hexdigit

[variable] lower-case

[variable] upper-case

[variable] alphabetic

[variable] numeric

[variable] alphanumeric

[variable] punctuation

[variable] graphic

[variable] printing

[variable] control

[variable] blank

[variable] whitespace

[variable] hexdigit

Scheme48: predefined character sets.

SRFI-14 defines char-set:lower-case, char-set:upper-case, char-set:letter, char-set:digit, char-set:letter+digit, char-set:punctuation, char-set:graphic, char-set:printing, char-set:iso-control, char-set:blank, char-set:whitespace and char-set:hex-digit.