- (char-ci=? char[1] char[2])procedure
- (char-ci<? char[1] char[2])procedure
- (char-ci>? char[1] char[2])procedure
- (char-ci<=? char[1] char[2])procedure
- (char-ci>=? char[1] char[2])procedure
These procedures are similar to char=? et cetera, but they treat upper case and lower case letters as the same. For example, (char-ci=? #\A #\ a) returns #t. Some implementations may generalize these procedures to take more than two arguments, as with the corresponding numerical predicates.