string-ci=?, string-ci<?, string-ci>?, string-ci<=?, string-ci>=? - case-insensitive string comparison

LIBRARY

(import (rnrs))                     ;R6RS
(import (rnrs unicode))             ;R6RS
(import (scheme r5rs))              ;R7RS
(import (scheme char))              ;R7RS

SYNOPSIS

(string-ci=? string1 string2 string3 ...)
(string-ci<? string1 string2 string3 ...)
(string-ci>? string1 string2 string3 ...)
(string-ci<=? string1 string2 string3 ...)
(string-ci>=? string1 string2 string3 ...)

DESCRIPTION

These procedures are similar to string=?, string<?, etc., but operate on the case-folded versions of the strings. Case-folding is done as if by applying string-foldcase(3scm) to the strings.

RETURN VALUES

Returns a single value, a boolean.

EXAMPLES

(string-ci=? "z" "Z")  =>  #t

;; May return #t in R7RS.
(string-ci<? "z" "Z")  =>  #f

;; Can return #f in R7RS, and the characters may not be supported.
(string-ci=? "Straße" "Strasse")  =>  #t

(string-ci=? "Straße" "STRASSE")  =>  #t

(string-ci=? "XAOΣ" "χαoσ")  =>  #t

COMPATIBILITY

The basic idea of these procedures is the same in all RnRS revisions. However, there are some differences.

R5RS and earlier reports only provided two-argument variants.

R6RS implementations are mainly the same, except that they may behave differently depending on which version of the Unicode standard they support.

R7RS implementations may lack support for some characters. The order is also implementation-defined, with lexicographical ordering only being one option.

ERRORS

This procedure can raise exceptions with the following condition types:
&assertion (R6RS)
The wrong number of arguments was passed or an argument was outside its domain.
R7RS
The assertions described above are errors. Implementations may signal an error, extend the procedure's domain of definition to include such arguments, or fail catastrophically.

SEE ALSO

string=?(3scm), string-foldcase(3scm)

STANDARDS

R4RS, IEEE Scheme, R5RS, R6RS, R7RS

HISTORY

These procedures first appeared in R2RS.

AUTHORS

This page is part of the scheme-manpages project. It includes materials from the RnRS documents. More information can be found at https://github.com/schemedoc/manpages/.

Markup created by unroff 1.0sc,    March 04, 2023.