cyclone/docs/api/scheme/char.md
2021-03-30 22:26:03 -04:00

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# Char Library
The `(scheme char)` library provides the procedures for dealing with characters.
For more information see the [R<sup>7</sup>RS Scheme Specification](../../r7rs.pdf).
- [`char-alphabetic?`](#char-alphabetic)
- [`char-ci<=?`](#char-ci)
- [`char-ci<?`](#char-ci-1)
- [`char-ci=?`](#char-ci-2)
- [`char-ci>=?`](#char-ci-3)
- [`char-ci>?`](#char-ci-4)
- [`char-downcase`](#char-downcase)
- [`char-foldcase`](#char-foldcase)
- [`char-lower-case?`](#char-lower-case)
- [`char-numeric?`](#char-numeric)
- [`char-upcase`](#char-upcase)
- [`char-upper-case?`](#char-upper-case)
- [`char-whitespace?`](#char-whitespace)
- [`digit-value`](#digit-value)
- [`string-ci<=?`](#string-ci)
- [`string-ci<?`](#string-ci-1)
- [`string-ci=?`](#string-ci-2)
- [`string-ci>=?`](#string-ci-3)
- [`string-ci>?`](#string-ci-4)
- [`string-downcase`](#string-downcase)
- [`string-foldcase`](#string-foldcase)
- [`string-upcase`](#string-upcase)
# char-alphabetic?
(char-alphabetic? c)
Return `#t` if `c` is alphabetic and `#f` otherwise.
# char-ci<=?
(char-ci<=? c1 c2 . cs)
Return `#t` if the results of converting all characters to the same case and passing the arguments to `char->integer` are monotonically increasing or equal.
# char-ci<?
(char-ci<? c1 c2 . cs)
Return `#t` if the results of converting all characters to the same case and passing the arguments to `char->integer` are respectively equal, monotonically increasing.
# char-ci=?
(char-ci=? c1 c2 . cs)
Return `#t` if the results of converting all characters to the same case and passing the arguments to `char->integer` are equal.
# char-ci>=?
(char-ci>=? c1 c2 . cs)
Return `#t` if the results of converting all characters to the same case and passing the arguments to `char->integer` are monotonically decreasing or equal.
# char-ci>?
(char-ci>? c1 c2 . cs)
Return `#t` if the results of converting all characters to the same case and passing the arguments to `char->integer` are monotonically decreasing.
# char-downcase
(char-downcase c)
Returns the lowercase equivalent of `c` if one exists, otherwise `c` is returned.
# char-foldcase
(char-foldcase c)
# char-lower-case?
(char-lower-case? c)
Return `#t` if `c` is lower case and `#f` otherwise.
# char-numeric?
(char-numeric? c)
Return `#t` if `c` is numeric and `#f` otherwise.
# char-upcase
(char-upcase c)
Returns the uppercase equivalent of `c` if one exists, otherwise `c` is returned.
# char-upper-case?
(char-upper-case? c)
Return `#t` if `c` is alphabetic and `#f` otherwise.
# char-whitespace?
(char-whitespace? c)
Return `#t` if `c` is whitespace and `#f` otherwise.
# digit-value
(digit-value c)
This procedure returns the numeric value (0 to 9) of its argument if it is a numeric digit (that is, if `char-numeric?` returns `#t`), or `#f` on any other character.
# string-ci<=?
(string-ci<=? s1 s2)
# string-ci<?
(string-ci<? s1 s2)
# string-ci=?
(string-ci=? s1 s2)
Returns `#t` if all of the given strings are equal using a case-insensitive comparison, and false otherwise.
# string-ci>=?
(string-ci>=? s1 s2)
# string-ci>?
(string-ci>? s1 s2)
# string-downcase
(string-downcase str)
Return a newly-allocated string with any uppercase characters converted to lowercase.
# string-foldcase
(string-foldcase str)
# string-upcase
(string-upcase str)
Return a newly-allocated string with any lowercase characters converted to uppercase.