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Returns
#t
if the specified characters are have the appropriate order relationship to one another; otherwise returns#f
. The-ci
procedures don't distinguish uppercase and lowercase letters.Character ordering follows these portability rules:
- The digits are in order; for example,
(char<? #\0 #\9)
returns#t
.- The uppercase characters are in order; for example,
(char<? #\A #\B)
returns#t
.- The lowercase characters are in order; for example,
(char<? #\a #\b)
returns#t
.MIT/GNU Scheme uses a specific character ordering, in which characters have the same order as their corresponding integers. See the documentation for
char->integer
for 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.