Character ordering follows these portability rules:
- The digits are in order; for example,
(char<? #\0 #\9)returns
- The uppercase characters are in order; for example,
(char<? #\A #\B)returns
- The lowercase characters are in order; for example,
(char<? #\a #\b)returns
MIT/GNU Scheme uses a specific character ordering, in which characters have the same order as their corresponding integers. See the documentation for
char->integerfor further details.
Note: Although character objects can represent all of Unicode, the model of alphabetic case used covers only ASCII letters, which means that case-insensitive comparisons and case conversions are incorrect for non-ASCII letters. This will eventually be fixed.