Information technology — Document Schema Definition Language (DSDL) — Part 2: Regular-grammar-based validation — RELAX NG
信息技术——文档模式定义语言(DSDL)第2部分:基于规则语法的验证——放松
ISO/IEC 19757-2:2008 specifies RELAX NG, a schema language for XML. A RELAX NG schema specifies a pattern for the structure and content of an XML document. The pattern is specified by using a regular tree grammar.
It establishes requirements for RELAX NG schemas and specifies when an XML document matches the pattern specified by a RELAX NG schema.