UCA (Unicode Collation Algorithm) Collation URI Document

21 March 2017

1 Introduction

This document describes the family of URIs having the scheme and path http://www.w3.org/2013/collation/UCA, followed by an optional query part. The URIs in this family are used to identify tailorings of the Unicode Collation Algorithm defined by the Unicode Consortium. The form of these URIs (specifically, the syntax and semantics of the query part of the URI) is defined in the [XPath and XQuery Functions and Operators 3.1] specification (March 2017 version).

The Unicode Collation Algorithm itself is defined in [UTS #10].

The Unicode Collation Algorithm is not to be confused with the Unicode Codepoint Collation.

These URIs identify collations. (They do not identify namespaces. There is thus no associated namespace prefix, and no associated schema.)

For updated information, please refer to the latest version of the [XPath and XQuery Functions and Operators 3.1] specification.

This document contains a directory of links to related resources, using RDDL (as defined in [Resource Directory Description Language (RDDL)]).

It is GRDDL-enabled (as defined in [Gleaning Resource Descriptions from Dialects of Languages (GRDDL)]), that is to say that a GRDDL-compliant processor can extract useful RDF (as defined in [Resource Description Framework (RDF): Concepts and Abstract Syntax]) representations of the information contained herein.

2 Collations

The ASCII-Case-Insensitive collation provides the ability to compare strings for equality without distinguishing lowercase ASCII letters from their corresponding uppercase counterparts. Every implementation of XPath 2.0 and higher, and every implementation of XQuery 1.0 and higher, must support this collation. This collation is intended to provide a mechanism for comparing strings using rules that are compatible with those of HTML5. It defines equality matching of strings only; any use of this collation for sorting strings produces implementation-defined results.

3 Normative References

XPath and XQuery Functions and Operators 3.1
UTS #10
Unicode Technical Standard #10: Unicode Collation Algorithm. Ed. Mark Davis and Ken Whistler, Unicode Consortium. The current version is 9.0.0, dated 2016-05-18. The version to be used is implementation-defined. Available at: http://www.unicode.org/reports/tr10/.

4 Non-Normative References

Resource Directory Description Language (RDDL)
Gleaning Resource Descriptions from Dialects of Languages (GRDDL)
Resource Description Framework (RDF): Concepts and Abstract Syntax