Greater-than test for characters
(char> x y) is true if and only if the character code of
x is greater than that of y. See char-code.
The guard for char> specifies that its arguments are characters.
Char> is a Common Lisp function. See any Common Lisp documentation
for more information.
(defun char> (x y)
(declare (xargs :guard (and (characterp x) (characterp y))))
(> (char-code x) (char-code y)))