Re: An interactive command definiftion

[Oliver Scholz <alkibiades@gmx.de>]

"Rodolfo Medina" <romeomedina@libero.it> writes:

[...]
> . Then I want to define a command, let's call it manage-my-weather,
> that prompts me the message:
>
> my-weather is now: sunshine. If it is okay, press enter; if you to change
> it, press c
>
> . Of course, if my-weather were rain, the message should be:
>
> my-weather is now: rain. If it is okay, press enter; if you to change it,
> press c
>
>
> . Then, after pressing c (and then enter, I suppose),
> manage-my-weather should prompt this new message:
>
> enter new value for my-weather
>
> , this way allowing me to change my-weather's value at my pleasure.
> Is it possible to do this, and how?

Instead of a string you may also put a lisp form into the interactive
specification; in that case the form, when evaluated, should return a
list of values for the argument list of the function. This provides
the freedom necessary to achieve what you want:

(defun manage-my-weather (input-char)
  (interactive
   (let ((prompt (format "my-weather is now: %s.  Press `c' to change."
			 my-weather)))
     (list (read-char prompt))))
  (when (eq input-char ?c)
    (setq my-weather
	  (intern (read-from-minibuffer "New weather: ")))))



    Oliver
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