Re: (interactive) and &optional

[Jean Louis]

* Dr Rainer Woitok <rainer.woitok@gmail.com> [2023-03-23 22:12]:
> Am I really expected in a function that is both,  callable from Lisp and
> via "M-x", to code something along the lines of
> 
>    (cond ((or (null arg) (string-empty-p arg)) 'default-val)
>          (arg))
> 
> to check whether or not an optional argument has been passed?  Are there
> any more elegant ways to achieve this?

I do not like involving `interactive' at all, so I do the handling by
providing optional argument and telling function to check for it, or
ask for it.

(defun search-something (&optional query)
  "Search something by using QUERY."
  (interactive)
  (let* ((query (or query (read-from-minibuffer "Query: "))))
    (do-the-search query)))

-- 
Jean

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