characterp object => generalized-boolean
object—an object.
generalized-boolean—a generalized boolean.
Returns true if object is of type character; otherwise, returns false.
(characterp #\a) => true
(characterp 'a) => false
(characterp "a") => false
(characterp 65.) => false
(characterp #\Newline) => true
;; This next example presupposes an implementation
;; in which #\Rubout is an implementation-defined character.
(characterp #\Rubout) => true
character (type and function), typep
(characterp object) == (typep object 'character)