ISO/IEC 19757-9:2008 信息技术 文档模式定义语言（DSDL） 第9部分：文档型定义（DTDs）中名称空间和数据型声明

标准编号：ISO/IEC 19757-9:2008

中文名称：信息技术 文档模式定义语言（DSDL） 第9部分：文档型定义（DTDs）中名称空间和数据型声明

英文名称：Information technology — Document Schema Definition Languages (DSDL) — Part 9: Namespace and datatype declaration in Document Type Definitions (DTDs)

发布日期：2008-11

标准范围

ISO/IEC 19757-9:20 08定义了一种语言，该语言旨在扩展XML文档类型定义（DTD）的声明性功能，包括声明DTD中的一些或全部元素和属性名称所属的一个或多个名称空间，声明对具有内容模型的元素的内容的约束，以包含其名称属于一个或多个指定名称空间的元素，声明仅包含数据内容的元素和属性值的数据类型。ISO/IEC 19757-9:20 08为此语言定义了两种可选的语法绑定。第一种语法绑定使用XML处理指令，并且被设计成使这种语言的声明能够嵌入到XML DTD中，而不会使DTD无效或就遗留DTD解析器而言改变其解释。该第一语法还提供了将DTD与包含任一语法中的声明的外部声明子集相关联的手段。该语法是使用W3C XML中使用的修改后的BNF语法符号来定义的。第二个定义的语法绑定使用XML文档语法。语法规则由符合ISO/IEC 19757-2中定义的宽松紧凑语法的模式定义。该语法旨在使该语言中的声明几乎完全用XML表示（在这种情况下，需要在DTD中插入一个XML处理指令），以便于使用现有XML工具实现，无论是作为嵌入在XML实例中的命名空间限定片段，还是作为单独的XML文档。

ISO/IEC 19757-9:2008 defines a language that is designed to extend the declarative functionality of an XML Document Type Definition (DTD) to include

• declaring one or more namespaces to which some or all of the element and attribute names in a DTD belong,


• declaring constraints on the content of elements with content model ANY to contain elements whose names belong to one or more specified namespaces,


• declaring datatypes for elements that contain data content only and for attribute values.

ISO/IEC 19757-9:2008 defines two alternative syntax bindings for this language. The first syntax binding uses XML processing instructions and is designed to enable declarations in this language to be embedded within an XML DTD without invalidating the DTD or altering its interpretation so far as legacy DTD parsers are concerned. This first syntax also provides a means of associating a DTD with an external declarations subset containing declarations in either syntax. This syntax is defined using the modified BNF syntax notation used in W3C XML. The second defined syntax binding uses an XML document syntax. The syntax rules are defined by a schema that conforms to the RELAX NG Compact Syntax defined in ISO/IEC 19757-2. This syntax is designed to enable declarations in this language to be expressed almost entirely in XML (in this case one XML processing instruction needs to be inserted in the DTD) to facilitate implementation using existing XML tools, either as a namespace-qualified fragment embedded within an XML instance or as a separate XML document.

标准预览图