read-char-choice
read-char-choice is a compiled Lisp function in `subr.el
'.
(read-char-choice PROMPT CHARS &optional INHIBIT-KEYBOARD-QUIT)
Read and return one of CHARS, prompting for PROMPT.
Any input that is not one of CHARS is ignored.
If optional argument INHIBIT-KEYBOARD-QUIT is non-nil, ignore
keyboard-quit events while waiting for a valid input.