limit input allowed by read-from-minibuffer?

limit input allowed by read-from-minibuffer?

[bturnip]

I want to prompt for a value in the minibuffer and only accept the
input if it matches one of the choices presented in my prompt string.
How do I do this?

(defun example()
  (interactive)
  (setq read_method(read-from-minibuffer "Read Method?
[<,>,>>,+<,+>,+>>] " nil nil nil nil "<"))
)

Re: limit input allowed by read-from-minibuffer?

[B. T. Raven]

"bturnip" <bturnip@gmail.com> wrote in message
news:1140730760.877986.48650@i39g2000cwa.googlegroups.com...
> I want to prompt for a value in the minibuffer and only accept the
> input if it matches one of the choices presented in my prompt string.
> How do I do this?
>
> (defun example()
>   (interactive)
>   (setq read_method(read-from-minibuffer "Read Method?
> [<,>,>>,+<,+>,+>>] " nil nil nil nil "<"))
> )
>

 (defun example()
   (interactive)
   (setq rm '("" "<" ">" ">>" "+<" "+>" "+>>"))
   (while (progn
       (setq read_method(read-from-minibuffer "Read Method?
[<,>,>>,+<,+>,+>>] " nil nil nil nil "<"))
    (not (member read_method rm))))

 )

I haven't tested this but something close to it should work. You have to
look for the null string because that's what will  be bound to your
'read_method variable if you just press enter. It will then be a synonym
for "<"

Ed

Re: limit input allowed by read-from-minibuffer?

[bturnip]

Thanks!  That did the trick.  I removed the option to just press enter-
I am going to have to do a little more work to figure out that part.

limit input allowed by read-from-minibuffer?

[bturnip]

I want to prompt for a value in the minibuffer and only accept the
input if it matches one of the choices presented in my prompt string.
How do I do this?

(defun example()
  (interactive)
  (setq read_method(read-from-minibuffer "Read Method?
[<,>,>>,+<,+>,+>>] " nil nil nil nil "<"))
)

RE: limit input allowed by read-from-minibuffer?

[Drew Adams]

    I want to prompt for a value in the minibuffer and only accept the
    input if it matches one of the choices presented in my prompt string.
    How do I do this?

    (defun example()
      (interactive)
      (setq read_method(read-from-minibuffer "Read Method?
    [<,>,>>,+<,+>,+>>] " nil nil nil nil "<")))

You want `completing-read', not `read-from-minibuffer'. That will: 1) let
users complete their input to any of the possible values, and 2) require
that their input be one of those values. Use non-nil for the REQUIRE-MATCH
argument.