Re: Shift selection using interactive spec

[Juri Linkov <juri@jurta.org>]

>     As I understand the purpose of this feature is practically to move
>     the last expression of the command's body that usually is written as
>
> 	(if (interactive-p)
> 	    (message "Result of this command is %.0f" return-value)
> 	  (format "%.0f" return-value))
>
> You have the right idea in mind for what the code would be trying to
> do.  But code like that would be a strange way to write it, and in
> practice does seem to occur much if at all.  The way I would envision
> this is more like
>
> 	(if interactive-call
> 	    (message "Result of this command is %.0f" return-value))
>    	return-value)
>
> where `interactive-call' is an argument initialized to non-nil
> for an interactive call.
>
> The job of the second arg to `interactive', that I've proposed, would
> be to control how to generate the message in the interactive case.

Then the second arg to `interactive' could be just a lambda
with one argument with the value this function returns, e.g.

(defun command ()
  (interactive
    nil
    (lambda (ret-val)
      (message "Result of this command is %.0f" ret-val)))
  ...
  (let ((return-value ...))
    ...
    return-value))

-- 
Juri Linkov
http://www.jurta.org/emacs/