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Extensible Markup Language (XML) 1.0 REC-xml-&iso6.doc.date; W3C Recommendation &draft.day;&draft.month;&draft.year; http://www.w3.org/TR/1998/REC-xml-&iso6.doc.date; http://www.w3.org/TR/1998/REC-xml-&iso6.doc.date;.xml http://www.w3.org/TR/1998/REC-xml-&iso6.doc.date;.html http://www.w3.org/TR/1998/REC-xml-&iso6.doc.date;.pdf http://www.w3.org/TR/1998/REC-xml-&iso6.doc.date;.ps httwww.w3.org/TR/REC-xml http://www.w3.org/TR/PR-xml-971208 Tim Bray Textuality and Netscape tbray@textuality.com Jean Paoli Microsoft jeanpa@microsoft.com C. M. Sperberg-McQueen University of Illinois at Chicago cmsmcq@uic.edu

The Extensible Markup Language (XML) 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.

This 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. W3C's role in making the Recommendation is to draw attention to the spPcification 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 Generalized 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 specification uses the term URI, which is defined by , a work in progress expected to update and .

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-editor@w3.org.

Chicago, Vancouver, Mountain View, et al.: World-Wide Web Consortium, XML Working Group, 1996, 1997.

Created in electronic form.

 English Extended Backus-Naur Form (formal grammar) 1997-12-03 : CMSMcQ : yet further changes 1997-12-02 : TB : further changes (see TB to XML WG, 2 December 1997) 1997-12-02 : CMSMcQ : deal with as many corrections and comments from the proofreaders as possible: entify hard-coded document date in pubdate element, change expansion of entity WebSGML, update status description as per Dan Connolly (am not sure about refernece to Berners-Lee et al.), add 'The' to abstract as per WG decision, move Relationship to Existing Standards to back matter and combine with References, re-order back matter so normative appendices come first, re-tag back matter so informative appendices are tagged informdiv1, remove XXX XXX from list of 'normative' specs in prose, move some references from Other References to Normative References, add RFC 1738, 1808, and 2141 to Other References (they are not normative since we do not require the processor to enforce any rules based on them), add reference to 'Fielding draft' (Berners-Lee et al.), move notation section to end of body, drop URIchar non-terminal and use SkipLit instead, lose stray reference to defunct nonterminal 'markupdecls', move reference to Aho et al. into appendix (Tim's right), add prose note saying that hash marks and fragment identifiers are NOT part of the URI formally speaking, and are NOT legal in system identifiers (processor 'may' signal an error). Work through: Tim Bray reacting to James Clark, Tim Bray on his own, Eve Maler, NOT DONE YET: change binary / text to unparsed / parsed. handle James's suggestion about < in attriubte values uppercase hex characters, namechar list, 1997-12-01 : JB : add some column-width parameters 1997-12-01 : CMSMcQ : begin round of changes to incorporate recent WG decisions and other corrections: binding sources of character encoding info (27 Aug / 3 Sept), correct wording of Faust quotation (restore dropped line), drop SDD from EncodingDecl, change text at version number 1.0, drop misleading (wrong!) sentence about ignorables and extenders, modify definxamples with Byte Order Mark. Add content model as a term and clarify that it applies to both mixed and element content. 1997-06-30 : CMSMcQ : change date, some cosmetic changes, changes to productions for choice, seq, Mixed, NotationType, Enumeration. Follow James Clark's suggestion and prohibit conditional sections in internal subset. TO DO: simplify production for ignored sections as a result, since we don't need to worry about parsers whi 1997-06-29 : TB : various edits 1997-06-29 : CMSMcQ : further changes: Suppress old FINAL EDIT comments and some dead material. Revise occurrences of % in grammar to exploit Henry Thompson's pun, especially markupdecl and attdef. Remove RMD requirement relating to element content (?). 1997-06-28 : CMSMcQ : Various changes for 1 July draft: Add text for draconian error handling (introduce the term Fatal Error). RE deleta est (changing wording from original announcement to restrict the requirement to validating parsers). Tag definition of validawwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwww it meant 'may or may not'. 1997-03-21 : TB : massive changes on plane flight from Chicago to Vancouver 1997-03-21 : CMSMcQ : correct as many reported errors as possible. 1997-03-20 : CMSMcQ : correct typos listed in CMSMcQ hand copy of spec. 1997 James Clark: Define the set of characters from which [^abc] subtracts. Charref should use just [0-9] not Digit. Location info needs cleaner treatment: remove? (ERB question). One example of a PI has wrong pic. Clarify discussion of encoding names. Encoding failure should lead to unspecified results; don't prescribe error recovery. Don't require exposure of entity boundaries. Ignore white space in element content. Reserve entity names of the form u-NNNN. Clarify relative URLs. And some of my own: Correct productions for content model: model cannot consist of a name, so "elements ::= cp" is no good. 1996-11-11 : CMSMcQ : revise for style. Add new rhs to entity declaration, for parameter entities. 1996-11-10 : CMSMcQ : revise for style. Fix / complete section on names, characters. Add sections on parameter entities, conditional sections. Still to do: Add compatibility note on deterministic content models. Finish stylistic revision. 1996-10-31 : TB : Add Entity Handling section 1996-10-30 : TB : Clean up term & termdef. Slip in ERB decision re EMPTY. 1996-10-28 : TB : Change DTD. Implement some of Michael's suggestions. Change comments back to //. Introduce language for XML namespace reservation. Add section on white-space handling. Lots more cleanup. 1996-10-24 : CMSMcQ : quick tweaks, implement some ERB decisions. Characters are not integers. Comments are /* */ not //. Add bibliographic refs to 10646, HyTime, Unicode. Rename old Cdata as MsData since it's only seen in marked sections. Call them attribute-value pairs not name-value pairs, except once. Internal subset is optional, needs '?'. Implied attributes should be signaled to the app, not have values supplied by processor. 1996-10-16 : TB : track down & excise all DSD references; introduce some EBNF for entity declarations. 1996-10-?? nsistency check, fix up scraps so they all parse, get formatter working, correct a few productions. 1996-10-10/11 : CMSMcQ : various maintenance, stylistic, and organizational changes: Replace a few literals with xmlpio and pi""entities, to make them consistent and ensure we can change pic reliably when the ERB votes. Drop paragraph on recognizers from notation section. Add match, exact match to terminology. Move old 2.2 XML Processors and Apps into intro. Mention comments, PIs, and marked sections in discussion of delimiter escaping. Streamline discussion of doctype decl syntax. Drop old section of 'PI syntax' for doctype decl, and add section on partial-DTD summary PIs to end of Logical Structures section. Revise DSD syntax section to use Tim's subset-in-a-PI mechanism. 1996-10-10 : TB : eliminate name recognizers (and more?) 1996-10-09 : CMSMcQ : revise for style, consistency through 2.3 (Characters) 1996-10-09 : CMSMcQ : re-unite everything for convenience, at least temporarily, and revise quickly 1996-10-08 : TB : first major homogenization pass 1996-10-08 : TB : turn "current" attribute on div type into CDATA 1996-10-02 : TB : remould into skeleton + entities 1996-09-30 : CMSMcQ : add a few more sections prior to exchange with Tim. 1996-09-20 : CMSMcQ : finish transcribing notes. 1996-09-19 : CMSMcQ : begin transcribing notes for draft. 1996-09-13 : CMSMcQ : made outline from notes of 09-06, do some housekeeping
is used to read XML documents and provide access to their content and structure. It is @ssumed that an XML processor is doing its work on behalf of another module, called the application. This specification describes the required beh\vior of an XML processor in terms of how it must read XML data and the information it must provide to the application.

Origin and Goals

XML was developed by an XML Working Group (orisable over the Internet.

XML shall support a wide variey of applications.

XML shall be compatible with SGML.

It shall be easy to write programs which process XML documents.

The number of optional features in XML is to be kept to the absolute minimum, ideally zero.

XML documents shou