The 'characterp' predicate function tests if 'expr' evaluates to a
character.
(characterp #\a) => T ; character (setq a #\b) => #\b (characterp a) => T ; evaluates to a character (characterp "a") => NIL ; string (characterp '(a b c)) => NIL ; list (characterp 1) => NIL ; integer (characterp 1.2) => NIL ; float (characterp 'a) => NIL ; symbol (characterp #(0 1 2)) => NIL ; array (characterp nil) => NIL ; NIL
See also: