Re: HOW TO GIVE A DEFAULT TO A TRULY INTERACTIVE FUNCTION

[Edi Weitz]

gnuist006@hotmail.com (gnuist006) writes:

> (defun demo (&optional number)
> "Demo of an     optional argument of the function."
> (interactive "nEnter a number:")
> (setq defaultval 5)
> (if (null number) (setq number defaultval))
> (insert (format "%s" number))
> )                                        (demo)                       
>            ; works due to optional argument
> 
> I want the default to work on the command line also.
> They say emacs is customizable. OK it is if you only want to do what
> it
> can do, and never try to do what you want to do.
> 
> I want to invoke it on command line ie M-x demo
> It comes and says
> Enter a number:_
> 
> I prefer it display the default 5 in the message and there is
> SINGLE instance of 5 in the function. ie using defaultval.
> 
> If this cannot do this and you were all lying to yourself that
> emacs is customizable, infinitely extensible, then I atleast want
> quick fix for this.
> 
> When I hit RTN after it begs for number once, it go away and use
> defaultval and stop buggin me.
> 
> At present it does not stap and keeps bugging till I enter 5.
> Why do I have to remember the default when I am giving it that much
> money?

This guy is obviously a troll who doesn't deserve an answer but for
the sake of others who might read this:

  (require 'cl)

  (defun* bar (&optional (default 5))
    (let* ((default-string (format "%s" default))
           (string (read-string "Number: "
                                default-string
                                nil
                                default-string)))
      ;; needs check for wrong input
      (list (string-to-number string))))
  
  (defun foo (n)
    (interactive
     (bar 42))
    (insert (format "%s" (* 3 n))))
  
I'm sure the real Emacs experts know better ways to do this, I just
wanted to show that it's doable.

Edi.