Re: elisp - only accepting input of known values

[Pascal J. Bourguignon]

Gary <help-gnu-emacs@garydjones.name> writes:

> Is it somehow possible to accept input from a set of known values (and
> only those values), possibly based on regex but I'm not married to that
> idea?

Yes, with completing-read, you can define the valid inputs.

For example: 

(defun get-fruit-list () '(apple banana orange))

(let ((fruit nil))
  (list
    (completing-read 
     "Fruit: "
     (mapcar (lambda (x) (cons x nil)) (get-fruit-list)) ; collection
     (lambda (selection) (setq fruit (car selection)))  ; predicate
     t ; require-match!
     )
   fruit))

--> ("orange" orange)

-- 
__Pascal Bourguignon__                     http://www.informatimago.com/
A bad day in () is better than a good day in {}.