsten

Re: Optional arg via lambda

[Sebastien Vauban]

Hi Thorsten,

Thorsten Jolitz wrote:
>> I've tried adding an optional arg to the `lambda' and to pass it to
>> the funcall of `org-export-dispatch', as shown here:
>>
>>     (define-key org-mode-map
>>       (kbd "C-c C-e")
>>       (lambda (&optional arg)
>>         (interactive)
>>         (if (fboundp 'org-export-dispatch)
>>             (progn
>>               (message "arg: %s" arg)
>>               (funcall 'org-export-dispatch arg))
>>           (message "Upgrade to Org 8!"))))
>>
>> But this does not work: `org-export-dispatch' is well called when
>> pressing both `C-x C-e' and `C-u C-x C-e', but the `C-u' is never
>> passed along to the original `org-export-dispatch' function.
>>
>> What am I missing?
>
> does
>       ,------------------------
>       | (lambda (&optional arg)
>       |   (interactive "P") ...
>       `------------------------
>
> make a difference?

Of course, it does!

Thanks for spotting this 3-char bug...

Best regards,
  Seb

-- 
Sebastien Vauban