char-set:punctuation

[variable] char-set:lower-case

[variable] char-set:upper-case

[variable] char-set:title-case

[variable] char-set:letter

[variable] char-set:digit

[variable] char-set:letter+digit

[variable] char-set:graphic

[variable] char-set:printing

[variable] char-set:whitespace

[variable] char-set:iso-control

[variable] char-set:punctuation

[variable] char-set:symbol

[variable] char-set:hex-digit

[variable] char-set:blank

[variable] char-set:ascii

[variable] char-set:empty

[variable] char-set:full

SRFI-14: predefined character sets.

Cf. Scheme48 has lower-case etc.