Re: elisp - only accepting input of known values

[Tyler Smith]

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

> Tassilo Horn wrote:
>> Gary 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?
>>
>> What exactly do you mean with "input"?  Input to what?  A function?
>
> User input.

completing-read does this. The info file is here:

(info "(elisp)Minibuffer Completion")

The help reads, in part:

completing-read is a built-in function in `C source code'.

(completing-read PROMPT COLLECTION &optional PREDICATE REQUIRE-MATCH
INITIAL-INPUT HIST DEF INHERIT-INPUT-METHOD)

Read a string in the minibuffer, with completion.
PROMPT is a string to prompt with; normally it ends in a colon and a space.
COLLECTION can be a list of strings, an alist, an obarray or a hash table.
COLLECTION can also be a function to do the completion itself.
PREDICATE limits completion to a subset of COLLECTION.
See `try-completion' and `all-completions' for more details
 on completion, COLLECTION, and PREDICATE.

Tyler