XML规范英文版.docx

1、XML规范英文版REC-xml-19980210Extensible Markup Language (XML) 1.0W3C Recommendation 10-February-1998 This version: http:/www.w3.org/TR/1998/REC-xml-19980210 http:/www.w3.org/TR/1998/REC-xml-19980210.xml http:/www.w3.org/TR/1998/REC-xml-19980210.html http:/www.w3.org/TR/1998/REC-xml-19980210.pdf http:/www

2、.w3.org/TR/1998/REC-xml-19980210.ps Latest version: http:/www.w3.org/TR/REC-xml Previous version: http:/www.w3.org/TR/PR-xml-971208 Editors: Tim Bray (Textuality and Netscape) Jean Paoli (Microsoft) C. M. Sperberg-McQueen (University of Illinois at Chicago) AbstractThe Extensible Markup Language (XM

3、L) is a subset of SGML that is completely described in this document. Its goal is to enable generic SGML to be served, received, and processed on the Web in the way that is now possible with HTML. XML has been designed for ease of implementation and for interoperability with both SGML and HTML.Statu

4、s of this documentThis document has been reviewed by W3C Members and other interested parties and has been endorsed by the Director as a W3C Recommendation. It is a stable document and may be used as reference material or cited as a normative reference from another document. W3Cs role in making the

5、Recommendation is to draw attention to the specification and to promote its widespread deployment. This enhances the functionality and interoperability of the Web.This document specifies a syntax created by subsetting an existing, widely used international text processing standard (Standard Generali

6、zed Markup Language, ISO 8879:1986(E) as amended and corrected) for use on the World Wide Web. It is a product of the W3C XML Activity, details of which can be found at http:/www.w3.org/XML. A list of current W3C Recommendations and other technical documents can be found at http:/www.w3.org/TR. This

7、 specification uses the term URI, which is defined by Berners-Lee et al., a work in progress expected to update IETF RFC1738 and IETF RFC1808. The list of known errors in this specification is available at http:/www.w3.org/XML/xml-19980210-errata.Please report errors in this document to xml-editorw3

8、.org. Extensible Markup Language (XML) 1.0Table of Contents1. Introduction1.1 Origin and Goals1.2 Terminology2. Documents2.1 Well-Formed XML Documents2.2 Characters2.3 Common Syntactic Constructs2.4 Character Data and Markup2.5 Comments2.6 Processing Instructions2.7 CDATA Sections2.8 Prolog and Docu

9、ment Type Declaration2.9 Standalone Document Declaration2.10 White Space Handling2.11 End-of-Line Handling2.12 Language Identification3. Logical Structures3.1 Start-Tags, End-Tags, and Empty-Element Tags3.2 Element Type Declarations3.2.1 Element Content3.2.2 Mixed Content3.3 Attribute-List Declarati

10、ons3.3.1 Attribute Types3.3.2 Attribute Defaults3.3.3 Attribute-Value Normalization3.4 Conditional Sections4. Physical Structures4.1 Character and Entity References4.2 Entity Declarations4.2.1 Internal Entities4.2.2 External Entities4.3 Parsed Entities4.3.1 The Text Declaration4.3.2 Well-Formed Pars

11、ed Entities4.3.3 Character Encoding in Entities4.4 XML Processor Treatment of Entities and References4.4.1 Not Recognized4.4.2 Included4.4.3 Included If Validating4.4.4 Forbidden4.4.5 Included in Literal4.4.6 Notify4.4.7 Bypassed4.4.8 Included as PE4.5 Construction of Internal Entity Replacement Tex

12、t4.6 Predefined Entities4.7 Notation Declarations4.8 Document Entity5. Conformance5.1 Validating and Non-Validating Processors5.2 Using XML Processors6. NotationAppendicesA. ReferencesA.1 Normative ReferencesA.2 Other ReferencesB. Character ClassesC. XML and SGML (Non-Normative)D. Expansion of Entit

13、y and Character References (Non-Normative)E. Deterministic Content Models (Non-Normative)F. Autodetection of Character Encodings (Non-Normative)G. W3C XML Working Group (Non-Normative)1. IntroductionExtensible Markup Language, abbreviated XML, describes a class of data objects called XML documents a

14、nd partially describes the behavior of computer programs which process them. XML is an application profile or restricted form of SGML, the Standard Generalized Markup Language ISO 8879. By construction, XML documents are conforming SGML documents. XML documents are made up of storage units called en

15、tities, which contain either parsed or unparsed data. Parsed data is made up of characters, some of which form character data, and some of which form markup. Markup encodes a description of the documents storage layout and logical structure. XML provides a mechanism to impose constraints on the stor

16、age layout and logical structure.A software module called an XML processor is used to read XML documents and provide access to their content and structure. It is assumed that an XML processor is doing its work on behalf of another module, called the application. This specification describes the requ

17、ired behavior of an XML processor in terms of how it must read XML data and the information it must provide to the application.1.1 Origin and GoalsXML was developed by an XML Working Group (originally known as the SGML Editorial Review Board) formed under the auspices of the World Wide Web Consortiu

18、m (W3C) in 1996. It was chaired by Jon Bosak of Sun Microsystems with the active participation of an XML Special Interest Group (previously known as the SGML Working Group) also organized by the W3C. The membership of the XML Working Group is given in an appendix. Dan Connolly served as the WGs cont

19、act with the W3C. The design goals for XML are: 1. XML shall be straightforwardly usable over the Internet. 2. XML shall support a wide variety of applications. 3. XML shall be compatible with SGML. 4. It shall be easy to write programs which process XML documents. 5. The number of optional features

20、 in XML is to be kept to the absolute minimum, ideally zero. 6. XML documents should be human-legible and reasonably clear. 7. The XML design should be prepared quickly. 8. The design of XML shall be formal and concise. 9. XML documents shall be easy to create. 10. Terseness in XML markup is of mini

21、mal importance.This specification, together with associated standards (Unicode and ISO/IEC 10646 for characters, Internet RFC 1766 for language identification tags, ISO 639 for language name codes, and ISO 3166 for country name codes), provides all the information necessary to understand XML Version

22、 1.0 and construct computer programs to process it.This version of the XML specification may be distributed freely, as long as all text and legal notices remain intact.1.2 TerminologyThe terminology used to describe XML documents is defined in the body of this specification. The terms defined in the

23、 following list are used in building those definitions and in describing the actions of an XML processor: may Conforming documents and XML processors are permitted to but need not behave as described. must Conforming documents and XML processors are required to behave as described; otherwise they ar

24、e in error. error A violation of the rules of this specification; results are undefined. Conforming software may detect and report an error and may recover from it. fatal error An error which a conforming XML processor must detect and report to the application. After encountering a fatal error, the

25、processor may continue processing the data to search for further errors and may report such errors to the application. In order to support correction of errors, the processor may make unprocessed data from the document (with intermingled character data and markup) available to the application. Once

26、a fatal error is detected, however, the processor must not continue normal processing (i.e., it must not continue to pass character data and information about the documents logical structure to the application in the normal way). at user option Conforming software may or must (depending on the modal

27、 verb in the sentence) behave as described; if it does, it must provide users a means to enable or disable the behavior described. validity constraint A rule which applies to all valid XML documents. Violations of validity constraints are errors; they must, at user option, be reported by validating

28、XML processors. well-formedness constraint A rule which applies to all well-formed XML documents. Violations of well-formedness constraints are fatal errors. match (Of strings or names:) Two strings or names being compared must be identical. Characters with multiple possible representations in ISO/I

29、EC 10646 (e.g. characters with both precomposed and base+diacritic forms) match only if they have the same representation in both strings. At user option, processors may normalize such characters to some canonical form. No case folding is performed. (Of strings and rules in the grammar:) A string ma

30、tches a grammatical production if it belongs to the language generated by that production. (Of content and content models:) An element matches its declaration when it conforms in the fashion described in the constraint Element Valid. for compatibility A feature of XML included solely to ensure that

31、XML remains compatible with SGML. for interoperability A non-binding recommendation included to increase the chances that XML documents can be processed by the existing installed base of SGML processors which predate the WebSGML Adaptations Annex to ISO 8879. 2. DocumentsA data object is an XML document if it is well-formed, as defined in this specification. A well-formed XML doc