Standard Character Procedure.
Get ch's position in the collating
sequence.
(integer->charn)
Standard Character Procedure.
Get the nth character in the
collating sequence.
(char-downcasech)
Standard Character Procedure.
If ch is an upper-case character
(#\A, #\B, ... #\Z, in ASCII; potentially other characters in other
character sets), return the corresponding lower-case
character. Otherwise, return the same character.
(char-upcasech)
Standard Character Procedure.
If ch is a lower-case character
(#\a, #\b, ... #\z, in ASCII; potentially other characters in other
character sets), return the corresponding upper-case
character (#\A for #\a, #\B for #\b, etc.). Otherwise, return
the same character.
Character Predicates
(char?val)
Standard Character Predicate.
Determine if val is a character.
(char-alphabetic?ch)
Standard Character Predicate.
Determine if ch (which must be a
character) is an alphabetic character (in English, #\a, #\b, ... #\z,
#\A, #\B, ...., #\Z).
(char-numeric?ch)
Standard Character Predicate.
Determine if ch (which must be a
character) represents a digit in a number (traditionally,
#\0, #\1, ... #\9, although other systems have different
numeric characters).
(char-whitespace?ch)
Standard Character Predicate.
Determine if ch (which must be a
character) represents a whitespace character, such as a space,
a tab, or a newline.
(char-lower-case?ch)
Standard Character Predicate.
Determine if ch (which must be a
character) represents a lower-case character
(in English, #\a, #\b, ... #\z).
(char-upper-case?ch)
Standard Character Predicate.
Determine if ch (which must be a
character) represents an upper-case character
(in English, #\A, #\B, ... #\Z).
Comparing Characters
(char<?ch1ch2)
Standard Character Comparator.
Determine if ch1 precedes
ch2 in the collating sequence.
Both ch1 and ch2
must be characters.
(char<=?ch1ch2)
Standard Character Comparator.
Determine if ch1 equals
ch2 or if
ch1 precedes
ch2 in the collating sequence.
Both ch1 and ch2
must be characters.
(char=?ch1ch2)
Standard Character Comparator.
Determine if ch1 and
ch2 are the same. Both
ch1 and ch2 must
be characters.
(char>=?ch1ch2)
Standard Character Comparator.
Determine if ch1 and ch2
are equal or if ch1 follows
ch2 in the collating sequence.
Both ch1 and ch2
must be characters.
(char>?ch1ch2)
Standard Character Comparator.
Determine if ch1 follows
ch2 in the collating sequence.
Both ch1 and ch2
must be characters.
(char-ci<?ch1ch2)
Standard Character Comparator.
If both ch1 and ch2
are alphabetic characters (letters), determine if
ch1 naturally precedes
ch2, ignoring case.
If either is not alphabetic, determine if ch1 precedes
ch2 in the collating sequence.
Both ch1 and ch2
must be characters.
(char-ci<=?ch1ch2)
Standard Character Comparator.
If both ch1 and ch2
are alphabetic characters (letters), determine if
ch1 naturally precedes or equals
ch2, ignoring case.
If either is not alphabetic, determine if ch1 equals
ch2 or if ch1 precedes
ch2 in the collating sequence.
Both ch1 and ch2
must be characters.
(char-ci=?ch1ch2)
Standard Character Comparator.
If both ch1 and ch2
are alphabetic characters (letters), determine if
ch1 and ch2 represent
the same letter, ignoring case.
If either is not alphabetic, determine if ch1 follows
ch2 in the collating sequence.
Both ch1 and ch2
must be characters.
(char-ci>=?ch1ch2)
Standard Character Comparator.
If both ch1 and ch2
are alphabetic characters (letters), determine if
ch1 naturally follows or equals
ch2, ignoring case. If either is not
alphabetic, determine if ch1 equals
ch2 or if ch1
follows ch2 in the collating sequence.
Both ch1 and ch2
must be characters.
(char-ci>?ch1ch2)
Standard Character Comparator.
If both ch1 and ch2
are alphabetic characters (letters), determine if
ch1 naturally follows
ch2, ignoring case.
If either is not alphabetic, determine if ch1 follows
ch2 in the collating sequence.
Both ch1 and ch2
must be characters.