19757-7

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Abstract

ISO/IEC 19757-7:2009 [1] specifies a Character Repertoire Description Language (CREPDL); a CREPDL schema describes a character repertoire. ISO/IEC 19757-7:2009 introduces kernels and hulls of repertoires, then specifies the syntax of CREPDL schemas and the semantics of a correct CREPDL schema; the semantics specify when a character is in a repertoire described by a CREPDL schema. ISO/IEC 19757-7:2009 defines CREPDL processors and their behaviour. Finally, it describes differences of conformant CREPDL processors, and provides examples of CREPDL schemas.

Status and Historical Background

CREPDL has been already published as an ISO/IEC standard (19757-7:2009). See this official page [2].

CREPDL was developed by SC34/WG1. But there is a predecessor in W3C. It is "A Notation for Character Collections for the WWW" (W3C Note) [3].

At present, no schema languages or form specifications use CREPDL. However, there is a plan to allow the use of CREPDL as part of RELAXNGV2.

Schemas for CREPDL

CREPDL schemas are represented as XML documents. They are required to be valida against an NVDL script, which in turn references to a RELAX NG schema.

NVDL

A (normative) NVDL crepdl.nvdl [4] for CREPDL. It references to crepdl.rnc.

RELAX NG

A (normative) RELAX NG schema in the compact syntax crepdl.rnc [5] for CREPDL.

Reference Implementation

An implementation in F# by the project editor is available at https://www.assembla.com/wiki/show/CrepdlValidatorInFsharp.

Tutorial

See CREPDL

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