draft-ietf-atompub-format-05.txt		draft-ietf-atompub-format-06.txt
	Network Working Group M. Nottingham, Ed.		Network Working Group M. Nottingham, Ed.
	Internet-Draft		Internet-Draft
	Expires: July 27, 2005 R. Sayre, Ed.		Expires: September 13, 2005 R. Sayre, Ed.
	Boswijck Memex Consulting		Boswijck Memex Consulting
	January 26, 2005		March 12, 2005
	The Atom Syndication Format		The Atom Syndication Format
	draft-ietf-atompub-format-05		draft-ietf-atompub-format-06
	Status of this Memo		Status of this Memo
	By submitting this Internet-Draft, I certify that any applicable		This document is an Internet-Draft and is subject to all provisions
	patent or other IPR claims of which I am aware have been disclosed,		of Section 3 of RFC 3667. By submitting this Internet-Draft, each
	and any of which I become aware will be disclosed, in accordance with		author represents that any applicable patent or other IPR claims of
			which he or she is aware have been or will be disclosed, and any of
			which he or she become aware will be disclosed, in accordance with
	RFC 3668.		RFC 3668.
	Internet-Drafts are working documents of the Internet Engineering		Internet-Drafts are working documents of the Internet Engineering
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	Internet-Drafts.		Internet-Drafts.
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	material or to cite them other than as "work in progress."		material or to cite them other than as "work in progress."
	The list of current Internet-Drafts can be accessed at		The list of current Internet-Drafts can be accessed at
	http://www.ietf.org/ietf/1id-abstracts.txt.		http://www.ietf.org/ietf/1id-abstracts.txt.
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	This Internet-Draft will expire on July 27, 2005.		This Internet-Draft will expire on September 13, 2005.
	Copyright Notice		Copyright Notice
	Copyright (C) The Internet Society (2005). All Rights Reserved.		Copyright (C) The Internet Society (2005).
	Abstract		Abstract
	This document specifies Atom, an XML-based Web content and metadata		This document specifies Atom, an XML-based Web content and metadata
	syndication format.		syndication format.
	Table of Contents		Table of Contents
	1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 4		1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 4
	1.1 Editorial Notes . . . . . . . . . . . . . . . . . . . . . 4		1.1 Editorial Notes . . . . . . . . . . . . . . . . . . . . . 4
	1.2 Example . . . . . . . . . . . . . . . . . . . . . . . . . 5		1.2 Example . . . . . . . . . . . . . . . . . . . . . . . . . 5
	1.3 Conformance . . . . . . . . . . . . . . . . . . . . . . . 5		1.3 Notational Conventions . . . . . . . . . . . . . . . . . . 5
	1.4 Notational Conventions . . . . . . . . . . . . . . . . . . 5
	2. Atom Documents . . . . . . . . . . . . . . . . . . . . . . . 7		2. Atom Documents . . . . . . . . . . . . . . . . . . . . . . . 7
	3. Common Atom Constructs . . . . . . . . . . . . . . . . . . . 9		3. Common Atom Constructs . . . . . . . . . . . . . . . . . . . 9
	3.1 Text Constructs . . . . . . . . . . . . . . . . . . . . . 9		3.1 Text Constructs . . . . . . . . . . . . . . . . . . . . . 9
	3.1.1 "type" Attribute . . . . . . . . . . . . . . . . . . . 9		3.1.1 "type" Attribute . . . . . . . . . . . . . . . . . . . 9
	3.2 Person Constructs . . . . . . . . . . . . . . . . . . . . 10		3.2 Person Constructs . . . . . . . . . . . . . . . . . . . . 11
	3.2.1 The "atom:name" Element . . . . . . . . . . . . . . . 10		3.2.1 The "atom:name" Element . . . . . . . . . . . . . . . 11
	3.2.2 The "atom:uri" Element . . . . . . . . . . . . . . . . 10		3.2.2 The "atom:uri" Element . . . . . . . . . . . . . . . . 11
	3.2.3 The "atom:email" Element . . . . . . . . . . . . . . . 11		3.2.3 The "atom:email" Element . . . . . . . . . . . . . . . 11
	3.3 Date Constructs . . . . . . . . . . . . . . . . . . . . . 11		3.3 Date Constructs . . . . . . . . . . . . . . . . . . . . . 11
	3.4 Service Constructs . . . . . . . . . . . . . . . . . . . . 11		4. Atom Element Definitions . . . . . . . . . . . . . . . . . . 13
	3.4.1 The "href" Attribute . . . . . . . . . . . . . . . . . 11		4.1 Container Elements . . . . . . . . . . . . . . . . . . . . 13
	3.5 Identity Constructs . . . . . . . . . . . . . . . . . . . 11		4.1.1 The "atom:feed" Element . . . . . . . . . . . . . . . 13
	3.5.1 Dereferencing Identity Constructs . . . . . . . . . . 12		4.1.2 The "atom:entry" Element . . . . . . . . . . . . . . . 14
	3.5.2 Comparing Identity Constructs . . . . . . . . . . . . 12		4.1.3 The "atom:content" Element . . . . . . . . . . . . . . 16
	4. Element Definitions . . . . . . . . . . . . . . . . . . . . 14		4.2 Metadata Elements . . . . . . . . . . . . . . . . . . . . 19
	4.1 The "atom:feed" Element . . . . . . . . . . . . . . . . . 14		4.2.1 The "atom:author" Element . . . . . . . . . . . . . . 19
	4.1.1 The "version" Attribute . . . . . . . . . . . . . . . 14		4.2.2 The "atom:category" Element . . . . . . . . . . . . . 20
	4.2 The "atom:head" Element . . . . . . . . . . . . . . . . . 14		4.2.3 The "atom:contributor" Element . . . . . . . . . . . . 20
	4.2.1 Usage of "atom:head" within "atom:entry" . . . . . . . 16		4.2.4 The "atom:copyright Element . . . . . . . . . . . . . 20
	4.3 The "atom:entry" Element . . . . . . . . . . . . . . . . . 16		4.2.5 The "atom:generator" Element . . . . . . . . . . . . . 21
	4.4 The "atom:title" Element . . . . . . . . . . . . . . . . . 18		4.2.6 The "atom:icon" Element . . . . . . . . . . . . . . . 21
	4.5 The "atom:id" Element . . . . . . . . . . . . . . . . . . 18		4.2.7 The "atom:id" Element . . . . . . . . . . . . . . . . 21
	4.6 The "atom:link" Element . . . . . . . . . . . . . . . . . 18		4.2.8 The "atom:image" Element . . . . . . . . . . . . . . . 23
	4.6.1 The "href" Attribute . . . . . . . . . . . . . . . . . 19		4.2.9 The "atom:link" Element . . . . . . . . . . . . . . . 23
	4.6.2 The "rel" Attribute . . . . . . . . . . . . . . . . . 19		4.2.10 The "atom:published" Element . . . . . . . . . . . . 26
	4.6.3 The "type" Attribute . . . . . . . . . . . . . . . . . 20		4.2.11 The "atom:source-feed" Element . . . . . . . . . . . 26
	4.6.4 The "hreflang" Attribute . . . . . . . . . . . . . . . 20		4.2.12 The "atom:subtitle" Element . . . . . . . . . . . . 26
	4.6.5 The "title" Attribute . . . . . . . . . . . . . . . . 20		4.2.13 The "atom:summary" Element . . . . . . . . . . . . . 27
	4.6.6 The "length" Attribute . . . . . . . . . . . . . . . . 20		4.2.14 The "atom:title" Element . . . . . . . . . . . . . . 27
	4.7 The "atom:updated" Element . . . . . . . . . . . . . . . . 20		4.2.15 The "atom:updated" Element . . . . . . . . . . . . . 27
	4.8 The "atom:published" Element . . . . . . . . . . . . . . . 21		5. Securing Atom Documents . . . . . . . . . . . . . . . . . . 28
	4.9 The "atom:author" Element . . . . . . . . . . . . . . . . 21		5.1 Digital Signatures . . . . . . . . . . . . . . . . . . . . 28
	4.10 The "atom:contributor" Element . . . . . . . . . . . . . 21		5.2 Encryption . . . . . . . . . . . . . . . . . . . . . . . . 28
	4.11 The "atom:host" Element . . . . . . . . . . . . . . . . 21		6. Extending Atom . . . . . . . . . . . . . . . . . . . . . . . 29
	4.12 The "atom:copyright" Element . . . . . . . . . . . . . . 21		6.1 Extensions From Non-Atom Vocabularies . . . . . . . . . . 29
	4.13 The "atom:category" Element . . . . . . . . . . . . . . 22		6.2 Extensions To the Atom Vocabulary . . . . . . . . . . . . 29
	4.13.1 The "term" Attribute . . . . . . . . . . . . . . . . 22		6.3 Software Processing of Foreign Markup . . . . . . . . . . 29
	4.13.2 The "scheme" Attribute . . . . . . . . . . . . . . . 22		6.4 Extension Elements . . . . . . . . . . . . . . . . . . . . 29
	4.13.3 The "label" attribute . . . . . . . . . . . . . . . 22		6.4.1 Simple Extension Elements . . . . . . . . . . . . . . 30
	4.14 The "atom:summary" Element . . . . . . . . . . . . . . . 22		6.4.2 Structured Extension Elements . . . . . . . . . . . . 30
	4.15 The "atom:content" Element . . . . . . . . . . . . . . . 23		7. IANA Considerations . . . . . . . . . . . . . . . . . . . . 31
	4.15.1 The "type" attribute . . . . . . . . . . . . . . . . 23		7.1 Registry of Link Relations . . . . . . . . . . . . . . . . 31
	4.15.2 The "src" attribute . . . . . . . . . . . . . . . . 23		8. Security Considerations . . . . . . . . . . . . . . . . . . 33
	4.15.3 Processing Model . . . . . . . . . . . . . . . . . . 24		8.1 HTML and XHTML Content . . . . . . . . . . . . . . . . . . 33
	4.16 The "atom:introspection" Element . . . . . . . . . . . . 25		8.2 URIs . . . . . . . . . . . . . . . . . . . . . . . . . . . 33
	4.17 The "atom:post" Element . . . . . . . . . . . . . . . . 25		8.3 IRIs . . . . . . . . . . . . . . . . . . . . . . . . . . . 33
	4.18 The "atom:edit" Element . . . . . . . . . . . . . . . . 25		8.4 Encryption and Signing . . . . . . . . . . . . . . . . . . 33
	4.19 The "atom:tagline" Element . . . . . . . . . . . . . . . 25		9. References . . . . . . . . . . . . . . . . . . . . . . . . . 34
	4.20 The "atom:generator" Element . . . . . . . . . . . . . . 25		9.1 Normative References . . . . . . . . . . . . . . . . . . . 34
	4.21 The "atom:info" Element . . . . . . . . . . . . . . . . 26		9.2 Informative References . . . . . . . . . . . . . . . . . . 35
	5. Managing Feed State . . . . . . . . . . . . . . . . . . . . 27
	6. Securing Atom Documents . . . . . . . . . . . . . . . . . . 28
	6.1 Digital Signatures . . . . . . . . . . . . . . . . . . . . 28
	6.2 Encryption . . . . . . . . . . . . . . . . . . . . . . . . 28
	7. Embedding Atom in Other Formats . . . . . . . . . . . . . . 29
	8. Extending Atom . . . . . . . . . . . . . . . . . . . . . . . 30
	9. IANA Considerations . . . . . . . . . . . . . . . . . . . . 31
	9.1 Registry of Link Relations . . . . . . . . . . . . . . . . 31
	10. Security Considerations . . . . . . . . . . . . . . . . . . 33
	11. References . . . . . . . . . . . . . . . . . . . . . . . . . 34
	11.1 Normative References . . . . . . . . . . . . . . . . . . . 34
	11.2 Informative References . . . . . . . . . . . . . . . . . . 35
	Authors' Addresses . . . . . . . . . . . . . . . . . . . . . 36		Authors' Addresses . . . . . . . . . . . . . . . . . . . . . 36
	A. Contributors . . . . . . . . . . . . . . . . . . . . . . . . 37		A. Contributors . . . . . . . . . . . . . . . . . . . . . . . . 37
	B. Collected RELAX NG Compact Schema . . . . . . . . . . . . . 38		B. Collected RELAX NG Compact Schema . . . . . . . . . . . . . 38
	C. Revision History . . . . . . . . . . . . . . . . . . . . . . 45		C. Change Log . . . . . . . . . . . . . . . . . . . . . . . . . 45
	Intellectual Property and Copyright Statements . . . . . . . 47		Intellectual Property and Copyright Statements . . . . . . . 48
	1. Introduction		1. Introduction
	Atom is an XML-based document format which describes lists of related		Atom is an XML-based document format that describes lists of related
	information known as "feeds". Feeds are composed of a number of		information known as "feeds". Feeds are composed of a number of
	items, known as "entries", each with an extensible set of attached		items, known as "entries", each with an extensible set of attached
	metadata. For example, each entry has a title.		metadata. For example, each entry has a title.
	The primary use case that Atom addresses is the syndication of Web		The primary use case that Atom addresses is the syndication of Web
	content such as Weblogs and news headlines to Web sites as well as		content such as Weblogs and news headlines to Web sites as well as
	directly to user agents. However, nothing precludes it from being		directly to user agents. However, nothing precludes it from being
	used for other purposes and kinds of content.		used for other purposes and kinds of content.
	Details of communication protocols between software agents using Atom
	can be found in the Atom Protocol specification [Atom-protocol].
	[[ more motivation / design principles ]]
	1.1 Editorial Notes		1.1 Editorial Notes
	The Atom format is a work-in-progress, and this draft is both		The Atom format is a work-in-progress, and this draft is both
	incomplete and likely to change rapidly. As a result, THE FORMAT		incomplete and likely to change rapidly. As a result, THE FORMAT
	DESCRIBED BY THIS DRAFT SHOULD NOT BE DEPLOYED, either in production		DESCRIBED BY THIS DRAFT SHOULD NOT BE DEPLOYED, either in production
	systems or in any non-experimental fashion on the Internet.		systems or in any non-experimental fashion on the Internet.
	Discussion of this draft happens in two fora;		Discussion of this draft happens in two fora;
	The mailing list [1]		The mailing list <http://www.imc.org/atom-syntax/index.html>
	The Atom Wiki Web site [2]		The Atom Wiki Web site
			<http://www.intertwingly.net/wiki/pie/FrontPage>
	Active development takes place on the mailing list, while the Wiki is		Active development takes place on the mailing list, while the Wiki is
	used for issue tracking and new proposals.		used for issue tracking and new proposals.
	This document is an early draft and known to be incomplete. Topics
	marked [[like this]] indicate where additional text is likely to be
	added.
	1.2 Example		1.2 Example
	A minimal, single-entry Atom Feed Document:		A minimal, single-entry Atom Feed Document:
	<?xml version="1.0" encoding="UTF-8"?>		<?xml version="1.0" encoding="UTF-8"?>
	<feed version="draft-ietf-atompub-format-05:do not deploy"		<feed
	xmlns="http://purl.org/atom/ns#draft-ietf-atompub-format-05">		xmlns="http://purl.org/atom/ns#draft-ietf-atompub-format-06">
	<head>
	<title>Example Feed</title>		<title>Example Feed</title>
	<link href="http://example.org/"/>		<link href="http://example.org/"/>
	<updated>2003-12-13T18:30:02Z</updated>		<updated>2003-12-13T18:30:02Z</updated>
	<author>		<author>
	<name>John Doe</name>		<name>John Doe</name>
	</author>		</author>
	</head>
	<entry>		<entry>
	<title>Atom-Powered Robots Run Amok</title>		<title>Atom-Powered Robots Run Amok</title>
	<link href="http://example.org/2003/12/13/atom03"/>		<link href="http://example.org/2003/12/13/atom03"/>
	<id>vemmi://example.org/2003/32397</id>		<id>urn:uuid:1225c695-cfb8-4ebb-aaaa-80da344efa6a</id>
	<updated>2003-12-13T18:30:02Z</updated>		<updated>2003-12-13T18:30:02Z</updated>
	</entry>		</entry>
	</feed>		</feed>
	1.3 Conformance		[[anchor4: Ask yourself: is the example atom:entry valid?]]
	[[ talk about atom documents and atom consumers, and how requirements		1.3 Notational Conventions
	are placed on them ]]
	1.4 Notational Conventions		This specification describes conformance in terms of two kinds of
			artefacts; Atom Feed Documents and Atom Entry documents.
			Additionally, it places some requirements on Atom Processors.
	The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",		The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
	"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this		"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
	document are to be interpreted as described in BCP 14, [RFC2119].		document are to be interpreted as described in BCP 14, [RFC2119], as
			scoped to those conformance targets.
	This specification uses XML Namespaces [W3C.REC-xml-names-19990114]		This specification uses XML Namespaces [W3C.REC-xml-names-19990114]
	to uniquely identify XML elements and attribute names. It uses the		to uniquely identify XML elements names. It uses the following
	following namespace prefixes for the indicated namespace URIs;		namespace prefixes for the indicated namespace URIs;
	"atom": http://purl.org/atom/ns#draft-ietf-atompub-format-05		"atom": http://purl.org/atom/ns#draft-ietf-atompub-format-06
	Note that the choice of any namespace prefix is arbitrary and not		Note that the choice of any namespace prefix is arbitrary and not
	semantically significant.		semantically significant.
	Atom is specified using terms from the XML Infoset		Atom is specified using terms from the XML Infoset
	[W3C.REC-xml-infoset-20011024]. However, this specification uses a		[W3C.REC-xml-infoset-20040204]. However, this specification uses a
	shorthand for two common terms; the phrase "Information Item" is		shorthand for two common terms; the phrase "Information Item" is
	omitted when naming Element Information Items and Attribute		omitted when naming Element Information Items and Attribute
	Information Items.		Information Items.
	Therefore, when this specification uses the term "element," it is		Therefore, when this specification uses the term "element," it is
	referring to an Element Information Item in Infoset terms. Likewise,		referring to an Element Information Item in Infoset terms. Likewise,
	when it uses the term "attribute," it is referring to an Attribute		when it uses the term "attribute," it is referring to an Attribute
	Information Item.		Information Item.
	Some sections of this specification are illustrated with fragments of		Some sections of this specification are illustrated with fragments of
	skipping to change at page 7, line 12		skipping to change at page 7, line 12
	text of this specification provides the definition of conformance. A		text of this specification provides the definition of conformance. A
	collected schema appears in an informative appendix.		collected schema appears in an informative appendix.
	2. Atom Documents		2. Atom Documents
	This specification describes two kinds of Atom Documents; Atom Feed		This specification describes two kinds of Atom Documents; Atom Feed
	Documents and Atom Entry Documents.		Documents and Atom Entry Documents.
	An Atom Feed Document is a representation of an Atom feed, including		An Atom Feed Document is a representation of an Atom feed, including
	metadata about the feed, and some or all of the entries associated		metadata about the feed, and some or all of the entries associated
	with it. Its document element is atom:feed.		with it. Its root is the atom:feed element.
	An Atom Entry Document represents exactly one Atom Entry, outside of		An Atom Entry Document represents exactly one Atom Entry, outside of
	the context of an Atom Feed. Its document element is atom:entry.		the context of an Atom Feed. Its root is the atom:entry element.
	namespace atom =		namespace
	"http://purl.org/atom/ns#draft-ietf-atompub-format-05"		atom ="http://purl.org/atom/ns#draft-ietf-atompub-format-06"
	start = atomFeed | atomEntry		start = atomFeed | atomEntry
	Both kinds of Atom documents are specified in terms of the XML		Both kinds of Atom documents are specified in terms of the XML
	Information Set, serialised as XML 1.0 [W3C.REC-xml-20040204] and		Information Set, serialised as XML 1.0 [W3C.REC-xml-20040204] and
	identified with the "application/atom+xml" media type. Atom		identified with the "application/atom+xml" media type. Atom
	Documents MUST be well-formed XML.		Documents MUST be well-formed XML.
	Atom constrains the appearance and content of elements and		Atom constrains the appearance and content of elements and
	attributes; unless otherwise stated, Atom Documents MAY contain other		attributes; unless otherwise stated, Atom Documents MAY contain other
	Information Items as appropriate. In particular, Comment Information		Information Items as appropriate. In particular, Comment Information
	Items and Processing Instruction Information Items SHOULD be ignored		Items and Processing Instruction Information Items SHOULD be ignored
	in the normal processing of an Atom Document.		in the normal processing of an Atom Document.
	Any element in an Atom Document MAY have an xml:base attribute. XML		Any element in an Atom Document MAY have an xml:base attribute. XML
	Base [W3C.REC-xmlbase-20010627] processing MUST be applied to any		Base [W3C.REC-xmlbase-20010627] processing MUST be applied to any
	relative reference [RFC3986] present in an Atom Document. This		relative reference [RFC3987] present in an Atom Document. This
	includes such elements and attributes as specified by Atom itself, as		includes such elements and attributes as specified by Atom itself, as
	well as those specified by extensions to Atom.		well as those specified by extensions to Atom.
	Any element in an Atom Document MAY have an xml:lang attribute, whose		Any element in an Atom Document MAY have an xml:lang attribute, whose
	content indicates the natural language of the element's content.		content indicates the natural language for the element and its
			children. The language context is only significant for elements and
			attributes declared to be "language-sensitive" by this specification.
	Requirements regarding the content and interpretation of xml:lang are		Requirements regarding the content and interpretation of xml:lang are
	specified in XML 1.0 [W3C.REC-xml-20040204] Section 2.12.		specified in XML 1.0 [W3C.REC-xml-20040204], Section 2.12.
	atomCommonAttributes =		atomCommonAttributes =
	attribute xml:base { atomUri }?,		attribute xml:base { atomUri }?,
	attribute xml:lang { atomLanguageTag }?		attribute xml:lang { atomLanguageTag }?
	[[ discussion of URI escaping and i18n, IRI ]]		Atom allows the use of IRIs [RFC3987], rather than only URIs
			[RFC3986]. For resolution, IRIs can easily be converted to URIs.
			When comparing IRIs serving as Identity Constructs, they MUST NOT be
			converted to URIs. Please note that by definition, every URI is an
			IRI, so any URI can be used where an IRI is needed.
	[[ discussion of white space ]]		[[anchor7: discussion of white space]]
	Atom is extensible. See the section titled 'Extending Atom' later in		Atom is an extensible format. See the section titled 'Extending
	this document for a full description of how Atom Documents can be		Atom' later in this document for a full description of how Atom
	extended.		Documents can be extended.
			Atom Processors MAY keep state (e.g., metadata in atom:feed, entries)
			sourced from Atom Feed Documents and combine them with other Atom
			Feed Documents, in order to facilitate a contiguous view of the
			contents of a feed. The manner in which Atom Feed Documents are
			combined in order to reconstruct a feed (e.g., updating entries and
			metadata, dealing with missing entries) is out of the scope of this
			specification, but may be defined by an extension to Atom.
	3. Common Atom Constructs		3. Common Atom Constructs
	Many of Atom's elements share a few common structures. This section		Many of Atom's elements share a few common structures. This section
	defines a few such structures and their requirements for convenient		defines a few such structures and their requirements for convenient
	reference by the appropriate element definitions.		reference by the appropriate element definitions.
	When an element is identified as being a particular kind of		When an element is identified as being a particular kind of
	construct, it inherits the corresponding requirements from that		construct, it inherits the corresponding requirements from that
	construct's definition in this section.		construct's definition in this section.
	3.1 Text Constructs		3.1 Text Constructs
	A Text construct contains human readable text, usually in fairly		A Text construct contains human readable text, usually in small
	small quantities.		quantities. Except for the "type" attribute, the content of Text
			constructs is language-sensitive.
	atomPlainTextConstruct =		atomPlainTextConstruct =
	atomCommonAttributes,		atomCommonAttributes,
	attribute type { "TEXT" | "HTML" }?,		attribute type { "text" | "html" }?,
	text		text
	atomXHTMLTextConstruct =		atomXHTMLTextConstruct =
	atomCommonAttributes,		atomCommonAttributes,
	attribute type { "XHTML" },		attribute type { "xhtml" },
	(text|anyElement)*		(text|anyElement)*
	atomTextConstruct = atomPlainTextConstruct | atomXHTMLTextConstruct		atomTextConstruct = atomPlainTextConstruct | atomXHTMLTextConstruct
	3.1.1 "type" Attribute		3.1.1 "type" Attribute
	Text constructs MAY have a "type" attribute. When present, the value		Text constructs MAY have a "type" attribute. [[anchor11: Some feel
	MUST be one of "TEXT", "HTML" or "XHTML". If the "type" attribute is		type attributes with different allowable values in different elements
	not provided, software MUST behave as though it were present with a		is confusing.]]. When present, the value MUST be one of "text",
	value of "TEXT".		"html" or "xhtml". If the "type" attribute is not provided, Atom
			Processors MUST behave as though it were present with a value of
			"text".
	Note that MIME media types [RFC2045] are not acceptable values for		Note that MIME media types [RFC2045] are not acceptable values for
	the "type" attribute.		the "type" attribute.
	If the value is "TEXT", the content of the Text construct MUST NOT		If the value is "text", the content of the Text construct MUST NOT
	contain child elements. Such text is intended to be presented to		contain child elements. Such text is intended to be presented to
	humans in a readable fashion. Thus, software MAY display it using		humans in a readable fashion. Thus, Atom Processors MAY display it
	normal text rendering techniques such as proportional fonts,		using normal text rendering techniques such as proportional fonts,
	white-space collapsing, and justification.		white-space collapsing, and justification.
	If the value of "type" is "HTML", the content of the Text construct		If the value of "type" is "html", the content of the Text construct
	MUST NOT contain child elements, and SHOULD be suitable for handling		MUST NOT contain child elements, and SHOULD be suitable for handling
	by software that knows HTML. The HTML markup must be escaped; for		as HTML [W3C.REC-html401-19991224]. Any markup within MUST be
	example, "<br>" as "&lt;br>". The HTML markup SHOULD be such that it		escaped; for example, "<br>" as "&lt;br>". HTML markup within SHOULD
	could validly appear directly within an HTML <DIV> element.		be such that it could validly appear directly within an HTML <DIV>
	Receiving software which displays the content MAY use the markup to		element, after unescaping. Atom Processors that display such content
	aid in displaying it.		MAY use markup to aid in its display.
	[[example atom entry w/ escaped markup]]		[[anchor12: example atom entry w/ escaped markup]]
	If the value of "type" is "XHTML", the content of the Text construct		If the value of "type" is "xhtml", the content of the Text construct
	MAY contain child elements. The content SHOULD be XHTML text and		MUST be a single XHTML div element [W3C.REC-xhtml-basic-20001219].
	markup that could validly appear directly within an xhtml:div		The XHTML div MUST contain XHTML text and markup that could validly
	element. Receiving software which displays the content MAY use the		appear within an XHTML div element. The XHTML div element itself
	markup to aid in displaying it. Escaped markup is interpreted as a		MUST NOT be considered part of the content. Atom Processors which
	text representation of markup, and MUST NOT be interpreted as markup		display the content MAY use the markup to aid in displaying it.
	itself.		Escaped markup is interpreted as a text representation of markup, and
			MUST NOT be interpreted as markup itself.
			Example:
			...
			<summary type="xhtml">
			<div xmlns="http://www.w3.org/1999/xhtml">
			This is <b>XHTML</b> content.
			</div>
			</summary>
			...
			<summary type="xhtml">
			<xhtml:div xmlns:xhtml="http://www.w3.org/1999/xhtml">
			This is <xhtml:b>XHTML</xhtml:b> content.
			</xhtml:div>
			</summary>
			...
			The following example assumes that the XHTML namespace has been bound
			to the "xh" prefix earlier in the document:
			...
			<summary type="xhtml">
			<xh:div>
			This is <xh:b>XHTML</xh:b> content.
			</xh:div>
			</summary>
			...
	3.2 Person Constructs		3.2 Person Constructs
	A Person construct is an element that describes a person,		A Person construct is an element that describes a person,
	corporation, or similar entity.		corporation, or similar entity (hereafter, 'person').
	Person constructs MAY be extended by namespace-qualified element		Person constructs MAY be extended by namespace-qualified element
	children.		children.
	This specification assigns no significance to the order of appearance		This specification assigns no significance to the order of appearance
	of the child elements in a Person construct.		of the child elements in a Person construct.
	atomPersonConstruct =		atomPersonConstruct =
	atomCommonAttributes,		atomCommonAttributes,
	(element atom:name { text }		(element atom:name { text } &
	& element atom:uri { atomUri }?		element atom:uri { atomUri }? &
	& element atom:email { atomEmailAddress }?)		element atom:email { atomEmailAddress }?)
	3.2.1 The "atom:name" Element		3.2.1 The "atom:name" Element
	The "atom:name" element's content conveys a human-readable name for		The "atom:name" element's content conveys a human-readable name for
	the person. Person constructs MUST contain exactly one "atom:name"		the person. The content of atom:name is language sensitive. Person
	element.		constructs MUST contain exactly one "atom:name" element.
	3.2.2 The "atom:uri" Element		3.2.2 The "atom:uri" Element
	The "atom:uri" element's content conveys a URI associated with the		The "atom:uri" element's content conveys an IRI associated with the
	person. Person constructs MAY contain an atom:uri element, but MUST		person. Person constructs MAY contain an atom:uri element, but MUST
	NOT contain more than one. The content of atom:uri in a Person		NOT contain more than one. The content of atom:uri in a Person
	construct MUST be a URI reference [RFC3986].		construct MUST be an IRI reference [RFC3987].
	xml:base [W3C.REC-xmlbase-20010627] processing MUST be applied to the		xml:base [W3C.REC-xmlbase-20010627] processing MUST be applied to the
	atom:uri element's content.		atom:uri element's content.
	3.2.3 The "atom:email" Element		3.2.3 The "atom:email" Element
	The "atom:email" element's content conveys an e-mail address		The "atom:email" element's content conveys an e-mail address
	associated with the persons. Person constructs MAY contain an		associated with the person. Person constructs MAY contain an
	atom:email element, but MUST NOT contain more than one. Its content		atom:email element, but MUST NOT contain more than one. Its content
	MUST be an e-mail address [RFC2822].		MUST conform to the addr-spec BNF rule in [RFC2822].
	3.3 Date Constructs		3.3 Date Constructs
	A Date construct is an element whose content MUST conform to the		A Date construct is an element whose content MUST conform to the
	date-time BNF rule in [RFC3339].		date-time BNF rule in [RFC3339]. I.e., the content of this element
			matches this regular expression:
	atomDateConstruct =
	atomCommonAttributes,
	xsd:dateTime
	3.4 Service Constructs
	A Service construct is an empty element that conveys the URI of an
	Atom Publishing Protocol [Atom-protocol] service associated with an
	entry or feed.
	atomServiceConstruct =
	atomCommonAttributes,
	attribute href { atomUri }
	3.4.1 The "href" Attribute
	The "href" attribute contains the a URI of the service. atom:service
	elements MUST have a "href" attribute, whose value MUST be a URI
	reference [RFC3986].
	xml:base processing MUST be applied to the "href" attribute.
	3.5 Identity Constructs
	An Identity construct is an element whose content conveys a		[0-9]{8}T[0-9]{2}:[0-9]{2}:[0-9]{2}(\.[0-9]+)
	permanent, universally unique identifier for the construct's parent.		?(Z|[\+\-][0-9]{2}:[0-9]{2})
	Its content MUST be a URI, as defined by [RFC3986]. Note that the
	definition of "URI" excludes relative references.
	When an Atom document is relocated, migrated, syndicated,		As a result, the date values conform to the following specifications:
	republished, exported or imported, the content of its Identity		[RFC3339], [W3C.REC-xmlschema-2-20041028],
	construct MUST NOT change. Put another way, an Identity construct		[W3C.NOTE-datetime-19980827], and [ISO.8601.1988].
	pertains to all instantiations of a particular Atom entry or feed;
	revisions retain the same content in their Identity constructs.
	atomIdentityConstruct =		atomDateConstruct =
	atomCommonAttributes,		atomCommonAttributes,
	(atomUri)		xsd:dateTime
	3.5.1 Dereferencing Identity Constructs
	The content of an Identity construct MAY be dereferencable (e.g. an
	HTTP URI). However, processors MUST NOT assume it to be
	dereferencable.
	The content of an Identity construct MUST be created in a way that
	assures uniqueness, and it is suggested that the Identity construct
	be stored along with the associated resource.
	Because of the risk of confusion between URIs that would be
	equivalent if dereferenced, the following normalization strategy is
	strongly encouraged when generating Identity constructs:
	o Provide the scheme in lowercase characters.
	o Provide the host, if any, in lowercase characters.
	o Only perform percent-encoding where it is essential.
	o Use uppercase A-through-F characters when percent-encoding.
	o Prevent dot-segments appearing in paths.
	o For schemes that define a default authority, use an empty
	authority if the default is desired.
	o For schemes that define an empty path to be equivalent to a path
	of "/", use "/".
	o For schemes that define a port, use an empty port if the default
	is desired.
	o Preserve empty fragment identifiers and queries.
	o Ensure that all portions of the URI are UTF-8 encoded NFC form
	Unicode strings.
	3.5.2 Comparing Identity Constructs
	Instances of Identity constructs can be compared to determine whether
	an entry or feed is the same as one seen before. Processors MUST
	compare Identity constructs on a character-by-character basis in a
	case-sensitive fashion.
	As a result, two URIs that resolve to the same resource but are not
	character-for-character identical will be considered different for
	the purposes of Identifier comparison.
	For example, "http://www.example.org/thing",		4. Atom Element Definitions
	"http://www.example.org/Thing", "http://www.EXAMPLE.org/thing" and
	"HTTP://www.example.org/thing" will all be considered different
	identifiers, despite their differences in case.
	Likewise, "http://www.example.com/~bob",		4.1 Container Elements
	"http://www.example.com/%7ebob" and "http://www.example.com/%7Ebob"
	will all be considered different identifiers, because URI %-escaping
	is significant for the purposes of comparison.
	4. Element Definitions		4.1.1 The "atom:feed" Element
	4.1 The "atom:feed" Element		[[anchor21: Substantially changed from format-05, review carefully.]]
	The "atom:feed" element is the document (i.e., top-level) element of		The "atom:feed" element is the document (i.e., top-level) element of
	an Atom Feed Document, acting as a container for metadata and data		an Atom Feed Document, acting as a container for metadata and data
	associated with the feed. Its first element child MUST be atom:head,		associated with the feed. Its element children consist of one or
	which MAY be followed zero or more atom:entry child elements.		more metadata elements followed by zero or more atom:entry child
			elements.
			This specification assigns no significance to the order of atom:entry
			elements within the feed.
	atomFeed =		atomFeed =
	element atom:feed {		element atom:feed {
	atomCommonAttributes,		atomCommonAttributes,
	atomVersionAttribute,		(atomAuthor?
	(atomHead		& atomCategory*
	& atomEntry*
	& anyElement*)
	}
	4.1.1 The "version" Attribute
	atom:feed elements MUST have a "version" attribute whose content
	indicates the version of the Atom specification that the feed
	conforms to. The content of this attribute is unstructured text.
	The version identifier for this specification is
	"draft-ietf-atompub-format-05: do not deploy".
	atomVersionAttribute =
	attribute version {"draft-ietf-atompub-format-05 : do not deploy"}
	4.2 The "atom:head" Element
	The atom:head element acts as a container for metadata about the feed
	itself.
	The atom:head element MAY contain any namespace-qualified
	[W3C.REC-xml-names-19990114] elements as children. This
	specification assigns no significance to the order of appearance of
	the child elements of atom:head.
	atomHead =
	element atom:head {
	atomCommonAttributes,
	(atomTitle
	& atomUpdated
	& atomLink+
	& atomId?
	& atomAuthor?
	& atomContributor*		& atomContributor*
	& atomTagline?
	& atomGenerator?
	& atomInfo?
	& atomCopyright?		& atomCopyright?
	& atomCategory*		& atomGenerator?
	& atomIntrospection?		& atomIcon?
	& atomPost?		& atomId?
	& anyElement*)		& atomImage?
			& atomLink+
			& atomSubtitle?
			& atomTitle
			& atomUpdated
			& anyElement* ),
			atomEntry*
	}		}
	The following child elements are defined by this specification (note		The following child elements are defined by this specification (note
	that the presence of some of these elements is required):		that the presence of some of these elements is required):
	o atom:head elements MUST contain exactly one atom:title element.		o atom:feed elements MUST contain exactly one atom:author element,
	o atom:head elements MUST contain at least one atom:link element
	with a rel attribute value of "alternate".
	o atom:head elements MUST NOT contain more than one atom:link
	element with a rel attribute value of "alternate" that has the
	same type attribute value. If a feed's atom:link element with
	type="alternate" resolves to an HTML document, then that document
	SHOULD have a autodiscovery link element [Atom-autodiscovery] that
	reflects back to the feed. atom:head elements MAY contain
	additional atom:link elements beyond those described above.
	o atom:head elements MUST contain exactly one atom:author element,
	UNLESS all of the atom:feed element's child atom:entry elements		UNLESS all of the atom:feed element's child atom:entry elements
	contain an atom:author element. atom:head elements MUST NOT		contain an atom:author element. atom:feed elements MUST NOT
	contain more than one atom:author element. [[inheritance]]		contain more than one atom:author element. [[anchor22:
	o atom:head elements MUST NOT contain more than one an		inheritance]]
	atom:contributor element.		o atom:feed elements MAY contain any number of atom:category
	o atom:head elements MUST NOT contain more than one an
	atom:copyright element.
	o atom:head elements MUST NOT contain more than one an atom:id
	element.
	o atom:head elements MUST contain exactly one atom:updated element.
	o atom:head elements MAY contain any number of atom:category
	elements.		elements.
	o atom:head elements MUST NOT contain more than one atom:post
	element.
	o atom:head elements MUST NOT contain more than one		o atom:feed elements MAY contain any number of atom:contributor
	atom:introspection element.		elements.
	o atom:head elements MUST NOT contain more than one atom:tagline		o atom:feed elements MUST NOT contain more than one atom:copyright
	element.		element.
	o atom:head elements MUST NOT contain more than one atom:generator		o atom:feed elements MUST NOT contain more than one atom:generator
	element.		element.
	o atom:head elements MUST NOT contain more than one atom:info		o atom:feed elements MUST NOT contain more than one atom:icon
	element.		element.
			o atom:feed elements MUST NOT contain more than one atom:image
			element.
			o atom:feed elements MUST NOT contain more than one atom:id element.
			o atom:feed elements MUST contain at least one atom:link element
			with a relation of "alternate".
			o atom:feed elements SHOULD contain one atom:link element with a rel
			attribute value of "self" and SHOULD contain a href attribute with
			an absolute URI as its value. This URI identifies the feed and a
			representation equivalent to the feed.
			o atom:feed elements MUST NOT contain more than one atom:link
			element with a rel attribute value of "alternate" that has the
			same type attribute value. If a feed's atom:link element with
			type="alternate" resolves to an HTML document, then that document
			SHOULD have a autodiscovery link element [Atom-autodiscovery] that
			reflects back to the feed. atom:feed elements MAY contain
			additional atom:link elements beyond those described above.
			o atom:feed elements MUST NOT contain more than one atom:subtitle
			element.
			o atom:feed elements MUST contain exactly one atom:title element.
			o atom:feed elements MUST contain exactly one atom:updated element.
			o atom:feed elements MUST NOT contain atom:entry elements with
			identical atom:id values.
	4.2.1 Usage of "atom:head" within "atom:entry"		4.1.2 The "atom:entry" Element
	In this case, the atom:head element acts as a container for metadata
	about the feed within which the entry was created.
	If an atom:entry is copied into one feed from another feed, then the
	atom:head element of the source feed SHOULD be inserted into the
	atom:entry unless the entry, as copied, already contains an atom:head
	element. If the atom:entry already contains an atom:head, then that
	atom:head SHOULD be copied without modification.
	[[ ... example ... ]]
	4.3 The "atom:entry" Element
	The "atom:entry" element represents an individual entry. This		The "atom:entry" element represents an individual entry, acting as a
			container for metadata and data associated with the entry. This
	element can appear as a child of the atom:feed element, or it can		element can appear as a child of the atom:feed element, or it can
	appear as the document (i.e., top-level) element of a standalone Atom		appear as the document (i.e., top-level) element of a standalone Atom
	Entry Document.		Entry Document.
	When appearing in an Atom Entry Document, atom:entry elements MUST
	have a "version" attribute whose content indicates the version of the
	Atom specification that the entry conforms to.
	The version identifier for this specification is
	"draft-ietf-atompub-format-05: do not deploy".
	The atom:entry element MAY contain any namespace-qualified		The atom:entry element MAY contain any namespace-qualified
	[W3C.REC-xml-names-19990114] elements as children. This		[W3C.REC-xml-names-19990114] elements as children. This
	specification assigns no significance to the order of appearance of		specification assigns no significance to the order of appearance of
	the child elements of atom:entry.		the child elements of atom:entry.
	atomEntry =		atomEntry =
	element atom:entry {		element atom:entry {
	atomCommonAttributes,		atomCommonAttributes,
	atomVersionAttribute?,		(atomAuthor?
	(atomTitle		& atomCategory*
			& atomContent?
			& atomContributor*
			& atomCopyright?
	& atomId		& atomId
	& atomLink*		& atomLink*
	& atomUpdated
	& atomPublished?		& atomPublished?
	& atomAuthor?		& atomSourceFeed?
	& atomContributor*
	& atomHost?
	& atomCopyright?
	& atomCategory*
	& atomEdit?
	& atomSummary?		& atomSummary?
	& atomContent?		& atomTitle
	& atomHead?		& atomUpdated &
	& anyElement*)		anyElement*)
	}		}
	The following child elements are defined by this specification (note		The following child elements are defined by this specification (note
	that it requires the presence of some of these elements):		that it requires the presence of some of these elements):
	o atom:entry elements MUST have exactly one "atom:title" element.		o atom:entry elements MUST contain exactly one atom:author element,
			unless, in an Atom Feed Document, the atom:feed element contains
			an atom:author element itself. atom:entry elements MUST NOT
			contain more than one atom:author element. [[anchor24: What if
			there's a source-feed element? This is busted. We should make
			author required for atom:feed and optional for atom:entry. No
			inheritance co-constraints required. --R. Sayre]]
			o atom:entry elements MAY contain any number of atom:category
			elements.
			o atom:entry elements MAY contain any number of atom:contributor
			elements.
			o atom:entry elements MUST NOT contain more than one atom:copyright
			element.
	o atom:entry elements MUST contain exactly one atom:id element.		o atom:entry elements MUST contain exactly one atom:id element.
	o atom:entry elements that contain no child atom:content element		o atom:entry elements that contain no child atom:content element
	MUST contain at least one atom:link element with a rel attribute		MUST contain at least one atom:link element with a rel attribute
	value of "alternate". atom:entry elements MUST NOT contain more		value of "alternate". [[anchor25: "atom:entry elements MUST NOT
	than one atom:link element with a rel attribute value of		contain more than one atom:link element with a rel attribute value
	"alternate" that has the same type attribute value. atom:entry		of "alternate" that has the same type attribute value." This
			requirement predates @hreflang. Keep it? --R. Sayre]] atom:entry
	elements MAY contain additional atom:link elements beyond those		elements MAY contain additional atom:link elements beyond those
	described above.		described above.
	o atom:entry elements MUST contain exactly one atom:updated element.
	o atom:entry elements MUST NOT contain more than one atom:published		o atom:entry elements MUST NOT contain more than one atom:published
	element.		element.
	o atom:entry elements MUST contain exactly one atom:author element,
	unless, in an Atom Feed Document, the atom:head element contains
	an atom:author element itself. atom:entry elements MUST NOT
	contain more than one atom:author element.
	o atom:entry elements MUST NOT contain more than one		o atom:entry elements MUST NOT contain more than one
	atom:contributor element.		atom:source-feed element.
	o atom:entry elements MUST NOT contain more than one atom:host
	element.
	o atom:entry elements MUST NOT contain more than one atom:copyright
	element.
	o atom:entry elements MAY contain any number of atom:category
	elements.
	o atom:entry elements MUST contain an atom:summary element in any of		o atom:entry elements MUST contain an atom:summary element in any of
	the following cases:		the following cases: [[anchor26: Do these requirements reflect the
			WG's decisions? --R. Sayre]]
	* the atom:entry element contains no atom:content element.		* the atom:entry element contains no atom:content element.
	* the atom:entry contains an atom:content which has a "src"		[[anchor27: Net result: Atom entries MUST have an atom:summary
			or an atom:content element.]]
			* the atom:entry contains an atom:content that has a "src"
	attribute (and is thus empty).		attribute (and is thus empty).
	* the atom:entry contains content which is encoded in Base64;		* the atom:entry contains content that is encoded in Base64; i.e.
	i.e. the "type" attribute of atom:content is a MIME media type		the "type" attribute of atom:content is a MIME media type
	[RFC2045] and does not begin with "text/" nor end with "+xml".		[RFC2045] and does not begin with "text/" nor end with "+xml".
	o atom:entry elements MUST NOT contain more than one atom:summary		o atom:entry elements MUST NOT contain more than one atom:summary
	element.		element.
	o atom:entry elements MUST NOT contain more than one atom:edit		o atom:entry elements MUST have exactly one "atom:title" element.
	element.		o atom:entry elements MUST contain exactly one atom:updated element.
	o atom:entry elements MUST NOT contain more than one atom:head
	element.
	4.4 The "atom:title" Element		4.1.3 The "atom:content" Element
	The "atom:title" element is a Text construct that conveys a		The "atom:content" element either contains or links to the content of
	human-readable title for an entry or feed.		the entry. Except for the "type" and "src" attributes, the content
			of atom:content is language-sensitive. atom:entry elements MUST
			contain zero or one atom:content elements.
	atomTitle = element atom:title { atomTextConstruct }		atomInlineTextContent =
			element atom:content {
			atomCommonAttributes,
			attribute type { "text" | "html" | atomMediaType }?,
			(text)*
			}
	4.5 The "atom:id" Element		atomInlineXHTMLContent =
			element atom:content {
			atomCommonAttributes,
			attribute type {
			"xhtml" |
			atomMediaType
			}?,
			(text|anyElement)*
			}
	The "atom:id" element is an Identity construct that conveys a		atomOutOfLineContent =
	permanent, universally unique identifier for an entry or feed.		element atom:content {
			atomCommonAttributes,
			attribute type {
			"text" |
			"html" |
			"xhtml" |
			atomMediaType }?,
			attribute src { atomUri },
			empty
			}
	atomId = element atom:id { atomIdentityConstruct }		atomContent =
			atomInlineTextContent |
			atomInlineXHTMLContent |
			atomOutOfLineContent
	4.6 The "atom:link" Element		4.1.3.1 The "type" attribute
	The atom:link element is an empty element that defines a reference		atom:content MAY have a "type" attribute. When present, the value
	from an Atom Document to a Web resource.		MAY be one of "text", "html", or "xhtml". Failing that, it MUST be a
			MIME media type [RFC2045] with a discrete top-level type (see Section
			5 of [RFC2045]). If the type attribute is not provided, Atom
			Processors MUST behave as though it were present with a value of
			"text".
	atomLink = element atom:link {		4.1.3.2 The "src" attribute
			atom:content MAY have a "src" attribute, whose value MUST be an IRI
			reference [RFC3987]. If the "src" attribute is present, Atom
			Processors MAY use the IRI to retrieve the content. If the "src"
			attribute is present, atom:content MUST be empty. That is to say,
			the content may be retrievable using "src=" IRI, or it may be
			contained within atom:content, but not both.
			If the "src" attribute is present, the "type" attribute SHOULD be
			provided and MUST be a MIME media type [RFC2045], rather than "text",
			"html", or "xhtml". The value is advisory; that is to say, upon
			dereferencing the IRI to retrieve the content, if the server
			providing that content also provides a media type, the
			server-provided media type is authoritative.
			If the value of type begins with "text/" or ends with "+xml", the
			content SHOULD be local; that is to say, no "src" attribute should be
			provided. [[anchor31: J. Reschke: I'm not sure I understand what
			this is for. It seems to discourage putting XML data out-of-band.
			Why? ... Explaining the issue instead of just trying to enforce it
			may lead to better results...]]
			4.1.3.3 Processing Model
			Atom Documents MUST conform to the following rules. Atom Processors
			MUST interpret atom:content according to the first applicable rule.
			1. If the value of "type" is "text", the content of atom:content
			MUST NOT contain child elements. Such text is intended to be
			presented to humans in a readable fashion. Thus, Atom Processors
			MAY display it using normal text rendering techniques such as
			proportional fonts, white-space collapsing, and justification.
			2. If the value of "type" is "html", the content of atom:content
			MUST NOT contain child elements, and SHOULD be suitable for
			handling as HTML [W3C.REC-html401-19991224]. The HTML markup
			must be escaped; for example, "<br>" as "&lt;br>". The HTML
			markup SHOULD be such that it could validly appear directly
			within an HTML <DIV> element. Atom Processors that display the
			content SHOULD use the markup to aid in displaying it.
			3. If the value of "type" is "xhtml", the content of atom:content
			MUST be a single XHTML div element
			[W3C.REC-xhtml-basic-20001219]. The XHTML div MUST contain XHTML
			text and markup that could validly appear within an XHTML div
			element. The XHTML div element itself MUST NOT be considered
			part of the content. Atom Processors that display the content
			MAY use the markup to aid in displaying it. Escaped markup is
			interpreted as a text representation of markup, and MUST NOT be
			interpreted as markup itself.
			4. If the value of "type" ends with "+xml" or "/xml"
			(case-insensitive), the content of atom:content may include child
			elements, and SHOULD be suitable for handling as the indicated
			media type. If the "src" attribute is not provided, this would
			normally mean that the "atom:content" element would contain a
			single child element which would serve as the root element of the
			XML document of the indicated type.
			5. If the value of "type" begins with "text/" (case-insensitive),
			the content of atom:content MUST NOT contain child elements.
			6. For all other values of "type", the content of atom:content MUST
			be a valid Base64 encoding [RFC3548], which when decoded SHOULD
			be suitable for handling as the indicated media type. In this
			case, the characters in the Base64 encoding may be preceded and
			followed in the atom:content element by whitespace, and lines are
			separated by a single newline (U+000A) character.
			4.1.3.4 Examples
			XHTML inline:
			...
			<content type="xhtml">
			<div xmlns="http://www.w3.org/1999/xhtml">
			This is <b>XHTML</b> content.
			</div>
			</content>
			...
			<content type="xhtml">
			<xhtml:div xmlns:xhtml="http://www.w3.org/1999/xhtml">
			This is <xhtml:b>XHTML</xhtml:b> content.
			</xhtml:div>
			</content>
			...
			The following example assumes that the XHTML namespace has been bound
			to the "xh" prefix earlier in the document:
			...
			<content type="xhtml">
			<xh:div>
			This is <xh:b>XHTML</xh:b> content.
			</xh:div>
			</content>
			...
			4.2 Metadata Elements
			4.2.1 The "atom:author" Element
			The "atom:author" element is a Person construct that indicates the
			author of the entry or feed.
			atomAuthor = element atom:author { atomPersonConstruct }
			4.2.2 The "atom:category" Element
			The "atom:category" element conveys information about a category
			associated with an entry or feed.
			atomCategory =
			element atom:category {
			atomCommonAttributes, attribute term { text },
			attribute scheme { atomUri }?,
			attribute label { text }?,
			empty
			}
			4.2.2.1 The "term" Attribute
			The "term" attribute is a string that identifies the category to
			which the entry or feed belongs. Category elements MUST have a
			"term" attribute.
			4.2.2.2 The "scheme" Attribute
			The "scheme" attribute is an IRI that identifies a categorization
			scheme. Category elements MAY have a "scheme" attribute.
			4.2.2.3 The "label" attribute
			The "label" attribute provides a human-readable label for display in
			end-user applications. The content of the "label" attribute is
			language-sensitive. Category elements MAY have a "label" attribute.
			4.2.3 The "atom:contributor" Element
			The "atom:contributor" element is a Person construct that indicates a
			person or other entity who contributed to the entry or feed.
			atomContributor = element atom:contributor { atomPersonConstruct }
			4.2.4 The "atom:copyright Element
			The "atom:copyright" element is a Text construct that conveys a
			human-readable copyright statement for an entry or feed.
			atomCopyright = element atom:copyright { atomTextContstruct }
			The atom:copyright element SHOULD NOT be used to convey
			machine-readable licensing information.
			If an atom:entry element does not contain an atom:copyright element,
			then the atom:copyright element of the containing atom:feed element's
			atom:head element, if present, is considered to apply to the entry.
			4.2.5 The "atom:generator" Element
			The "atom:generator" element's content identifies the agent used to
			generate a feed, for debugging and other purposes.
			atomGenerator =
			element atom:generator {
			atomCommonAttributes,
			attribute uri { atomUri }?,
			attribute version { text }?,
			text
			}
			The content of this element, when present, MUST be a string that is a
			human-readable name for the generating agent.
			The atom:generator element MAY have a "uri" attribute whose value
			MUST be an IRI reference [RFC3987]. When dereferenced, that IRI
			SHOULD produce a representation that is relevant to that agent.
			The atom:generator element MAY have a "version" attribute that
			indicates the version of the generating agent. When present, its
			value is unstructured text.
			4.2.6 The "atom:icon" Element
			The "atom:icon" element's content is an IRI [RFC3987] which
			identifies an image which provides iconic visual identification for a
			feed. The image SHOULD have an aspect ratio of one (horizontal) to
			one (vertical), and should be suitable for presentation at a small
			size.
			atomIcon = element atom:icon { atomCommonAttributes, (atomUri) }
			4.2.7 The "atom:id" Element
			[[anchor45: Substantially changed from format-05, review carefully]]
			The "atom:id" element conveys a permanent, universally unique
			identifier for an entry or feed.
			atomId = element atom:id { atomCommonAttributes, (atomUri) }
			Its content MUST be an IRI, as defined by [RFC3987]. Note that the
			definition of "IRI" excludes relative references. Though the IRI
			might use a dereferencable scheme, Atom Processors MUST NOT assume it
			can be dereferenced.
			When an Atom document is relocated, migrated, syndicated,
			republished, exported or imported, the content of its atom:id element
			MUST NOT change. Put another way, an atom:id element pertains to all
			instantiations of a particular Atom entry or feed; revisions retain
			the same content in their atom:id elements.
			The content of an atom:id element MUST be created in a way that
			assures uniqueness; it is suggested that the atom:id element be
			stored along with the associated resource.
			Because of the risk of confusion between IRIs that would be
			equivalent if dereferenced, the following normalization strategy is
			strongly encouraged when generating atom:id elements:
			o Provide the scheme in lowercase characters.
			o Provide the host, if any, in lowercase characters.
			o Only perform percent-encoding where it is essential.
			o Use uppercase A-through-F characters when percent-encoding.
			o Prevent dot-segments appearing in paths.
			o For schemes that define a default authority, use an empty
			authority if the default is desired.
			o For schemes that define an empty path to be equivalent to a path
			of "/", use "/".
			o For schemes that define a port, use an empty port if the default
			is desired.
			o Preserve empty fragment identifiers and queries.
			o Ensure that all components of the IRI are appropriately
			character-normalized, e.g. by using NFC or NFKC.
			4.2.7.1 Comparing atom:id
			Instances of atom:id elements can be compared to determine whether an
			entry or feed is the same as one seen before. Processors MUST
			compare atom:id elements on a character-by-character basis (in a
			case-sensitive fashion). Comparison operations MUST be based solely
			on the IRI character strings, and MUST NOT rely on dereferencing the
			IRIs.
			As a result, two IRIs that resolve to the same resource but are not
			character-for-character identical will be considered different for
			the purposes of identifier comparison.
			For example:
			http://www.example.org/thing
			http://www.example.org/Thing
			http://www.EXAMPLE.org/thing
			HTTP://www.example.org/thing
			are four distinct identifiers, despite their differences in case.
			Likewise,
			http://www.example.com/~bob
			http://www.example.com/%7ebob
			http://www.example.com/%7Ebob
			are three distinct identifiers, because IRI %-escaping is significant
			for the purposes of comparison.
			4.2.8 The "atom:image" Element
			The "atom:image" element's content is an IRI [RFC3987] which
			identifies an image which provides visual identification for a feed.
			The image SHOULD have an aspect ratio of 2 (horizontal) to 1
			(vertical).
			atomImage = element atom:image { atomCommonAttributes, (atomUri) }
			4.2.9 The "atom:link" Element
			The "atom:link" element is an empty element that defines a reference
			from an entry or feed to a Web resource.
			atomLink =
			element atom:link {
	atomCommonAttributes,		atomCommonAttributes,
	attribute href { atomUri },		attribute href { atomUri },
	attribute rel { atomNCName | atomUri }?,		attribute rel { atomNCName | atomUri }?,
	attribute type { atomMediaType }?,		attribute type { atomMediaType }?,
	attribute hreflang { atomLanguageTag }?,		attribute hreflang { atomLanguageTag }?,
	attribute title { text }?,		attribute title { text }?,
	attribute length { text }?,		attribute length { text }?,
	empty		empty
	}		}
	4.6.1 The "href" Attribute		4.2.9.1 The "href" Attribute
	The "href" attribute contains the link's URI. Link constructs MUST		The "href" attribute contains the link's IRI. atom:link elements
	have a href attribute, whose value MUST be a URI reference [RFC3986].		MUST have a href attribute, whose value MUST be a IRI reference
			[RFC3987].
	xml:base [W3C.REC-xmlbase-20010627] processing MUST be applied to the		xml:base [W3C.REC-xmlbase-20010627] processing MUST be applied to the
	href attribute's content.		href attribute's content.
	4.6.2 The "rel" Attribute		4.2.9.2 The "rel" Attribute
	Link elements MAY have an "rel" attribute that indicates the link		atom:link elements MAY have an "rel" attribute that indicates the
	relation type. If the "rel" attribute is not present, the link		link relation type. If the "rel" attribute is not present, the link
	element MUST be interpreted as if the link relation type is		element MUST be interpreted as if the link relation type is
	"alternate".		"alternate".
	rel_attribute = segment-nz-nc / URI		rel_attribute = segment-nz-nc / IRI
	The value of "rel" MUST be either a name, which is non-empty and does		The value of "rel" MUST be either a name that is non-empty and does
	not contain any colon (":") characters, or a URI [RFC3986]. Note		not contain any colon (":") characters, or a IRI [RFC3987]. Note
	that use of a relative reference is not allowed. If a name is given,		that use of a relative reference is not allowed. If a name is given,
	implementations MUST consider the link relation type to be equivalent		implementations MUST consider the link relation type to be equivalent
	to the same name registered within the IANA Registry of Link		to the same name registered within the IANA Registry of Link
	Relations Section 9, and thus the URI that would be obtained by		Relations Section 7, and thus the IRI that would be obtained by
	appending the value of the rel attribute to the string		appending the value of the rel attribute to the string
	"http://www.iana.org/assignments/relation/". The value of "rel"		"http://www.iana.org/assignments/relation/". The value of "rel"
	describes the meaning of the link, but does not impose any behavioral		describes the meaning of the link, but does not impose any behavioral
	requirements on implementations.		requirements on implementations.
	This document defines two initial values for the Registry of Link		This document defines five initial values for the Registry of Link
	Relations:		Relations:
	The value "alternate" signifies that the URI in the value of the href		The value "alternate" signifies that the IRI in the value of the href
	attribute identifies an alternate version of the resource described		attribute identifies an alternate version of the resource described
	by the containing element.		by the containing element.
	The value "related" signifies that the URI in the value of the href		The value "related" signifies that the IRI in the value of the href
	attribute identifies a resource related to the resource described by		attribute identifies a resource related to the resource described by
	the containing atom:feed or atom:entry element. For example, the		the containing element. For example, the feed for a site that
	feed for a site which discusses the performance of the search engine		discusses the performance of the search engine at
	at "http://search.example.com" might contain, as a child of		"http://search.example.com" might contain, as a child of atom:feed:
	atom:head:
	<link rel="related" href="http://search.example.com/">		<link rel="related" href="http://search.example.com/">
	An identical link might appear as a child of any atom:entry whose		An identical link might appear as a child of any atom:entry whose
	content contains a discussion of that same search engine.		content contains a discussion of that same search engine.
	4.6.3 The "type" Attribute		The value "self" signifies that the IRI in the value of the href
			attribute identifies a resource equivalent to the containing element.
			The value "enclosure" signifies that the IRI in the value of the href
			attribute identifies a related resource which is potentially large in
			size and may require special handling by consuming software. For
			Link constructs with rel="enclosure", the length attribute SHOULD be
			provided.
			The value "via" signifies that the IRI in the value of the href
			attribute identifies a resource that is the source of the information
			provided in the containing element.
			4.2.9.3 The "type" Attribute
	Link elements MAY have a type attribute, whose value MUST conform to		Link elements MAY have a type attribute, whose value MUST conform to
	the syntax of a MIME media type [RFC2045].		the syntax of a MIME media type [RFC2045].
	The type attribute's value is an advisory media type; it is a hint		The type attribute's value is an advisory media type; it is a hint
	about the type of the representation which is expected to be returned		about the type of the representation that is expected to be returned
	when the value of the href attribute is dereferenced. Note that the		when the value of the href attribute is dereferenced. Note that the
	type attribute does not override the actual media type returned with		type attribute does not override the actual media type returned with
	the representation.		the representation.
	4.6.4 The "hreflang" Attribute		4.2.9.4 The "hreflang" Attribute
	The "hreflang" attribute's content describes the language of the		The "hreflang" attribute's content describes the language of the
	resource pointed to by the href attribute. When used together with		resource pointed to by the href attribute. When used together with
	the rel="alternate", it implies a translated version of the entry.		the rel="alternate", it implies a translated version of the entry.
	Link elements MAY have an hreflang attribute, whose value MUST be a		Link elements MAY have an hreflang attribute, whose value MUST be a
	language tag [RFC3066].		language tag [RFC3066].
	4.6.5 The "title" Attribute		4.2.9.5 The "title" Attribute
	The "title" attribute conveys human-readable information about the		The "title" attribute conveys human-readable information about the
	link. Link elements MAY have a title attribute.		link. The content of the "title" attribute is language sensitive.
			Link elements MAY have a title attribute.
	4.6.6 The "length" Attribute		4.2.9.6 The "length" Attribute
	The "length" attribute indicates an advisory length of the linked		The "length" attribute indicates an advisory length of the linked
	content in octets; it is a hint about the content length of the		content in octets; it is a hint about the content length of the
	representation returned when the URI in the href attribute is		representation returned when the IRI in the href attribute is
	dereferenced. Note that the length attribute does not override the		dereferenced. Note that the length attribute does not override the
	actual content length of the representation as reported by the		actual content length of the representation as reported by the
	underlying protocol.		underlying protocol.
	Link elements MAY have a length attribute.		Link elements MAY have a length attribute.
	4.7 The "atom:updated" Element		4.2.10 The "atom:published" Element
	The "atom:updated" element is a Date construct indicating the most
	recent instant in time when an entry or feed was modified in a way
	the producer considers significant. Therefore, not all modifications
	necessarily result in a changed atom:updated value.
	Publishers MAY change the value of this element over time.
	Processors MAY present entries sorted using this value. Processors
	MAY choose not to present entries until the instant in time specified
	in the atom:updated element has passed.
	atomUpdated = element atom:updated { atomDateConstruct }
	4.8 The "atom:published" Element
	The "atom:published" element is a Date construct indicating an		The "atom:published" element is a Date construct indicating an
	instant in time associated with an event early in the life cycle of		instant in time associated with an event early in the life cycle of
	the entry. Typically, atom:published will be associated with the		the entry. Typically, atom:published will be associated with the
	initial creation or first availability of the resource.		initial creation or first availability of the resource.
	Processors MAY present entries sorted using this value. Processors		atomPublished = element atom:published { atomDateConstruct }
	MAY choose not to present entries until the instant in time specified
	in the atom:published element has passed.
	4.9 The "atom:author" Element
	The "atom:author" element is a Person construct that indicates the
	default author of the an entry or feed
	atomAuthor = element atom:author { atomPersonConstruct }
	4.10 The "atom:contributor" Element
	The "atom:contributor" element is a Person construct that indicates a
	person or other entity who contributes to the entry.
	atomContributor = element atom:contributor { atomPersonConstruct }
	4.11 The "atom:host" Element
	The "atom:host" element's content conveys a domain name or network
	address associated with an entry's origin. Its content MUST be a
	domain name [RFC1035], a dotted-decimal IPv4 address [RFC0791], or a
	colon-delimited IPv6 address [RFC2460].
	4.12 The "atom:copyright" Element
	The "atom:copyright" element is a Text construct that conveys a
	human-readable copyright statement for an entry or feed.
	The atom:copyright element SHOULD NOT be used to convey
	machine-readable licensing information.
	If an atom:entry element does not contain an atom:copyright element,
	then the atom:copyright element of the containing atom:feed element's
	atom:head element, if present, should be considered to apply to the
	entry.
	4.13 The "atom:category" Element		4.2.11 The "atom:source-feed" Element
	Category elements contain information about a category to which an		If an atom:entry is copied from one feed into another feed, then the
	Atom feed or entry is associated.		source atom:feed's metadata (all child elements of atom:feed other
			than the atom:entry elements) MAY be preserved within the copied
			entry by adding an atom:source-feed child element, if it is not
			already present in the entry, and including some or all of the source
			feed's metadata elements as the atom:source-feed element's children.
			Such metadata SHOULD be preserved if the source atom:feed contains
			any of the child elements atom:author, atom:contributor,
			atom:copyright, or atom:category and those child elements are not
			present in the source atom:entry.
	atomCategory = element atom:category {		atomSourceFeed =
			element atom:source-feed {
	atomCommonAttributes,		atomCommonAttributes,
	attribute term { text },		(atomAuthor?
	attribute scheme { atomUri }?,		& atomCategory*
	attribute label { text }?,		& atomContributor*
	empty		& atomCopyright?
			& atomGenerator?
			& atomIcon?
			& atomId?
			& atomImage?
			& atomLink+
			& atomSubtitle?
			& atomTitle
			& atomUpdated
			& anyElement* )
	}		}
	4.13.1 The "term" Attribute		4.2.12 The "atom:subtitle" Element
	The "term" attribute is a string which identifies the category to
	which the entry or feed belongs. Category elements MUST have a
	"term" attribute.
	4.13.2 The "scheme" Attribute
	The "scheme" attribute is a URI that identifies a categorization
	scheme. Category elements MAY have a "scheme" attribute.
	4.13.3 The "label" attribute		The "atom:subtitle" element is a Text construct that conveys a
			human-readable description or subtitle for a feed.
	The "label" attribute provides a human-readable label that may be		atomSubtitle = element atom:subtitle { atomTextConstruct }
	displayed in end-user applications. Category elements MAY have a
	"label" attribute.
	4.14 The "atom:summary" Element		4.2.13 The "atom:summary" Element
	The "atom:summary" element is a Text construct that conveys a short		The "atom:summary" element is a Text construct that conveys a short
	summary, abstract or excerpt of an entry.		summary, abstract or excerpt of an entry.
	atomSummary = element atom:summary { atomTextConstruct }		atomSummary = element atom:summary { atomTextConstruct }
	4.15 The "atom:content" Element		4.2.14 The "atom:title" Element
	The "atom:content" element either contains or links to the content of
	the entry. atom:entry elements MUST contain zero or one atom:content
	elements.
	atomInlineTextContent =
	element atom:content {
	atomCommonAttributes,
	attribute type { "TEXT" | "HTML" | atomMediaType }?,
	(text)*
	}
	atomInlineXHTMLContent =
	element atom:content {
	atomCommonAttributes,
	attribute type { "XHTML" | atomMediaType }?,
	(text|anyElement)*
	}
	atomOutOfLineContent =
	element atom:content {
	atomCommonAttributes,
	attribute type { "TEXT" | "HTML" | "XHTML" | atomMediaType }?,
	attribute src { atomUri },
	empty
	}
	atomContent = atomInlineTextContent
	| atomInlineXHTMLContent
	| atomOutOfLineContent
	4.15.1 The "type" attribute
	atom:content MAY have a "type" attribute, When present, the value MAY
	be one of "TEXT", "HTML", or "XHTML". Failing that, it MUST be a
	MIME media type [RFC2045] in which, to use the terminology of Section
	5 of [RFC2045], the top level is a discrete type. If the type
	attribute is not provided, software MUST behave as though it were
	present with a value of "TEXT".
	4.15.2 The "src" attribute
	atom:content MAY have a "src" attribute, whose value MUST be a URI
	reference [RFC3986]. If the "src" attribute is present, software MAY
	use the URI to retrieve the content. If the "src" attribute is
	present, atom:content MUST be empty. That is to say, the content may
	be retrievable using "src=" URI, or it may be contained within
	atom:content, but not both.
	If the "src" attribute is present, the "type" attribute SHOULD be
	provided and MUST be a MIME media type [RFC2045], rather than "TEXT",
	"HTML", or "XHTML". The value is advisory; that is to say, upon
	dereferencing the URI to retrieve the content, if the server
	providing that content also provides a media type, the
	server-provided media type is authoritative.
	If the value of type begins with "text/" or ends with "+xml", the
	content SHOULD be local; that is to say, no "src" attribute should be
	provided.
	4.15.3 Processing Model
	Software MUST apply the following rules in the order below to
	ascertain the rules governing the content of "atom:content".
	1. If the value is "TEXT", the content of atom:content MUST NOT
	contain child elements. Such text is intended to be presented to
	humans in a readable fashion. Thus, software MAY display it
	using normal text rendering techniques such as proportional
	fonts, white-space collapsing, and justification.
	2. If the value of "type" is "HTML", the content of atom:content
	MUST NOT contain child elements, and SHOULD be suitable for
	handling by software that knows HTML. The HTML markup must be
	escaped; for example, "<br>" as "&lt;br>". The HTML markup
	SHOULD be such that it could validly appear directly within an
	HTML <DIV> element. Receiving software which displays the
	content SHOULD use the markup to aid in displaying it.
	3. If the value of "type" is "XHTML", the content of atom:content
	MAY contain child elements. The content SHOULD be XHTML text and
	markup that could validly appear directly within an xhtml:div
	element. Receiving software which displays the content SHOULD
	use the markup to aid in displaying it. Escaped markup is
	interpreted as a text representation of markup, and MUST NOT be
	interpreted as markup itself.
	4. If the value of "type" ends with "+xml" or "/xml", the content of
	atom:content may include child elements, and SHOULD be suitable
	for handling by software that knows the indicated media type. If
	the "src" attribute is not provided, this would normally mean
	that the "atom:content" element would contain a single child
	element which would serve as the root element of the XML document
	of the indicated type.
	5. If the value of "type" begins with "text/" the content of
	atom:content MUST NOT contain child elements.
	6. For all other values of "type", the content of atom:content MUST
	be a valid Base64 encoding [RFC3548], which when decoded SHOULD
	be suitable for handling by software that knows the indicated
	media type. In this case, the characters in the Base64 encoding
	may be preceded and followed in the atom:content element by
	whitespace, and lines are separated by a single newline (U+000A)
	character.
	4.16 The "atom:introspection" Element
	The "atom:introspection" element is a Service construct that conveys
	the URI of an introspection file associated with a feed.
	atomIntrospection =		The "atom:title" element is a Text construct that conveys a
	element atom:introspection { atomServiceConstruct }		human-readable title for an entry or feed.
	4.17 The "atom:post" Element		atomTitle = element atom:title { atomTextConstruct }
	The "atom:post" element is a Service construct that conveys the URI		4.2.15 The "atom:updated" Element
	used to add entries to a feed.
	atomPost = element atom:post { atomServiceConstruct }		The "atom:updated" element is a Date construct indicating the most
			recent instant in time when an entry or feed was modified in a way
			the publisher considers significant. Therefore, not all
			modifications necessarily result in a changed atom:updated value.
	4.18 The "atom:edit" Element		atomUpdated = element atom:updated { atomDateConstruct }
	The "atom:edit" element is a Service construct that conveys the URI		Publishers MAY change the value of this element over time.
	used to retrieve and edit the source representation of an entry.
	atomEdit = element atom:edit { atomServiceConstruct }		5. Securing Atom Documents
	4.19 The "atom:tagline" Element		Because Atom is an XML-based format, existing XML security mechanisms
			can be used to secure its content.
	The "atom:tagline" element is a Text construct that conveys a		5.1 Digital Signatures
	human-readable description or tagline for the feed.
	atomTagline = element atom:tagline { atomTextConstruct }		The root of an Atom document (i.e., atom:feed in an Atom Feed
			Document, atom:entry in an Atom Entry Document) MAY have an Enveloped
			Signature, as described by XML-Signature and Syntax Processing
			[W3C.REC-xmldsig-core-20020212].
	4.20 The "atom:generator" Element		Processors MUST NOT reject an Atom Document containing such a
			signature because they are not capable of verifying it; they MUST
			continue processing and MAY inform the user of their failure to
			validate the signature.
	The "atom:generator" element's content identifies the software agent		In other words, the presence of an element with the namespace IRI
	used to generate a feed, for debugging and other purposes.		"http://www.w3.org/2000/09/xmldsig#" and a local name of "Signature"
			as a child of the document element must not cause an Atom Processor
			to fail merely because of its presence.
	atomGenerator = element atom:generator {		Other elements in an Atom Document MUST NOT be signed unless their
	atomCommonAttributes,		definitions explicitly specify such a capability.
	attribute url { atomUri }?,
	attribute version { text }?,
	text
	}
	The content of this element, when present, MUST be a string that is a		5.2 Encryption
	human-readable name for the generating agent.
	The atom:generator element MAY have a "uri" attribute whose value		The root of an Atom Document (i.e., atom:feed in an Atom Feed
	MUST be a URI reference [RFC3986]. When dereferenced, that URI		Document, atom:entry in an Atom Entry Document) MAY be encrypted,
	SHOULD produce a representation that is relevant to that agent.		using the mechanisms described by XML Encryption Syntax and
			Processing [W3C.REC-xmlenc-core-20021210].
	The atom:generator element MAY have a "version" attribute that		6. Extending Atom
	indicates the version of the generating agent. When present, its
	value is unstructured text.
	4.21 The "atom:info" Element		6.1 Extensions From Non-Atom Vocabularies
	The "atom:info" element is a Text construct that conveys a		This specification describes Atom's XML markup vocabulary. Markup
	human-readable explanation of the feed format itself. The atom:info		from other vocabularies ("foreign markup") can be used in an Atom
	element SHOULD NOT be considered meaningful by processors; it is a		document. Note that the atom:content element is designed to support
	convenience to publishers.		the inclusion of arbitrary foreign markup.
	atomInfo = element atom:info { atomTextConstruct }		6.2 Extensions To the Atom Vocabulary
	5. Managing Feed State		Future versions of this specification may add new elements and
			attributes to the Atom markup vocabulary. Software written to
			conform to this version of the specification will not be able to
			process such markup correctly and, in fact, will not be able to
			distinguish it from markup error. For the purposes of this
			discussion, unrecognized markup from the Atom vocabulary will be
			considered "foreign "markup".
	[[ talk about what it means to keep a view of a feed ]]		Unlike markup from other vocabularies, foreign markup from the Atom
			vocabulary MAY appear at any location in an Atom document.
	6. Securing Atom Documents		6.3 Software Processing of Foreign Markup
	Because Atom is an XML-based format, existing XML security mechanisms		Software processing an Atom Document which encounters foreign markup
	can be used to secure its content.		in a location that is legal according to this specification MUST NOT
			stop processing or signal an error. It may be the case that the
			software is able to process the foreign markup correctly and does so.
			Otherwise, such markup is termed "unknown foreign markup".
	6.1 Digital Signatures		When unknown foreign markup is encountered as a child of atom:entry,
			atom:feed, or a Person Construct, software MAY [[anchor67: Changed to
			MAY from SHOULD. Republishers might want to copy it. --R. Sayre]]
			bypass the markup and any textual content and MUST NOT change its
			behavior as a result of the markup's presence.
	The document element of an Atom document (i.e., atom:feed in an Atom		When unknown foreign markup is encountered in a Text Contruct or
	Feed Document, atom:entry in an Atom Entry Document) MAY have an		atom:content element, software SHOULD ignore the markup and process
	Enveloped Signature, as described by XML-Signature and Syntax		any text content of foreign elements as though the surrounding markup
	Processing [W3C.REC-xmldsig-core-20020212].		were not present.
	Processors MUST NOT reject an Atom document containing such a		6.4 Extension Elements
	signature because they are not capable of verifying it; they MUST
	continue processing and MAY inform the user of their failure to
	validate the signature.
	In other words, the presence of an element with the namespace URI		Atom allows foreign markup anywhere in an Atom document. Child
	"http://www.w3.org/2000/09/xmldsig#" and a local name of "Signature"		elements of atom:entry and atom:feed are considered "metadata"
	as a child of the document element must not cause a processor to fail		elements, and are described below. Child elements of Person
	merely because of its presence.		Constructs are considered to apply to the construct. The role of
			other foreign markup is undefined by this specification.
	Other elements in an Atom document MUST NOT be signed unless their		6.4.1 Simple Extension Elements
	definitions explicitly specify such a capability.
	6.2 Encryption		A Simple Extension element MUST NOT have any attributes or child
			elements. The element MAY contain either character data, or be
			empty.
	The document element of an Atom document (i.e., atom:feed in an Atom		The element can be interpreted as a simple property (or name/value
	Feed Document, atom:entry in an Atom Entry Document) MAY be		pair) of the parent element that encloses it. The pair consisting of
	encrypted, using the mechanisms described by XML Encryption Syntax		the namespace-URI of the element and the local name of the element
	and Processing [W3C.REC-xmlenc-core-20021210].		can be interpreted as the name of the property. The character data
			content of the element can be interpreted as the value of the
			property. If the element is empty, then the property value can be
			interpreted as an empty string.
	7. Embedding Atom in Other Formats		6.4.2 Structured Extension Elements
	[[ ... ]]		The root element of a Structured Extension element MUST have at least
			one attribute or child element. It MAY have attributes, it MAY
			contain well-formed XML content (including character data), or it MAY
			be empty.
	8. Extending Atom		The structure of a Structured Extension element, including the order
			of its child elements, could be significant.
	[[ ... ]]		This specification does not provide an interpretation of a Structured
			Extension element. The syntax of the XML contained in the element,
			and an interpretation of how the element relates to its containing
			element is defined by the specification of the Atom extension.
	9. IANA Considerations		7. IANA Considerations
	An Atom Document, when serialized as XML 1.0, can be identified with		An Atom Document, when serialized as XML 1.0, can be identified with
	the following media type:		the following media type:
	MIME media type name: application		MIME media type name: application
	MIME subtype name: atom+xml		MIME subtype name: atom+xml
	Mandatory parameters: None.		Mandatory parameters: None.
	Optional parameters:		Optional parameters:
	"charset": This parameter has identical semantics to the charset		"charset": This parameter has identical semantics to the charset
	parameter of the "application/xml" media type as specified in		parameter of the "application/xml" media type as specified in
	RFC 3023 [RFC3023]. [RFC3023].		[RFC3023].
	Encoding considerations: Identical to those of "application/xml" as		Encoding considerations: Identical to those of "application/xml" as
	described in RFC 3023 [RFC3023], section 3.2.		described in [RFC3023], section 3.2.
	Security considerations: As defined in this specification. [[update		Security considerations: As defined in this specification.
	upon publication]]		[[anchor71: update upon publication]]
	In addition, as this media type uses the "+xml" convention, it		In addition, as this media type uses the "+xml" convention, it
	shares the same security considerations as described in RFC 3023		shares the same security considerations as described in [RFC3023],
	[RFC3023], section 10.		section 10.
	Interoperability considerations: There are no known interoperability		Interoperability considerations: There are no known interoperability
	issues.		issues.
	Published specification: This specification. [[update upon		Published specification: This specification. [[anchor72: update upon
	publication]]		publication]]
	Applications which use this media type: No known applications		Applications that use this media type: No known applications
	currently use this media type.		currently use this media type.
	Additional information:		Additional information:
	Magic number(s): As specified for "application/xml" in RFC 3023		Magic number(s): As specified for "application/xml" in [RFC3023],
	[RFC3023], section 3.2.		section 3.2.
	File extension: .atom		File extension: .atom
	Fragment identifiers: As specified for "application/xml" in RFC 3023		Fragment identifiers: As specified for "application/xml" in
	[RFC3023], section 5.		[RFC3023], section 5.
	Base URI: As specified in RFC 3023 [RFC3023], section 6.		Base URI: As specified in [RFC3023], section 6.
	Macintosh File Type code: TEXT		Macintosh File Type code: TEXT
	Person and email address to contact for further information: Mark		Person and email address to contact for further information: Mark
	Nottingham <mnot@pobox.com>		Nottingham <mnot@pobox.com>
	Intended usage: COMMON		Intended usage: COMMON
	Author/Change controller: This specification's author(s). [[update		Author/Change controller: This specification's author(s).
	upon publication]]		[[anchor73: update upon publication]]
	9.1 Registry of Link Relations		7.1 Registry of Link Relations
	This registry is maintained by IANA and initially contains the two		This registry is maintained by IANA and initially contains five
	values: "alternate" and "related". New assignments are subject to		values: "alternate", "related", "self", "enclosure", and "via". New
	IESG Approval, as outlined in [RFC2434]. Requests should be made by		assignments are subject to IESG Approval, as outlined in [RFC2434].
	email to IANA, which will then forward the request to the IESG		Requests should be made by email to IANA, which will then forward the
	requesting approval. The request should contain discussion of at		request to the IESG requesting approval. The request should contain
	least the following five topics:		discussion of at least the following five topics:
	o A value for the "rel" attribute that conforms to the syntax rule		o A value for the "rel" attribute that conforms to the syntax rule
	given in Section 4.6.2		given in Section 4.2.9.2
	o Common name for link type.		o Common name for link type.
	o Description of link type semantics.		o Description of link type semantics.
	o Expected display characteristics.		o Expected display characteristics.
	o Security considerations.		o Security considerations.
	10. Security Considerations		8. Security Considerations
			8.1 HTML and XHTML Content
			Text Constructs and atom:content allow the delivery of HTML and XHTML
			to receiving software, which may process it. Many elements in these
			languages are considered 'unsafe' in that they open clients to one or
			more types of attack. Implementers of software which processes Atom
			should carefully consider their handling of every type of element
			when processing incoming (X)HTML in Atom documents. See the security
			sections of RFC 2854 and HTML 4.01 for guidance.
			Atom Processors should pay particular attention to the security of
			the IMG, SCRIPT, EMBED, OBJECT, FRAME, FRAMESET, IFRAME, META, and
			LINK elements, but other elements may also have negative security
			properties.
			(X)HTML can either directly contain or indirectly reference
			executable content.
			8.2 URIs
			Atom Processors handle URIs. See Section 7 of [RFC3986].
			8.3 IRIs
			Atom Processors handle IRIs. See Section 8 of [RFC3987].
			8.4 Encryption and Signing
	Atom document can be encrypted and signed using		Atom document can be encrypted and signed using
	[W3C.REC-xmlenc-core-20021210] and [W3C.REC-xmldsig-core-20020212],		[W3C.REC-xmlenc-core-20021210] and [W3C.REC-xmldsig-core-20020212],
	respectively, and is subject to the security considerations implied		respectively, and is subject to the security considerations implied
	by their use.		by their use.
	11. References		9. References
	11.1 Normative References		9.1 Normative References
	[Atom-autodiscovery]		[Atom-autodiscovery]
	Pilgrim, M., "Atom Feed Autodiscovery", work-in-progress,		Pilgrim, M., "Atom Feed Autodiscovery", work-in-progress,
	August 2004.		August 2004.
	[Atom-protocol]		[ISO.8601.1988]
	Gregorio, J. and R. Sayre, "The Atom Publishing Protocol",		International Organization for Standardization, "Data
	work-in-progress, July 2004.		elements and interchange formats - Information interchange
			- Representation of dates and times", ISO Standard 8601,
	[RFC0791] Postel, J., "Internet Protocol", STD 5, RFC 791, September		June 1988.
	1981.
	[RFC1035] Mockapetris, P., "Domain names - implementation and
	specification", STD 13, RFC 1035, November 1987.
	[RFC2045] Freed, N. and N. Borenstein, "Multipurpose Internet Mail		[RFC2045] Freed, N. and N. Borenstein, "Multipurpose Internet Mail
	Extensions (MIME) Part One: Format of Internet Message		Extensions (MIME) Part One: Format of Internet Message
	Bodies", RFC 2045, November 1996.		Bodies", RFC 2045, November 1996.
	[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate		[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
	Requirement Levels", BCP 14, RFC 2119, March 1997.		Requirement Levels", BCP 14, RFC 2119, March 1997.
	[RFC2460] Deering, S. and R. Hinden, "Internet Protocol, Version 6
	(IPv6) Specification", RFC 2460, December 1998.
	[RFC2822] Resnick, P., "Internet Message Format", RFC 2822, April		[RFC2822] Resnick, P., "Internet Message Format", RFC 2822, April
	2001.		2001.
	[RFC3023] Murata, M., St. Laurent, S. and D. Kohn, "XML Media		[RFC3023] Murata, M., St. Laurent, S. and D. Kohn, "XML Media
	Types", RFC 3023, January 2001.		Types", RFC 3023, January 2001.
	[RFC3066] Alvestrand, H., "Tags for the Identification of		[RFC3066] Alvestrand, H., "Tags for the Identification of
	Languages", BCP 47, RFC 3066, January 2001.		Languages", BCP 47, RFC 3066, January 2001.
	[RFC3339] Klyne, G. and C. Newman, "Date and Time on the Internet:		[RFC3339] Klyne, G. and C. Newman, "Date and Time on the Internet:
	Timestamps", RFC 3339, July 2002.		Timestamps", RFC 3339, July 2002.
	[RFC3548] Josefsson, S., "The Base16, Base32, and Base64 Data		[RFC3548] Josefsson, S., "The Base16, Base32, and Base64 Data
	Encodings", RFC 3548, July 2003.		Encodings", RFC 3548, July 2003.
	[RFC3986] Berners-Lee, T., Fielding, R. and L. Masinter, "Uniform		[RFC3986] Berners-Lee, T., Fielding, R. and L. Masinter, "Uniform
	Resource Identifier (URI): Generic Syntax", STD 66, RFC		Resource Identifier (URI): Generic Syntax", STD 66,
	3986, January 2005.		RFC 3986, January 2005.
			[RFC3987] Duerst, M. and M. Suignard, "Internationalized Resource
			Identifiers (IRIs)", RFC 3987, January 2005.
	[W3C.NOTE-datetime-19980827]		[W3C.NOTE-datetime-19980827]
	Wolf, M. and C. Wicksteed, "Date and Time Formats", W3C		Wolf, M. and C. Wicksteed, "Date and Time Formats", W3C
	NOTE NOTE-datetime-19980827, August 1998.		NOTE NOTE-datetime-19980827, August 1998.
			[W3C.REC-html401-19991224]
			Raggett, D., Hors, A. and I. Jacobs, "HTML 4.01
			Specification", W3C REC REC-html401-19991224, December
			1999.
			[W3C.REC-xhtml-basic-20001219]
			Baker, M., Ishikawa, M., Matsui, S., Stark, P., Wugofski,
			T. and T. Yamakami, "XHTML Basic", W3C
			REC REC-xhtml-basic-20001219, December 2000.
	[W3C.REC-xml-20040204]		[W3C.REC-xml-20040204]
	Yergeau, F., Paoli, J., Sperberg-McQueen, C., Bray, T. and		Yergeau, F., Paoli, J., Sperberg-McQueen, C., Bray, T. and
	E. Maler, "Extensible Markup Language (XML) 1.0 (Third		E. Maler, "Extensible Markup Language (XML) 1.0 (Third
	Edition)", W3C REC REC-xml-20040204, February 2004.		Edition)", W3C REC REC-xml-20040204, February 2004.
	[W3C.REC-xml-infoset-20011024]		[W3C.REC-xml-infoset-20040204]
	Tobin, R. and J. Cowan, "XML Information Set", W3C		Cowan, J. and R. Tobin, "XML Information Set (Second
	FirstEdition REC-xml-infoset-20011024, October 2001.		Edition)", W3C REC REC-xml-infoset-20040204, February
			2004.
	[W3C.REC-xml-names-19990114]		[W3C.REC-xml-names-19990114]
	Hollander, D., Bray, T. and A. Layman, "Namespaces in		Hollander, D., Bray, T. and A. Layman, "Namespaces in
	XML", W3C REC REC-xml-names-19990114, January 1999.		XML", W3C REC REC-xml-names-19990114, January 1999.
	[W3C.REC-xmlbase-20010627]		[W3C.REC-xmlbase-20010627]
	Marsh, J., "XML Base", W3C REC REC-xmlbase-20010627, June		Marsh, J., "XML Base", W3C REC REC-xmlbase-20010627, June
	2001.		2001.
	[W3C.REC-xmldsig-core-20020212]		[W3C.REC-xmldsig-core-20020212]
	Solo, D., Reagle, J. and D. Eastlake, "XML-Signature		Solo, D., Reagle, J. and D. Eastlake, "XML-Signature
	Syntax and Processing", W3C REC REC-xmldsig-core-20020212,		Syntax and Processing", W3C REC REC-xmldsig-core-20020212,
	February 2002.		February 2002.
	[W3C.REC-xmlenc-core-20021210]		[W3C.REC-xmlenc-core-20021210]
	Reagle, J. and D. Eastlake, "XML Encryption Syntax and		Reagle, J. and D. Eastlake, "XML Encryption Syntax and
	Processing", W3C REC REC-xmlenc-core-20021210, December		Processing", W3C REC REC-xmlenc-core-20021210, December
	2002.		2002.
	11.2 Informative References		[W3C.REC-xmlschema-2-20041028]
			Malhotra, A. and P. Biron, "XML Schema Part 2: Datatypes
			Second Edition", W3C REC REC-xmlschema-2-20041028, October
			2004.
			9.2 Informative References
	[RELAX-NG]		[RELAX-NG]
	OASIS Technical Committee: RELAX NG, "RELAX NG		OASIS Technical Committee: RELAX NG, "RELAX NG
	Specification", December 2001.		Specification", December 2001.
	[RFC2434] Narten, T. and H. Alvestrand, "Guidelines for Writing an		[RFC2434] Narten, T. and H. Alvestrand, "Guidelines for Writing an
	IANA Considerations Section in RFCs", BCP 26, RFC 2434,		IANA Considerations Section in RFCs", BCP 26, RFC 2434,
	October 1998.		October 1998.
	URIs
	[1] <http://www.imc.org/atom-syntax/index.html>
	[2] <http://www.intertwingly.net/wiki/pie/FrontPage>
	Authors' Addresses		Authors' Addresses
	Mark Nottingham (editor)		Mark Nottingham (editor)
	EMail: mnot@pobox.com		Email: mnot@pobox.com
	URI: http://www.mnot.net/		URI: http://www.mnot.net/
	Robert Sayre (editor)		Robert Sayre (editor)
	Boswijck Memex Consulting		Boswijck Memex Consulting
	EMail: rfsayre@boswijck.com		Email: rfsayre@boswijck.com
	URI: http://boswijck.com		URI: http://boswijck.com
	Appendix A. Contributors		Appendix A. Contributors
	The following people contributed to preliminary drafts of this		The following people contributed to preliminary drafts of this
	document: Tim Bray, Mark Pilgrim, and Sam Ruby. Norman Walsh		document: Tim Bray, Mark Pilgrim, and Sam Ruby. Norman Walsh
	provided the Relax NG schema. The content and concepts within are a		provided the Relax NG schema. The content and concepts within are a
	product of the Atom community and the Atom Publishing Format and		product of the Atom community and the Atom Publishing Format and
	Protocol Working Group.		Protocol Working Group.
	Appendix B. Collected RELAX NG Compact Schema		Appendix B. Collected RELAX NG Compact Schema
	This appendix is informative.		This appendix is informative.
	# -*- Relax NG -*-		# -*- Relax NG -*-
	namespace local = ""		namespace local = ""
	namespace atom =
	"http://purl.org/atom/ns#draft-ietf-atompub-format-04"		namespace
			atom = "http://purl.org/atom/ns#draft-ietf-atompub-format-06"
	namespace s = "http://www.ascc.net/xml/schematron"		namespace s = "http://www.ascc.net/xml/schematron"
	start = atomFeed | atomEntry		start = atomFeed | atomEntry
	# Attribute definitions		## Attribute definitions
	atomCommonAttributes =		atomCommonAttributes =
	attribute xml:base { atomUri }?,		attribute xml:base { atomUri }?,
	attribute xml:lang { atomLanguageTag }?		attribute xml:lang { atomLanguageTag }?
	atomVersionAttribute =		## Common Atom Constructs
	attribute version {"draft-ietf-atompub-format-05 : do not deploy"}
	# Common Atom Constructs
	atomPlainTextConstruct =		atomPlainTextConstruct =
	atomCommonAttributes,		atomCommonAttributes,
	attribute type { "TEXT" | "HTML" }?,		attribute type { "TEXT" | "HTML" }?,
	text		text
	atomXHTMLTextConstruct =		atomXHTMLTextConstruct =
	atomCommonAttributes,		atomCommonAttributes,
	attribute type { "XHTML" },		attribute type { "XHTML" },
	(text|anyElement)*		(text|anyElement)*
	atomTextConstruct = atomPlainTextConstruct | atomXHTMLTextConstruct		atomTextConstruct =
			atomPlainTextConstruct | atomXHTMLTextConstruct
	atomPersonConstruct =		atomPersonConstruct =
	atomCommonAttributes,		atomCommonAttributes,
	(element atom:name { text }		(element atom:name { text }
	& element atom:uri { atomUri }?		& element atom:uri { atomUri }?
	& element atom:email { atomEmailAddress }?)		& element atom:email { atomEmailAddress }?)
	atomDateConstruct =		atomDateConstruct =
	atomCommonAttributes,		atomCommonAttributes,
	xsd:dateTime		xsd:dateTime
			## Container elements
	atomServiceConstruct =
	atomCommonAttributes,
	attribute href { atomUri }
	atomIdentityConstruct =
	atomCommonAttributes,
	(atomUri)
	# atom:feed		# atom:feed
	# TODO: Test for multiple atom:link/@rel='alternate' with		# TODO: Test for multiple atom:link/@rel='alternate' with
	# the same @type The following tests are simple to do,		# the same @type The following tests are simple to do,
	# but my validator is giving me trouble.		# but my validator is giving me trouble.
	# TODO: Debug and add them back		# TODO: Debug and add them back
	# Test for at least one atom:link/@rel='alternate'		# Test for at least one atom:link/@rel='alternate'
	# Test for atom:author or all atom:entry have atom:author		# Test for atom:author or all atom:entry have atom:author
	# atom:feed		# atom:feed
	atomFeed =		atomFeed =
	element atom:feed {
	atomCommonAttributes,
	atomVersionAttribute,
	(atomHead
	& atomEntry*
	& anyElement*)
	}
	# atom:head
	atomHead =
	[		[
	s:rule [		s:rule [
	context = "atom:head"		context = "atom:feed"
	s:assert [		s:assert [
	test = "atom:link[@rel='alternate']"		test = "atom:link[@rel='alternate']"
	"An atom:feed must have at least one link element		"An atom:feed must have at least one link element
	with a rel attribute of 'alternate'."		with a rel attribute of 'alternate'."
	]		]
	]		]
	s:rule [		s:rule [
	context = "atom:head"		context = "atom:feed"
	s:assert [		s:assert [
	test = "atom:author or not(../atom:entry[count(atom:author) = 0])"		test = "atom:author or not(../atom:entry[count(atom:author) = 0])"
	"An atom:feed must have an atom:author unless all of		"An atom:feed must have an atom:author unless all of
	its atom:entry children have an atom:author."		its atom:entry children have an atom:author."
	]		]
	]		]
	]		]
	element atom:head {
			element atom:feed {
	atomCommonAttributes,		atomCommonAttributes,
	(atomTitle		(atomAuthor?
	& atomUpdated		& atomCategory*
	& atomLink+
	& atomId?
	& atomAuthor?
	& atomContributor*		& atomContributor*
	& atomTagline?
	& atomGenerator?
	& atomInfo?
	& atomCopyright?		& atomCopyright?
	& atomCategory*		& atomGenerator?
	& atomIntrospection?		& atomIcon?
	& atomPost?		& atomId?
	& anyElement*)		& atomImage?
			& atomLink+
			& atomSubtitle?
			& atomTitle
			& atomUpdated
			& anyElement* ),
			atomEntry*
	}		}
	# atom:entry		# atom:entry
	# TODO: Test for multiple atom:link @rel='alternate'		# TODO: Test for multiple atom:link @rel='alternate'
	# with the same @type		# with the same @type
	# TODO: Test for required atom:summary		# TODO: Test for required atom:summary
	atomEntry =		atomEntry =
	[		[
	s:rule [		s:rule [
	context = "/atom:entry"
	s:assert [
	test = "@version"
	"The version attribute is required on standalone
	atom:entry elements."
	]
	]
	s:rule [
	context = "atom:entry"		context = "atom:entry"
	s:assert [		s:assert [
	test = "atom:link[@rel='alternate']"		test = "atom:link[@rel='alternate']"
	"An atom:entry must have at least one link element		"An atom:entry must have at least one link element
	with a rel attribute of 'alternate'."		with a rel attribute of 'alternate'."
	]		]
	]		]
	s:rule [		s:rule [
	context = "atom:entry"		context = "atom:entry"
	s:assert [		s:assert [
	skipping to change at page 41, line 4		skipping to change at page 40, line 29
	]		]
	]		]
	s:rule [		s:rule [
	context = "atom:entry"		context = "atom:entry"
	s:assert [		s:assert [
	test = "atom:author or ../atom:author"		test = "atom:author or ../atom:author"
	"An atom:entry must have an atom:author		"An atom:entry must have an atom:author
	if the parent atom:feed does not."		if the parent atom:feed does not."
	]		]
	]		]
	]		]
	element atom:entry {		element atom:entry {
	atomCommonAttributes,		atomCommonAttributes,
	atomVersionAttribute?,		(atomAuthor?
	(atomTitle		& atomCategory*
			& atomContent?
			& atomContributor*
			& atomCopyright?
	& atomId		& atomId
	& atomLink*		& atomLink*
	& atomUpdated
	& atomPublished?		& atomPublished?
	& atomAuthor?		& atomSourceFeed?
	& atomContributor*
	& atomHost?
	& atomCopyright?
	& atomCategory*
	& atomEdit?
	& atomSummary?		& atomSummary?
	& atomContent?		& atomTitle
	& atomHead?		& atomUpdated &
	& anyElement*)		anyElement*)
	}		}
			# atom:content
	# atom:title		atomInlineTextContent =
			element atom:content {
	atomTitle = element atom:title { atomTextConstruct }		atomCommonAttributes,
			attribute type { "text | "html" | atomMediaType }?,
	# atom:id		(text)*
			}
	atomId = element atom:id { atomIdentityConstruct }		atomInlineXHTMLContent =
			element atom:content {
			atomCommonAttributes,
			attribute type { "xhtml" | atomMediaType }?,
			(text|anyElement)*
			}
	atomLink = element atom:link {		atomOutOfLineContent =
			element atom:content {
	atomCommonAttributes,		atomCommonAttributes,
	attribute href { atomUri },		attribute type { "text" | "html" | "xhtml" | atomMediaType }?,
	attribute rel { atomNCName | atomUri }?,		attribute src { atomUri },
	attribute type { atomMediaType }?,
	attribute hreflang { atomLanguageTag }?,
	attribute title { text }?,
	attribute length { text }?,
	empty		empty
	}		}
	# atom:updated		atomContent = atomInlineTextContent
	# TODO: Test for a timezone that SHOULD be UTC		| atomInlineXHTMLContent
			| atomOutOfLineContent
	atomUpdated = element atom:updated { atomDateConstruct }
	# atom:published		## Metadata Elements
	atomPublished = element atom:published { atomDateConstruct }
	# atom:author		# atom:author
	atomAuthor = element atom:author { atomPersonConstruct }		atomAuthor = element atom:author { atomPersonConstruct }
	# atom:contributor
	atomContributor = element atom:contributor { atomPersonConstruct }
	# atom:host
	# TODO: tighten this up
	atomHost = element atom:host { text }
	# atom:copyright
	atomCopyright = element atom:copyright { atomTextConstruct }
	# atom:category		# atom:category
	atomCategory = element atom:category {		atomCategory = element atom:category {
	atomCommonAttributes,		atomCommonAttributes,
	attribute term { text },		attribute term { text },
	attribute scheme { atomUri }?,		attribute scheme { atomUri }?,
	attribute label { text }?,		attribute label { text }?,
	empty		empty
	}		}
	# atom:summary		# atom:contributor
			atomContributor = element atom:contributor { atomPersonConstruct }
	atomSummary = element atom:summary { atomTextConstruct }		# atom:copyright
	# atom:content		atomCopyright = element atom:copyright { atomTextConstruct }
	atomInlineTextContent =		# atom:generator
	element atom:content {
	atomCommonAttributes,
	attribute type { "TEXT" | "HTML" | atomMediaType }?,
	(text)*
	}
	atomInlineXHTMLContent =		atomGenerator = element atom:generator {
	element atom:content {
	atomCommonAttributes,		atomCommonAttributes,
	attribute type { "XHTML" | atomMediaType }?,		attribute uri { atomUri }?,
	(text|anyElement)*		attribute version { text }?,
			text
	}		}
	atomOutOfLineContent =
	element atom:content {		# atom:icon
			atomIcon = element atom:icon { atomCommonAttributes, (atomUri) }
			# atom:id
			atomId = element atom:id { }
			# atom:image
			atomImage = element atom:image { atomCommonAttributes, (atomUri) }
			# atom:link
			atomLink = element atom:link {
	atomCommonAttributes,		atomCommonAttributes,
	attribute type { "TEXT" | "HTML" | "XHTML" | atomMediaType }?,		attribute href { atomUri },
	attribute src { atomUri },		attribute rel { atomNCName | atomUri }?,
			attribute type { atomMediaType }?,
			attribute hreflang { atomLanguageTag }?,
			attribute title { text }?,
			attribute length { text }?,
	empty		empty
	}		}
	atomContent = atomInlineTextContent		# atom:published
	| atomInlineXHTMLContent
	| atomOutOfLineContent
	# atom:introspection		atomPublished = element atom:published { atomDateConstruct }
	atomIntrospection =		# atom:source-feed
	element atom:introspection { atomServiceConstruct }
	# atom:post		atomSourceFeed =
			element atom:source-feed {
			atomCommonAttributes,
			( atomTitle
			& atomUpdated
			& atomLink+
			& atomIcon
			& atomId?
			& atomImage?
			& atomSubtitle?
			& atomAuthor?
			& atomContributor*
			& atomCopyright?
			& atomCategory*
			& atomGenerator?
			& anyElement* )
			}
	atomPost = element atom:post { atomServiceConstruct }		# atom:subtitle
	# atom:edit		atomSubtitle = element atom:subtitle { atomTextConstruct }
	atomEdit = element atom:edit { atomServiceConstruct }		# atom:summary
	# atom:tagline		atomSummary = element atom:summary { atomTextConstruct }
	atomTagline = element atom:tagline { atomTextConstruct }		# atom:title
	# atom:generator		atomTitle = element atom:title { atomTextConstruct }
	atomGenerator = element atom:generator {		# atom:updated
	atomCommonAttributes,		# TODO: Test for a timezone that SHOULD be UTC
	attribute url { atomUri }?,
	attribute version { text }?,
	text
	}
	# atom:info		atomUpdated = element atom:updated { atomDateConstruct }
	atomInfo = element atom:info { atomTextConstruct }
	# Low-level simple types		# Low-level simple types
	# TODO: can anything more specific be said about these types?		# TODO: can anything more specific be said about these types?
	atomNCName = xsd:string { minLength = "1" pattern = "[^:]*" }		atomNCName = xsd:string { minLength = "1" pattern = "[^:]*" }
	atomMediaType = text		atomMediaType = text
	atomLanguageTag = text		atomLanguageTag = text
	atomUri = text		atomUri = text
	atomEmailAddress = text		atomEmailAddress = text
	skipping to change at page 45, line 5		skipping to change at page 45, line 5
	anyElement =		anyElement =
	element * - atom:*		element * - atom:*
	{		{
	(attribute * { text }		(attribute * { text }
	| text		| text
	| anyElement)*		| anyElement)*
	}		}
	# EOF		# EOF
	Appendix C. Revision History		Appendix C. Change Log
	[[ this section should be removed before final publication. ]]		[[anchor85: This section should be removed before final
			publication.]]
			-06: Move Identity Construct into atom:id (only place it's used)
			atom:id values must be unique within a feed.
			restore atom:copyright definition mistakenly dropped during
			alphabetizing.
			Remove atom:head, add atom:source-feed, and "Extension Construct"
			text in an effort to accurately reflect WG consensus on data model
			and extensibility, acknowledging two opinions in favor of
			atom:head.
			Note @hreflang issue.
			Add comment on atom:entry/atom:summary requirements.
			Rework atom:id text. The dereferencing section didn't talk about
			dereferencing.
			Remove protocol reference.
			Alphabetize where appropriate (PaceOrderSpecAlphabetically).
			Add mI language (PaceExtendingAtom).
			Add atom:icon and atom:image (PaceImageAndIcon).
			Change atom:tagline to atom:subtitle
			Add inline XHTML language (PaceXHTMLNamespaceDiv).
			Change "TEXT" etc, to lowercase
			Change example id IRI to urn:uuid:...
			Add rel="self" (PaceFeedLink).
			Add Feed State text (PaceNoFeedState).
			Move to IRIs (PaceIRI).
			Add rel="via" (PaceLinkRelVia).
			Add rel="enclosure" (PaceEnclosuresAndPix).
			Remove info and host (PaceRemoveInfoAndHost)
			Clarify order of entries (PaceEntryOrder).
			Remove version attribute (PaceRemoveVersionAttr).
			Date format roundup (PaceDatesXSD).
			Remove Service construct and elements.
			fix atom:contributor cardinality typo
			Removed motivation/design principles note; if we haven't come up
			with them by now...
			Put conformance text into notational conventions.
			Removed instances of 'software'; too specific.
			Added refs to HTML and XHTML.
			Updated ref to Infoset.
			Various editorial tweaks.
			Fix RFC 3023 refs in IANA section
			Adjust head/link requirement
			fix @version typos
	-05: Add RNC from N. Walsh.		-05: Add RNC from N. Walsh.
	Re-organize element definitions.		Re-organize element definitions.
	Lift the prohibition on other types of DSig and encryption.		Lift the prohibition on other types of DSig and encryption.
	Remove text on "indiscriminate use" of DSig and XMLEnc.		Remove text on "indiscriminate use" of DSig and XMLEnc.
	-04: Update URI terms for 2396bis.		-04: Update URI terms for 2396bis.
	Add Category construct (PaceCategoryRevised).		Add Category construct (PaceCategoryRevised).
	Insert paranoid XHTML interpretation guidelines.		Insert paranoid XHTML interpretation guidelines.
	Adjust atom:copyright, per chairs' instruction.		Adjust atom:copyright, per chairs' instruction.
	Add atom:host as child element of atom:entry, per chairs'		Add atom:host as child element of atom:entry, per chairs'
	direction (PacePersonConstruct).		direction (PacePersonConstruct).
End of changes.
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