5.5.4.6 Standard Character Sets
In order to make the use of the character set data type and procedures
useful, several predefined character set variables exist.
Currently, the contents of these character sets are recomputed upon a
successful setlocale call (see Locales) in order to reflect
the characters available in the current locale's codeset. For
instance, char-set:letter contains 52 characters under an ASCII
locale (e.g., the default C locale) and 117 characters under an
ISO-8859-1 (“Latin-1”) locale.
— Scheme Variable:
char-set:lower-case
— C Variable:
scm_char_set_lower_case
All lower-case characters.
— Scheme Variable:
char-set:upper-case
— C Variable:
scm_char_set_upper_case
All upper-case characters.
— Scheme Variable:
char-set:title-case
— C Variable:
scm_char_set_title_case
This is empty, because ASCII has no titlecase characters.
— Scheme Variable:
char-set:letter
— C Variable:
scm_char_set_letter
All letters, e.g. the union of char-set:lower-case and
char-set:upper-case.
— Scheme Variable:
char-set:digit
— C Variable:
scm_char_set_digit
All digits.
— Scheme Variable:
char-set:letter+digit
— C Variable:
scm_char_set_letter_and_digit
The union of char-set:letter and char-set:digit.
— Scheme Variable:
char-set:graphic
— C Variable:
scm_char_set_graphic
All characters which would put ink on the paper.
— Scheme Variable:
char-set:printing
— C Variable:
scm_char_set_printing
The union of char-set:graphic and char-set:whitespace.
— Scheme Variable:
char-set:whitespace
— C Variable:
scm_char_set_whitespace
All whitespace characters.
— Scheme Variable:
char-set:blank
— C Variable:
scm_char_set_blank
All horizontal whitespace characters, that is #\space and
#\tab.
— Scheme Variable:
char-set:iso-control
— C Variable:
scm_char_set_iso_control
The ISO control characters with the codes 0–31 and 127.
— Scheme Variable:
char-set:punctuation
— C Variable:
scm_char_set_punctuation
The characters !"#%&'()*,-./:;?@[\\]_{}
— Scheme Variable:
char-set:symbol
— C Variable:
scm_char_set_symbol
The characters $+<=>^`|~.
— Scheme Variable:
char-set:hex-digit
— C Variable:
scm_char_set_hex_digit
The hexadecimal digits 0123456789abcdefABCDEF.
— Scheme Variable:
char-set:ascii
— C Variable:
scm_char_set_ascii
All ASCII characters.
— Scheme Variable:
char-set:empty
— C Variable:
scm_char_set_empty
The empty character set.
— Scheme Variable:
char-set:full
— C Variable:
scm_char_set_full
This character set contains all possible characters.