<?xml version="1.0" encoding="UTF-8"?><?xml-stylesheet href="http://www.w3.org/StyleSheets/TR/base.css" type="text/css"?><!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN""http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd"><html xmlns="http://www.w3.org/1999/xhtml" lang="en" xml:lang="en"><head><meta name="generator" content="HTML Tidy, see www.w3.org" /><title>RDFa in XHTML: Syntax and Processing</title><style type="text/css">code { font-family: monospace; }span.hilite { color: red; font-weight: bold }div.constraint,div.issue,div.note,div.notice { margin-left: 2em; }dt.label { display: run-in; }li p { margin-top: 0.3em; margin-bottom: 0.3em; }div.example pre { margin-left: 1em; margin-top: 0em; margin-bottom: 0em}div.example { background-color: #d5dee3; border-top-width: 4px; border-top-style: double; border-top-color: #d3d3d3; border-bottom-width: 4px; border-bottom-style: double; border-bottom-color: #d3d3d3; padding: 4px; margin: 0em }div.explanation { background-color: lightblue; width: 60%; margin: 12px; padding: 8px; }div.explanation li { margin-top: 8px; }div.explanation dd { margin: 4px; }.xmlverb-default { color: #333333; background-color: #ffffff; font-family: monospace }.xmlverb-element-name { color: #990000 }.xmlverb-element-nsprefix { color: #666600 }.xmlverb-attr-name { color: #660000 }.xmlverb-attr-content { color: #000099; font-weight: bold }.xmlverb-ns-name { color: #666600 }.xmlverb-ns-uri { color: #330099 }.xmlverb-text { color: #000000; font-weight: bold }.xmlverb-comment { color: #006600; font-style: italic }.xmlverb-pi-name { color: #006600; font-style: italic }.xmlverb-pi-content { color: #006666; font-style: italic }p.issueTitle { font-size: 150% ;}div.issue { background-color: #cfc ; border: none ; margin-right: 5% ;}</style><link rel="stylesheet" type="text/css" href="http://www.w3.org/StyleSheets/TR/base.css" /></head><body><div class="head"><a href="http://www.w3.org/"><img src="http://www.w3.org/Icons/w3c_home" alt="W3C" height="48" width="72" /></a> <h1><a id="title" name="title"> RDFa in XHTML: Syntax</a></h1><h2><a id="subtitle" name="subtitle"> A collection of attributes and processing rules for extending XHTML to support RDF</a></h2><h2><a id="w3c-doctype" name="w3c-doctype"> W3C Editor's Draft 18 September 2007</a></h2><dl><dt>This version:</dt><dd><a href="http://www.w3.org/MarkUp/2007/ED-rdfa-syntax-20070918">http://www.w3.org/MarkUp/2007/ED-rdfa-syntax-20070918</a></dd><dt>Latest version:</dt><dd><a href="http://www.w3.org/TR/rdfa-syntax">http://www.w3.org/TR/rdfa-syntax</a></dd><dt>Previous Editor's Draft:</dt><dd><a id='previousDraft' href='http://www.w3.org/MarkUp/2007/ED-rdfa-syntax-20070912'>http://www.w3.org/MarkUp/2007/ED-rdfa-syntax-20070912</a></dd><dt>Diff from previous Editor's Draft:</dt><dd><a href="rdfa-syntax-diff.html">rdfa-syntax-diff.html</a></dd><dt>Editors:</dt><dd>Ben Adida, Creative Commons <a href="mailto:ben@adida.net"> ben@adida.net</a></dd><dd>Mark Birbeck, <a href="http://www.formsPlayer.com/">x-port.net Ltd.</a> <a href="mailto:mark.birbeck@x-port.net">mark.birbeck@x-port.net</a></dd><dd>Shane McCarron, <a href="http://www.aptest.com">Applied Testing and Technology, <abbr title="Incorporated">Inc.</abbr></a> <a href="mailto:shane@aptest.com">shane@aptest.com</a></dd><dd>Steven Pemberton, CWI</dd></dl><p>This document is also available in these non-normative formats: <a href="rdfa-syntax.ps">PostScript version</a>, <a href="rdfa-syntax.pdf">PDF version</a>, <a href="rdfa-syntax.zip">ZIParchive</a>, and <a href="rdfa-syntax.tgz">Gzip'd TAR archive</a>.</p><p>The English version of this specification is the only normative version. Non-normative <a href="http://www.w3.org/Consortium/Translation/">translations</a> may also be available.</p><p class="copyright"><a href="http://www.w3.org/Consortium/Legal/ipr-notice#Copyright">Copyright</a> © 2007 <a href="http://www.w3.org/"><acronym title="World Wide Web Consortium">W3C</acronym></a><sup>®</sup> (<a href="http://www.csail.mit.edu/"><acronym title="Massachusetts Institute of Technology">MIT</acronym></a>, <a href="http://www.ercim.org/"><acronym title= "European Research Consortium for Informatics and Mathematics">ERCIM</acronym></a>, <a href="http://www.keio.ac.jp/">Keio</a>), All Rights Reserved. W3C <a href= "http://www.w3.org/Consortium/Legal/ipr-notice#Legal_Disclaimer">liability</a>, <a href="http://www.w3.org/Consortium/Legal/ipr-notice#W3C_Trademarks">trademark</a> and <a href= "http://www.w3.org/Consortium/Legal/copyright-documents">document use</a> rules apply.</p></div><hr /><h2><a id="abstract" name="abstract"> Abstract</a></h2><p>The modern Web is made up of an enormous number of documents that have been created using HTML. These documents contain significant amounts of structured data, which is largely unavailable totools and applications. When publishers can express this data more completely, and when tools can read it, a new world of user functionality becomes available, letting users transfer structured databetween applications and web sites, and allowing browsing applications to improve the user experience: an event on a web page can be directly imported into a user's desktop calendar; a license on adocument can be detected so that users can be informed of their rights automatically; a photo's creator, camera setting information, resolution, location and topic can be published as easily as theoriginal photo itself, enabling structured search and sharing.</p><p>RDFa is a syntax for expressing this structured data in XHTML. The rendered, hypertext data of XHTML is reused by the RDFa markup, so that publishers don't repeat themselves. The underlyingabstract representation is RDF [<a class="nref" href="#ref_RDF-PRIMER">RDF-PRIMER</a>], which lets publishers build their own vocabulary, extend others, and evolve their vocabulary with maximalinteroperability over time. The expressed structure is closely tied to the data, so that rendered data can be copied and pasted along with its relevant structure.</p><p>The rules for interpreting the data are generic, so that there is no need for different rules for different formats; this allows authors and publishers of data to define their own formats withouthaving to update software, register formats via a central authority, or worry that two formats may interfere with each other.</p><p>This document is a detailed syntax specification for RDFa, aimed at:</p><ul><li>those looking to create an RDFa parser, and who therefore need a detailed description of the parsing rules;</li><li>those looking to recommend the use of RDFa within their organisation, and who would like to create some guidelines for their users;</li><li>anyone familiar with RDF, and who wants to understand more about what is happening 'under the hood', when an RDFa parser runs.</li></ul>For those looking for an introduction to the use of RDFa and some real-world examples, please consult the <a href="http://www.w3.org/2006/07/SWD/RDFa/primer">RDFa Primer</a>.<br /><br /><h3><a id="sec_" name="sec_"> How to Read this Document</a></h3><p>If you are already familiar with RDFa, and you want to examine the processing rules—perhaps to create a parser—then you'll find the <a href="#s_model">Processing Model</a> section ofmost interest. It contains an overview of each of the processing steps, followed by more detailed sections, one for each rule.</p><p>If you are not familiar with RDFa, but you <em>are</em> familiar with RDF, then you might find reading the <a href="#s_Syntax_overview">Syntax Overview</a> useful, before looking at the <a href= "#s_model">Processing Model</a> since it gives a range of examples of XHTML mark-up that use RDFa. Seeing some examples first should make reading the processing rules easier.</p><p>If you are not familiar with RDF, then you might want to take a look at the section on <a href="#s_rdfterminology">RDF Terminology</a> before trying to do too much with RDFa. Although RDFa isdesigned to be easy to author—and authors don't need to understand RDF to use it—anyone writing applications that <em>consume</em> RDFa will need to understand RDF. There is a lot ofmaterial on RDF on the web, and a growing range of tools that will support RDFa, so all we try to do in this document is provide enough background on RDF to make the goals of RDFa clearer.</p><p>And finally, if you are not familiar with either RDFa <em>or</em> RDF, and simply want to add RDFa to your documents, then you may find the RDFa Primer [<a class="nref" href="#ref_RDFaPRIMER">RDFaPRIMER</a>] to be a better introduction.</p><h2><a id="status" name="status"> Status of this Document</a></h2><p><em>This section describes the status of this document at the time of its publication. Other documents may supersede this document. A list of current W3C publications and the latest revision ofthis technical report can be found in the <a href="http://www.w3.org/TR/">W3C technical reports index</a> at http://www.w3.org/TR/.</em></p><p>This is an internal draft produced jointly by the Semantic Web Deployment Working Group <a href="#SWD-WG">[SWD-WG]</a> and the XHTML 2 Working Group <a href="#XHTML2-WG">[XHTML2-WG]</a>. Initialwork on RDFa began in the XHTML 2 Working Group <a href="#XHTML2-WG">[XHTML2-WG]</a>.</p><p>This document has no official standing within the W3C. It is also a work in progress, which means it may change at any time, without warning, and you shouldn't rely on anything in thisdocument.</p><h1><a id="contents" name="contents"> Table of Contents</a></h1><div class="toc"><ul class='toc'><li class='tocline'>1. <a href="#s_motivation" class="tocxref">Motivation</a></li><li class='tocline'>2. <a href="#s_Syntax_overview" class="tocxref">Syntax Overview</a> <ul class="toc"><li class='tocline'>2.1. <a href="#sec_2.1." class="tocxref">The RDFa Attributes</a></li><li class='tocline'>2.2. <a href="#sec_2.2." class="tocxref">Examples</a></li></ul></li><li class='tocline'>3. <a href="#s_rdfterminology" class="tocxref">RDF Terminology</a> <ul class="toc"><li class='tocline'>3.1. <a href="#sec_3.1." class="tocxref">Statements</a></li><li class='tocline'>3.2. <a href="#sec_3.2." class="tocxref">Triples</a></li><li class='tocline'>3.3. <a href="#sec_3.3." class="tocxref">URI references</a></li><li class='tocline'>3.4. <a href="#sec_3.4." class="tocxref">Plain literals</a></li><li class='tocline'>3.5. <a href="#sec_3.5." class="tocxref">Typed literals</a></li><li class='tocline'>3.6. <a href="#sec_3.6." class="tocxref">N-Triples</a></li><li class='tocline'>3.7. <a href="#sec_3.7." class="tocxref">Graphs</a></li><li class='tocline'>3.8. <a href="#sec_3.8." class="tocxref">Compact URIs</a></li><li class='tocline'>3.9. <a href="#sec_3.9." class="tocxref">A description of RDFa in RDF terms</a></li></ul></li><li class='tocline'>4. <a href="#s_conformance" class="tocxref">Conformance Requirements</a> <ul class="toc"><li class='tocline'>4.1. <a href="#docconf" class="tocxref">Document Conformance</a></li><li class='tocline'>4.2. <a href="#uaconf" class="tocxref">User Agent Conformance</a></li><li class='tocline'>4.3. <a href="#processorconf" class="tocxref">RDFa Processor Conformance</a></li></ul></li><li class='tocline'>5. <a href="#s_model" class="tocxref">Processing Model</a> <ul class="toc"><li class='tocline'>5.1. <a href="#sec_5.1." class="tocxref">Overview</a></li><li class='tocline'>5.2. <a href="#sec_5.2." class="tocxref">Evaluation Context</a></li><li class='tocline'>5.3. <a href="#sec_5.3." class="tocxref">Processing</a></li></ul></li><li class='tocline'>6. <a href="#s_rdfaindetail" class="tocxref">RDFa in detail</a> <ul class="toc"><li class='tocline'>6.1. <a href="#sec_6.1." class="tocxref">Changing the evaluation context</a> <ul class="toc"><li class='tocline'>6.1.1. <a href="#sec_6.1.1." class="tocxref">Setting the [current resource]</a></li></ul></li><li class='tocline'>6.2. <a href="#sec_6.2." class="tocxref">Object resolution</a> <ul class="toc"><li class='tocline'>6.2.1. <a href="#sec_6.2.1." class="tocxref">Literal object resolution</a></li><li class='tocline'>6.2.2. <a href="#sec_6.2.2." class="tocxref">URI object resolution</a></li></ul></li></ul></li><li class='tocline'>7. <a href="#s_curies" class="tocxref">CURIE Syntax Definition</a></li><li class='tocline'>8. <a href="#s_xhtmlrdfa" class="tocxref">XHTML+RDFa Definition</a></li><li class='tocline'>9. <a href="#s_metaAttributes" class="tocxref">Metainformation Attributes Module</a> <ul class="toc"><li class='tocline'>9.1. <a href="#sec_9.1." class="tocxref">Datatypes</a></li><li class='tocline'>9.2. <a href="#col_Metainformation" class="tocxref">Metadata Attribute Collection</a> <ul class="toc"><li class='tocline'>9.2.1. <a href="#sec_9.2.1." class="tocxref">The about attribute</a></li><li class='tocline'>9.2.2. <a href="#sec_9.2.2." class="tocxref">The content attribute</a></li><li class='tocline'>9.2.3. <a href="#sec_9.2.3." class="tocxref">The datatype attribute</a></li><li class='tocline'>9.2.4. <a href="#sec_9.2.4." class="tocxref">The instanceof attribute</a></li><li class='tocline'>9.2.5. <a href="#sec_9.2.5." class="tocxref">The property attribute</a></li><li class='tocline'>9.2.6. <a href="#sec_9.2.6." class="tocxref">The rel attribute</a></li><li class='tocline'>9.2.7. <a href="#sec_9.2.7." class="tocxref">The resource attribute</a></li><li class='tocline'>9.2.8. <a href="#sec_9.2.8." class="tocxref">The rev attribute</a></li></ul></li></ul></li><li class='tocline'>A. <a href="#a_hostlanguages" class="tocxref">Other Host Languages</a></li><li class='tocline'>B. <a href="#a_xhtmlrdfadtd" class="tocxref">XHTML+RDFa DTD</a> <ul class="toc"><li class='tocline'>B.1. <a href="#a_DTD_xhtml_metaAttributes_module" class="tocxref">XHTML RDFa Module</a></li><li class='tocline'>B.2. <a href="#a_DTD_content_model" class="tocxref">XHTML+RDFa Content Model Module</a></li><li class='tocline'>B.3. <a href="#a_DTD_driver" class="tocxref">XHTML+RDFa Driver Module</a></li><li class='tocline'>B.4. <a href="#a_xhtml11_catalog" class="tocxref">SGML Open Catalog Entry for XHTML+RDFa</a></li></ul></li><li class='tocline'>C. <a href="#a_references" class="tocxref">References</a> <ul class="toc"><li class='tocline'>C.1. <a href="#sec_C.1." class="tocxref">Related Specifications</a></li><li class='tocline'>C.2. <a href="#sec_C.2." class="tocxref">Related Activities</a></li></ul></li><li class='tocline'>D. <a href="#a_history" class="tocxref">Change History</a></li><li class='tocline'>E. <a href="#a_acks" class="tocxref">Acknowledgments</a></li></ul></div><!--OddPage--><h1><a id="s_motivation" name="s_motivation">1. Motivation</a></h1><p><em>This section is informative.</em></p><p>RDF/XML <a href="#RDF-SYNTAX">[RDF-SYNTAX]</a> provides sufficient flexibility to represent all of the abstract concepts in RDF <a href="#RDF-CONCEPTS">[RDF-CONCEPTS]</a>. However, it presents twochallenges; first it is difficult or impossible to validate documents that contain RDF/XML using XML Schemas or DTDs, which makes it difficult to import RDF/XML into other markup languages. Whilstnewer schema languages such as RELAX NG <a href="#RELAXNG">[RELAXNG]</a> do provide a way to validate documents that contain arbitrary RDF/XML, it will be a while before they gain wide support.</p><p>Second, even if one could add RDF/XML directly into an XML dialect like XHTML, there would be significant data duplication between the rendered data and the RDF/XML structured data. It would befar better to add RDF to a document without repeating the document's existing data. For example, an XHTML document that explicitly renders its author's name in the text—perhaps as a byline on anews site—should not need to repeat this name for the RDF expression of the same concept: it should be possible to supplement the existing markup in such a way that it can also be interpretedas RDF.</p><p>Third, as users often want to transfer structured data from one application to another, sometimes to or from a non-web-based application, it is highly beneficial to express the web data'sstructure "in context." The user experience could then be enhanced, for example by providing contextual information about specific rendered data, perhaps when the user "right-clicks" on an item ofinterest.</p><p>In the past, many attributes were 'hard-wired' directly into the markup language to represent specific concepts. For example, in XHTML 1.1 [<a class="nref" href="#ref_XHTML11">XHTML11</a>] andHTML [<a class="nref" href="#ref_HTML4">HTML4</a>] there is <span class="aref">@cite</span>; the attribute allows an author to add information to a document which is used to indicate the origin of aquote.</p><p>However, these 'hard-wired' attributes make it difficult to define a generic process for extracting metadata from any document since a parser would need to know about each of the specialattributes. One motivation for RDFa has been to devise a means by which documents can be augmented with metadata in a general rather than hard-wired manner. This has been achieved by creating a fixedset of attributes and parsing rules, but allowing those attributes to contain properties from any of a number of the growing range of available RDF vocabularies. The <em>values</em> of thoseproperties are in most cases the information that is already in an author's XHTML document.</p><p>RDFa alleviates the pressure on XML format authors to anticipate all the structural requirements users of their format might have, by outlining a new syntax for RDF that relies only on XMLattributes. This specification deals specifically with the use of RDFa in XHTML, and defines an RDF mapping for a number of XHTML attributes, but RDFa can be easily imported into other XML-basedmarkup languages.</p><!--OddPage--><h1><a id="s_Syntax_overview" name="s_Syntax_overview">2. Syntax Overview</a></h1><p><em>This section is informative.</em></p><p>The following examples are intended to help readers who are not familiar with RDFa to quickly get a sense of how it works. For a more thorough introduction, please read the RDFa Primer [<a class= "nref" href="#ref_RDFaPRIMER">RDFaPRIMER</a>].</p><h2><a id="sec_2.1." name="sec_2.1.">2.1. The RDFa Attributes</a></h2><p>RDFa in XHTML makes use of a number of XHTML attributes, as well as providing a few new ones. Attributes that already exist in XHTML will have the same meaning as in XHTML, although their syntaxmay be slightly modified. For example, in XHTML, <span class="aref">@rel</span> already defines the relationship between one document and another. However, in XHTML there is no clear way to add newvalues; RDFa sets out to explicitly solve this problem, and does so by allowing URIs as values. It also introduces the idea of 'compact URIs'—referred to as CURIEs in this document—whichallow a full URI value to be expressed succinctly.</p><p>The XHTML attributes that are relevant are:</p><dl><dt><span class="aref">@rel</span>,</dt><dd>a whitespace separated list of <span class="datatype"><a href="#dt_curie">CURIE</a></span>s, used for expressing relationships between two resources (a 'predicate' in RDF)</dd><dt><span class="aref">@rev</span>,</dt><dd>a whitespace separated list of <span class="datatype"><a href="#dt_curie">CURIE</a></span>s, used for expressing reverse relationships between two resources (also a 'predicate')</dd><dt><span class="aref">@href</span>,</dt><dd>a URI for expressing the partner resource of a relationship (the 'object' in RDF)</dd><dt><span class="aref">@src</span>,</dt><dd>a <span class="datatype"><a href="http://www.w3.org/TR/xhtml-modularization/abstraction.html#dt_URI">URI</a></span> for expressing the partner resource of a relationship when the resource isembedded (also an 'object')</dd></dl><br /><br /><p>The new—RDFa-specific—attributes are:</p><dl><dt><span class="aref">@about</span>,</dt><dd>a <span class="datatype"><a href="#dt_uriorcurie">URIorCURIE</a></span>, used for stating what the data is about (the 'subject' in RDF terminology)</dd><dt><span class="aref">@property</span>,</dt><dd>a whitespace separated list of <span class="datatype"><a href="#dt_curie">CURIE</a></span>s, used for expressing relationships between the subject and some literal text (also a 'predicate')</dd><dt><span class="aref">@resource</span>,</dt><dd>a <span class="datatype"><a href="#dt_uriorcurie">URIorCURIE</a></span> for expressing the partner resource of a relationship that is not intended to be 'clickable' (also an 'object')</dd><dt><span class="aref">@datatype</span>,</dt><dd>a <span class="datatype"><a href="#dt_curie">CURIE</a></span> representing a datatype, to express the datatype of a literal</dd><dt><span class="aref">@content</span>,</dt><dd>a string, for supplying alternative, machine-readable content for a literal.</dd><dt><span class="aref">@instanceof</span></dt><dd>a whitespace separated list of <span class="datatype"><a href="#dt_curie">CURIE</a></span>s that indicate the RDF type(s) to associate with the subject.</dd></dl><br /><br /><p><em>For a normative definition of these attributes see the <a href="#s_metaAttributes">XHTML Metainformation Attributes Module</a>.</em></p><h2><a id="sec_2.2." name="sec_2.2.">2.2. Examples</a></h2><p>As an XHTML author you will already be familiar with using <code>meta</code> and <code>link</code> to add additional information to your documents:</p><div class="example"><pre><html xmlns="http://www.w3.org/1999/xhtml"> <head> <title>Page 7</title> <span class='hilite'><meta name="author" content="Mark Birbeck" /></span> <span class='hilite'><link rel="prev" href="page6.html" /></span> <span class='hilite'><link rel="next" href="page8.html" /></span> </head> <body>...</body></html></pre></div><p>RDFa makes use of this concept, enhancing it with the ability to make use of other vocabularies by using compact URIs:</p><div class="example"><pre><html xmlns="http://www.w3.org/1999/xhtml" <span class='hilite'>xmlns:foaf="http://xmlns.com/foaf/0.1/"</span> <span class='hilite'>xmlns:dc="http://purl.org/dc/elements/1.1/"</span>> <head> <title>My home-page</title> <meta property="<span class='hilite'>dc:creator</span>" content="Mark Birbeck" /> <link rel="<span class='hilite'>foaf:workplaceHomepage</span>" href="http://www.formsPlayer.com/" /> </head> <body>...</body></html></pre></div><p>Although not widely used, XHTML already supports the use of <span class="aref">@rel</span> and <span class="aref">@rev</span> on the <code>a</code> element. This becomes more useful in RDFa withthe addition of support for different vocabularies:</p><div class="example"><pre>This document is licensed under a <a <span class='hilite'>xmlns:cc="http://creativecommons.org/licenses/"</span> <span class='hilite'>rel="cc:license"</span> href="http://creativecommons.org/licenses/by/nc-nd/3.0/"> Creative Commons License</a>.</pre></div><p>Not only can URLs in the document be re-used to provide metadata, but so can inline text:</p><div class="example"><pre><html xmlns="http://www.w3.org/1999/xhtml" <span class='hilite'>xmlns:cal="http://www.w3.org/2002/12/cal/ical#"</span> > <head><title>Jo's Friends and Family Blog</title></head> <body> <p> I'm holding <span <span class='hilite'>property="cal:summary"</span>> <span class='hilite'>one last summer Barbecue</span> </span>, on September 16th at 4pm. </p> </body></html></pre></div><p>If some displayed text is different to the actual 'value' it represents, more precise values can be added, which can optionally include datatypes:</p><div class="example"><pre><html xmlns="http://www.w3.org/1999/xhtml" xmlns:cal="http://www.w3.org/2002/12/cal/ical#" <span class='hilite'>xmlns:xsd="http://www.w3.org/2001/XMLSchema"</span> > <head><title>Jo's Friends and Family Blog</title></head> <body> <p> I'm holding <span property="cal:summary"> one last summer Barbecue </span>, on <span <span class='hilite'>property="cal:dtstart"</span> <span class='hilite'>content="20070916T1600-0500"</span> <span class='hilite'>datatype="xsd:datetime"</span>> September 16th at 4pm </span>. </p> </body></html></pre></div><p>In many cases a block of mark-up will contain a number of properties that relate to the same item; it's possible with RDFa to indicate the type of that item:</p><div class="example"><pre><html xmlns="http://www.w3.org/1999/xhtml" xmlns:cal="http://www.w3.org/2002/12/cal/ical#" xmlns:xsd="http://www.w3.org/2001/XMLSchema" > <head><title>Jo's Friends and Family Blog</title></head> <body> <p <span class='hilite'>instanceof="cal:Vevent"</span>> I'm holding <span property="cal:summary"> one last summer Barbecue </span>, on <span property="cal:dtstart" content="20070916T1600-0500" datatype="xsd:datetime"> September 16th at 4pm </span>. </p> </body></html></pre></div><p>The metadata features available in XHTML only allow information to be expressed about the document itself. RDFa provides a means of referring to other documents and resources:</p><div class="example"><pre><html xmlns="http://www.w3.org/1999/xhtml" xmlns:bib="http://example.org/"> <head> <title>Books by Marco Pierre White</title> </head> <body> I think <span <span class='hilite'>about="urn:ISBN:0091808189"</span> <span class='hilite'>instanceof="bib:book"</span>> White's book 'Canteen Cuisine' </span> is well worth getting since although it's quite advanced stuff, he makes it pretty easy to follow. You might also like his <span <span class='hilite'>about="urn:ISBN:1596913614"</span> <span class='hilite'>instanceof="bib:book"</span>> autobiography </span>. </body></html></pre></div><!--OddPage--><h1><a id="s_rdfterminology" name="s_rdfterminology">3. RDF Terminology</a></h1><p><em>This section is informative.</em></p><p> The previous section gave examples of typical mark-up in order to illustrate what RDFa in XHTML looks like. But what RDFa in XHTML <em>represents</em> is RDF. In order to author RDFa in XHTML youdo not need to understand RDF, although it would certainly help. However, if you are building a system that consumes the RDF output of an RDFa in XHTML document you will almost certainly need tounderstand RDF. In this section we introduce the basic concepts, and terminology of RDF. For a more thorough explanation of RDF, please refer to the RDF Concepts document [<a class="nref" href= "#ref_RDF-CONCEPTS">RDF-CONCEPTS</a>] and tne RDF Sytax Document [<a class="nref" href="#ref_RDF-SYNTAX">RDF-SYNTAX</a>].</p><h2><a id="sec_3.1." name="sec_3.1.">3.1. Statements</a></h2><p> The structured data that RDFa provides access to is a collection of <em>statements</em>. A statement is a basic unit of information that has been constructed in a specific format to make iteasier to process. In turn, by breaking large sets of information down into a collection of statements, even very complex metadata can be processed using simple rules.</p><p> To illustrate, suppose we have the following set of facts:</p><div class="example"><pre> Albert was born on March 14, 1879, in Germany. There is a picture of him at the web address, http://en.wikipedia.org/wiki/Image:Albert_Einstein_Head.jpg.</pre></div>This would be quite difficult for a machine to interpret, and it is certainly not in a format that could be passed from one data application to another. However, if we convert the information to aset of statements it begins to be more manageable. The same information could therefore be represented by the following shorter 'statements': <div class="example"><pre> Albert was born on March 14, 1879. Albert was born in Germany. Albert has a picture at http://en.wikipedia.org/wiki/Image:Albert_Einstein_Head.jpg.</pre></div><br /><br /><h2><a id="sec_3.2." name="sec_3.2.">3.2. Triples</a></h2><p> To make this information machine-processable, RDF defines a structure for these statements. A statement is formally called a <em>triple</em>, meaning that it is made up of three components. Thefirst is the <em>subject</em> of the triple, and is what we are making our statements about. In these examples the subject is always 'Albert'.</p><p> The second part of a triple is the property of the subject that we want to define. In the examples here, the properties would be 'was born on', 'was born in', and 'has a picture at'. These aremore usually called <em>predicates</em> in RDF.</p><p> The final part of a triple is called the <em>object</em>. In the examples here the object values are 'March 14, 1879', 'Germany', and'http://en.wikipedia.org/wiki/Image:Albert_Einstein_Head.jpg'.</p><h2><a id="sec_3.3." name="sec_3.3.">3.3. URI references</a></h2><p> Breaking complex information into manageable units helps us be specific about our data, but there is still some ambiguity. For example, which 'Albert' are we talking about? If another system hasmore facts about 'Albert', how could we know whether they are about the same person, and so add them to the list of things we know about that person? If we wanted to find people born in Germany, howcould we know that the predicate 'was born in' has the same purpose as the predicate 'birthplace' that exists in some other system? RDF solves this problem by replacing our vague terms with <em>URIreferences</em>.</p><p> URIs are most commonly used to identify web pages, but RDF makes use of them as a way to provide unique identifiers for concepts. For example, we could identify the subject of all of ourstatements by using the DBPedia [?ref] URI for Albert Einstein, rather than 'Albert':</p><div class="example"><pre> <http://dbpedia.org/resource/Albert_Einstein> has the name Albert Einstein. <http://dbpedia.org/resource/Albert_Einstein> was born on March 14, 1879. <http://dbpedia.org/resource/Albert_Einstein> was born in Germany. <http://dbpedia.org/resource/Albert_Einstein> has a picture at http://en.wikipedia.org/wiki/Image:Albert_Einstein_Head.jpg.</pre></div><br /><br /><p> URI references are also used to uniquely identify the objects in metadata statements. The picture of Einstein is already a URI, but we can also use one to uniquely identify the country Germany(note that we put literals into quotes to distinguish them from URIs):</p><div class="example"><pre> <http://dbpedia.org/resource/Albert_Einstein> has the name <span class='hilite'>"</span>Albert Einstein<span class='hilite'>"</span>. <http://dbpedia.org/resource/Albert_Einstein> was born on <span class='hilite'>"</span>March 14, 1879<span class='hilite'>"</span>. <http://dbpedia.org/resource/Albert_Einstein> was born in <span class='hilite'><http://dbpedia.org/resource/Germany></span>. <http://dbpedia.org/resource/Albert_Einstein> has a picture at <span class='hilite'><</span>http://en.wikipedia.org/wiki/Image:Albert_Einstein_Head.jpg<span class='hilite'>></span>.</pre></div><br /><br /><p> URI references are also used to ensure that predicates are unambiguous; now we can be sure that 'birthplace', 'place of birth', 'place de nee' [???] and so on, all mean the same thing:</p><div class="example"><pre> <http://dbpedia.org/resource/Albert_Einstein> <span class='hilite'><http://xmlns.com/foaf/0.1/name></span> "Albert Einstein". <http://dbpedia.org/resource/Albert_Einstein> <span class='hilite'><http://dbpedia.org/property/dateOfBirth></span> "March 14, 1879". <http://dbpedia.org/resource/Albert_Einstein> <span class='hilite'><http://dbpedia.org/property/birthPlace></span> <http://dbpedia.org/resource/Germany>. <http://dbpedia.org/resource/Albert_Einstein> <span class='hilite'><http://xmlns.com/foaf/0.1/depiction></span> <http://en.wikipedia.org/wiki/Image:Albert_Einstein_Head.jpg>.</pre></div><br /><br /><h2><a id="sec_3.4." name="sec_3.4.">3.4. Plain literals</a></h2><p> Although URI resources are always used for subjects and predicates, the object part of a triple can be either a URI or a <em>literal</em>. In the example triples, Einstein's name is representedby a <em>plain literal</em>, which means that it is a basic string with no type or language information:</p><div class="example"><pre> <http://dbpedia.org/resource/Albert_Einstein> <http://xmlns.com/foaf/0.1/name> "Albert Einstein".</pre></div><br /><br /><h2><a id="sec_3.5." name="sec_3.5.">3.5. Typed literals</a></h2><p> Some literals, such as dates and numbers, have very specific meanings, so RDF provides a mechanism for indicating the type of a literal. A <em>typed literal</em> is indicated by attaching a URIto the end of a plain literal, and this URI indicates the literal's datatype. This URI is usually based on datatypes defined in the XML Schema Datatypes specification [<a class="nref" href= "#ref_XMLSCHEMA">XMLSCHEMA</a>]. The following syntax would be used to unambiguously express Einstein's date of birth as a literal of type < code>http://www.w3.org/2001/XMLSchema#date:</p><div class="example"><pre> <http://dbpedia.org/resource/Albert_Einstein> <http://dbpedia.org/property/dateOfBirth> "1879-03-14"^^<http://www.w3.org/2001/XMLSchema#date>.</pre></div><br /><br /><h2><a id="sec_3.6." name="sec_3.6.">3.6. N-Triples</a></h2><p> RDF itself does not have one set way to express triples, since the key ideas of RDF are the triple and the use of URIs, and <em>not</em> any particular syntax. However, there are a number ofmechanisms, such as RDF/XML, N-Triples <a href="#N-TRIPLES">[N-TRIPLES]</a>, and of course RDFa. Most discussions of RDF make use of the <em>N-Triple</em> syntax to explain their ideas, since it isquite compact. The examples we have just seen are already using this syntax, and we'll continue to use it throughout this document when we need to talk about the RDF that could be generated from someRDFa. There is one small change that we make to N-Triples, which is to allow long URIs to be abbreviated by using a URI mapping. This is indicated by expressing a compact URI as follows:</p><div class="example"><pre> <http://dbpedia.org/resource/Albert_Einstein> <span class='hilite'>foaf:name</span> "Albert Einstein" . <http://dbpedia.org/resource/Albert_Einstein> <span class='hilite'>p:dateOfBirth</span> "1879-03-14"^^xsd:date . <http://dbpedia.org/resource/Albert_Einstein> <span class='hilite'>p:birthPlace</span> <http://dbpedia.org/resource/Germany>. <http://dbpedia.org/resource/Albert_Einstein> <span class='hilite'>foaf:depiction</span> <http://en.wikipedia.org/wiki/Image:Albert_Einstein_Head.jpg>.</pre></div><p><em>Here 'p:' has been mapped to the URI for DBPedia, and 'foaf:' has been mapped to the URI for the 'Friend of a Friend' taxonomy.</em></p><p>Note that this is merely a way to make examples more compact and the actual triples generated would always use the full URIs.</p><p> When writing examples, you will often see the following URI:</p><div class="example"><pre> <></pre></div>This indicates the 'current document', i.e., the document being processed. In reality there would always be a full URI, but this serves to make examples more compact.<br /><br /><h2><a id="sec_3.7." name="sec_3.7.">3.7. Graphs</a></h2><p> A collection of triples is called a <em>graph</em>.</p><p> For more information on the concepts described above, see <a href="#RDF-CONCEPTS">[RDF-CONCEPTS]</a>. RDFa additionally defines the following terms:</p><h2><a id="sec_3.8." name="sec_3.8.">3.8. Compact URIs</a></h2><p>In order to allow for the compact expression of RDF statements, RDFa allows the contraction of all [URI reference]s into a form called a 'compact URI', or [CURIE]. Until recently QNames [QNames]have been the most common way to abbreviate URIs, but there is a well-known limitation that the syntax for QNames does not allow all possible [URI reference]s to be expressed. CURIEs have beenspecificially designed to look like QNames, but at the same time to get around their syntactic limitations.</p><p>Note that CURIEs are only used in the mark-up and N-Triples examples, and will never appear in the generated [triple]s, which will always use [URI reference]s.</p><h2><a id="sec_3.9." name="sec_3.9.">3.9. A description of RDFa in RDF terms</a></h2><p> The following is a brief description of RDFa in terms of the RDF terminology introduced here. It may be useful to readers with an RDF background:</p><p>The aim of RDFa is to allow a single [RDF graph]s to be carried in XML documents of any type, although this specification deals only with RDFa in XHTML. An [RDF graph] comprises [node]s linked byrelationships. The basic unit of a graph is a [triple], in which a subject [node] is linked to an object [node] via a [predicate]. The subject [node] is always either an [URI reference] or a [blanknode], the predicate is <em>always</em> an [URI reference], and the object of a statement can be an [URI reference], a [literal], or a [blank node].</p><p>In RDFa, a subject [URI reference] is generally indicated using <span class="aref">@about</span>, and predicates are represented using one of <span class="aref">@property</span>, <span class="aref">@instanceof</span>, <span class="aref">@rel</span>, or <span class="aref">@rev</span>. Objects which are [URI reference]s are represented using <span class="aref">@href</span>, <span class= "aref">@resource</span> or <span class="aref">@src</span>, whilst objects that are [literal]s are represented either with <span class="aref">@content</span> (with an optional [datatype] expressedusing <span class="aref">@datatype</span>), or the content of the element in question.</p><!--OddPage--><h1><a id="s_conformance" name="s_conformance">4. Conformance Requirements</a></h1><p><em>This section is normative.</em></p><p>The keywords "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in [<a class="nref" href= "#ref_RFC2119">RFC2119</a>].</p><p>Note that all examples in this document are informative, and are not meant to be interpreted as normative requirements.</p><h2><a id="docconf" name="docconf">4.1. Document Conformance</a></h2><p>A strictly conforming XHTML+RDFa document is a document that requires only the facilities described as mandatory in this specification. Such a document MUST meet all the following criteria:</p><ol><li><p><span class="must">The document must conform to the constraints expressed in the schemas in <!-- <a href="xhtml11_schema.html#a_xhtml11_schema">Appendix D -XHTML 1.1 Schema</a> and--> <a href="#a_xhtmlrdfa_dtd">Appendix B - XHTML+RDFa Document Type Definition</a>.</span></p></li><li><p><span class="must">The local part of the root element of the document must be <code>html</code>.</span></p></li><li><p><span class="must">The start tag of the root element of the document must explicitly contain an <code>xmlns</code> declaration for the XHTML namespace [<a class="nref" href="#ref_XMLNS">XMLNS</a>]. The namespace URI for XHTML is defined to be <code>http://www.w3.org/1999/xhtml</code>.</span></p><!-- <p><span class="may" >The start tag may also contain an <code>xsi:schemaLocation</code> attribute that associates this namespace with the XML Schema at theURI <code><xmlschemaloc></code>.</span></p><!-- ....................................................................... --><!-- XHTML 1.1 + RDFa DTD ................................................. --><!-- file: xhtml-rdfa.dtd--><div class="example"><p>Sample root element</p><pre><html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" ></pre></div></li><!-- XHTML 1.1 + RDFa DTD<li><p><span class="must">There MUST be a DOCTYPE declaration in the document prior to the root element.</span> <span class="must">If present, the public identifier included in the DOCTYPE declarationmust reference the DTD found in <a href="#a_xhtmlrdfa_dtd">Appendix B - XHTML+RDFa Document Type Definition</a> using its Public Identifier.</span> <span class="may">The system identifier may bemodified appropriately.</span></p><pre><!DOCTYPE html PUBLIC "-//W3C//DTD XHTML+RDFa 1.0//EN" "http://www.w3.org/MarkUp/DTD/xhtml-rdfa-1.dtd"></pre></li></ol><div class="example"><p>Example of an XHTML+RDFa 1.0 document</p><pre><?xml version="1.0" encoding="UTF-8"?><!DOCTYPE html PUBLIC "-//W3C//DTD XHTML+RDFa 1.0//EN" "http://www.w3.org/MarkUp/DTD/xhtml-rdfa-1.dtd" ><html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en"> <head> <title>Virtual Library</title> </head> <body> <p>Moved to <a href="http://example.org/">example.org</a>.</p> </body></html></pre></div><p>Note that in this example, the XML declaration is included. An XML declaration like the one above is not required in all XML documents. <span class="should">XHTML document authors should use XMLdeclarations in all their documents.</span> <span class="must">XHTML document authors must use an XML declaration when the character encoding of the document is other than the default UTF-8 or UTF-16and no encoding is specified by a higher-level protocol.</span></p><p><span class="should">XHTML 1.1 documents SHOULD be labeled with the Internet Media Type "application/xhtml+xml" as defined in [<a class="nref" href="#ref_RFC3236">RFC3236</a>]</span>. For furtherinformation on using media types with XHTML, see the informative note [<a class="nref" href="#ref_XHTMLMIME">XHTMLMIME</a>].</p><h2><a id="uaconf" name="uaconf">4.2. User Agent Conformance</a></h2><p><span class="must">A conforming user agent MUST support all of the features required in this specification.</span> <span class="must">A conforming user agent must also support the User Agentconformance requirements as defined in XHTML Modularization [<a class="nref" href="#ref_XHTMLMOD">XHTMLMOD</a>] section on "XHTML Family User Agent Conformance".</span></p><h2><a id="processorconf" name="processorconf">4.3. RDFa Processor Conformance</a></h2><p><span class="must">A conforming RDFa Processor MUST support the extraction of RDF triples using the methodology defined in <a href="#s_model">Processing Model</a>.</span></p><p><span class="must">A conforming RDFa Processor MUST process whitespace according to the rules of [<a class="nref" href="#ref_CSS2">CSS2</a>].</span> <em>Note that this same requirement is imposedupon conforming User Agents via [<a class="nref" href="#ref_XHTMLMOD">XHTMLMOD</a>].</em></p><div class="issue"><p id="s_conformance_issue_0" class="issueTitle">Test Suite</p>We have a test suite - we should likely reference it here, but I need to find the exact way to do that. -Shane</div><div class="issue"><p id="s_conformance_issue_1" class="issueTitle">Assertion Annotation</p>All the assertions in this spec need to be annotated with the appropriate markup (must, should, etc.).</div><!--OddPage--><h1><a id="s_model" name="s_model">5. Processing Model</a></h1><p><em>This section is normative.</em></p><p> This section looks at a generic set of processing rules for creating a set of triples that represent the structured data present in an XHTML+RDFa document. Processing need not follow the DOMtraversal technique outlined here, although the effect of following some other manner of processing must be the same as if the processing outlined here were followed. The processing model isexplained using the idea of DOM traversal which makes it easier to describe (particularly in relation to the 'evaluation context').</p><h2><a id="sec_5.1." name="sec_5.1.">5.1. Overview</a></h2><p> Parsing a document for RDFa triples is carried out by starting at the root element of the document, and visiting each of its child elements in turn, applying processing rules. Processing isrecursive in that for each child element the processor also visits each of <em>its</em> child elements, and applies the same processing rules.</p><p> As processing continues, rules are applied which will either generate triples, or change the [evaluation context] information which will be used in subsequent processing. Some of the rules willbe determined by the host language—in this case XHTML—and some of the rules will be part of RDFa.</p><p> Note that we don't say anything about what should happen to the triples generated, or whether more triples might be generated during processing than are outlined here. However, to be conformant,an RDFa processor needs to act as if at a minimum the rules in this section are applied.</p><h2><a id="sec_5.2." name="sec_5.2.">5.2. Evaluation Context</a></h2><p> During processing, each rule is applied within an 'evaluation context'. Rules may further modify this evaluation context, or create triples that can be established by making use of thisevaluation context. The context itself consists of the following pieces of information:</p><ul><li>The [base]. This will usually be the URL of the document being processed, but it could be some other URL, set by some other mechanism, such as the XHTML <code>base</code> element. The importantthing is that it establishes a URL against which relative paths can be evaluated.</li><li>The [current resource]. The initial value will be the same as the initial value of <code>base</code>, but it will usually change during the course of processing.</li><li>The [current element identifier]. This is an identifier for the current element, which will not always be the same as [current resource].</li><li>A list of current in-scope [URI mappings].</li><li>The [language]. Note that there is no default language.</li></ul><br /><br /><h2><a id="sec_5.3." name="sec_5.3.">5.3. Processing</a></h2><p> Processing would normally begin after the document to be parsed has been completely loaded. However, there is no requirement for this to be the case, and it is certainly possible to use astream-based approach, such as SAX [http://en.wikipedia.org/wiki/SAX] to extract the RDFa information. However, if some approach other than the DOM traversal technique defined here is used, it isimportant to ensure that any <code>meta</code> or <code>link</code> elements processed in the <code>head</code> of the document honour any occurrences of <code>base</code> which may appear <em>after</em> those elements. (In other words, XHTML processing rules must still be applied, even if document processing takes place in a non-HTML environment such as a search indexer.)</p><p> At the beginning of processing, the [current evaluation context] is initialised as follows:</p><ul><li>the [base] is set to either the URL of the document or the value specified in the <code>base</code> element, if present;</li><li>the [current resource] is set to the [base] value;</li><li>the [current element identifier] is cleared;</li><li>the [list of URI mappings] is cleared;</li><li>the [language] is cleared.</li></ul><br /><br /><p> Processing then begins with the root element, and all nodes in the tree are processed according to the following rules, depth-first:</p><ol><li>Any changes to the [current evaluation context] are made first: <ul><li>the [current element] is parsed for [URI mappings] and these are added to the [list of URI mappings]. Note that a [URI mapping] will simply overwrite any current mapping in the list that has thesame name; <div class="explanation">These mappings are provided by <span class="aref">@xmlns</span>. The value to be mapped is set by the XML namespace prefix, and the value to map is the value of theattribute—a URI. Note that the URI is not processed in any way; in particular if it is a relative path it is not resolved against the [current base]. Authors are advised to follow best practicefor using namespaces, which includes not using relative paths. (See [xyz].)</div></li><li>the [current element] is parsed for any language information, and [language] is set in the [current evaluation context]; <div class="explanation">Language information can be provided using the general-purpose XML attribute <span class="aref">@xml:lang</span>.</div></li><li>the [current element] is parsed for any subject information, and it is used to set the [current resource] value, in the [current evaluation context]; <div class="explanation">The [current resource] can be set using <span class="aref">@about</span>. Note that the final value of the [current resource] is an absolute IRI, which means that if <spanclass="aref">@about</span> contains a relative path the value must be normalised against [base] in the [current evaluation context], using the algorithm defined in RFC 3986. The value can also beprovided by a CURIE, and is processed as defined in <a href="#s_curies">CURIE Syntax Definition</a>. Note that since this attribute can take both URIs and CURIEs, the latter will have been expressedusing the [safe CURIE] syntax.</div></li><li>the [current element identifier] is set; <div class="explanation">The [current element identifier] is set to the value of <span class="aref">@about</span>, if present, <em>or</em> the value of <span class="aref">@resource</span>, ifpresent, <em>or</em> the value of <span class="aref">@href</span>, if present, <em>or</em> the value of <span class="aref">@src</span>, if present, <em>or</em> a [blank node]. Note that this meansthat the value of the [current element identfier] will not be the same as the [current resource], since in the absence of an attribute to set its value it will be set to a [blank node], whilst[current resource] inherits from its context.<br />Note that the final value of [current element identifier] is an absolute IRI, so any relative paths must be normalised against [base] in the [current evaluation context], using the algorithm definedin RFC 3986. The value might also have been provided by a CURIE, and if so, it is processed as defined in <a href="#s_curies">CURIE Syntax Definition</a>.</div></li><li>the [recurse] flag is set to true; <div class="explanation">Processing will generally continue recursively through the entire tree of nodes available. However, if an author indicates that some branch of the tree should be treated asan XML literal, no further processing should take place on that branch. This flag is used to inhibit this processing.</div></li><li>the [chaining] flag is set to false; <div class="explanation">If a collection of statements is contained by a [URI reference] then this may become the subject of further statements.</div></li></ul></li><li>Once the [current evaluation context] has been set, object resolution is carried out, as follows: <ul><li>the [current object resource] is established; <div class="explanation">Since only one [current object resource] is set per element then some attributes will have a higher priority than others. The highest priority is given to <span class="aref">@resource</span>. If there is no <span class="aref">@resource</span> then <span class="aref">@href</span> is used, and if that is not present, <span class="aref">@src</span> is used. If none of theseare present then a unique identifier or [blank node] is created. Note that the final value of the [current object resource] is an absolute URI or a [blank node], which means that if any of theseattributes contain relative paths they must be normalised against [base] in the [current evaluation context], using the algorithm defined in RFC 3986. Note also that since <span class="aref">@resource</span> can take both URIs and CURIEs, the latter will have been expressed using the [safe CURIE] syntax.</div></li><li>the [current object literal] is established; <div class="explanation">The [current object literal] will be set as a [plain literal] if <span class="aref">@content</span> is present, <em>or</em> the body of the [current element] contains onlytext (i.e., there are no child elements), <em>or</em> the body of the [current element] <em>does</em> have child elements but <span class="aref">@datatype</span> has an empty value. Additionally, ifthere is a value for [current language] then the value of the [plain literal] should include this language information, as described in [RDFCONCEPTS]. The actual literal is either the value of <spanclass="aref">@content</span> (if present) <em>or</em> a string created by concatenating the text content of each of the child elements of the [current element] in document order, and then normalisingwhite-space according to [WHITESPACERULES].</div><div class="issue"><p id="s_model_issue_2" class="issueTitle">Whitespace normalising</p>So far we defer to CSS2, but I think we should copy the prose into here, so that it's clearer.</div><div class="explanation">The [current object literal] will be set as a [typed literal] if <span class="aref">@datatype</span> is present, and does not have an empty value. The actual literal iseither the value of <span class="aref">@content</span> (if present) <em>or</em> a string created by concatenating the inner content of each of the children in turn, of the [current element]. Thefinal string includes the datatype, as described in [RDFCONCEPTS].</div><div class="explanation">The [current object literal] will be set as an [XML literal] if the [current element] has child elements, and <span class="aref">@datatype</span> is not present, or is set to<code>rdf:XMLLiteral</code>. The value of the [XML literal] is a string created from the inner content of the [current element], i.e., not including the element itself, with the datatype of <code>rdf:XMLLiteral</code>.</div></li></ul></li><li>Once object resolution is complete the processor will have two objects, one a resource and the other a literal. These objects can now be used to create triples with the [current resource],depending on the presence of other attributes. This is achieved using the following processing steps: <ul><li>Predicates for the [current object literal] are established; <div class="explanation">Predicates for the [current object literal] can be set by using <span class="aref">@property</span>. If present, the attribute must contain one or more [curie]s, each ofwhich is converted to an absolute URI using CURIE processing rules, and then used to generate a triple as follows: <dl><dt>subject</dt><dd>[current resource]</dd><dt>predicate</dt><dd>expanded value from the curie</dd><dt>object</dt><dd>[current object literal]</dd></dl></div>Note that <em>literal</em> may include language and datatype information as discussed in the section on object resolution. Once the triple has been created, the [recurse] flag is set to false.</li><li>predicates for the [current object resource] are established. If any triples are generated then the [chaining] flag is set to <code>true</code>.; <div class="explanation">Predicates for the [current object resource] can be set by using one or both of the <span class="aref">@rel</span> and <span class="aref">@rev</span> attributes. If present,<span class="aref">@rel</span> must contain one or more [CURIE]s, each of which is converted to an absolute URI using CURIE processing rules, and then used to generate a triple as follows: <dl><dt>subject</dt><dd>[current resource]</dd><dt>predicate</dt><dd>expanded value from the curie</dd><dt>object</dt><dd>[current object resource]</dd></dl><br /> If present, <span class="aref">@rev</span> must contain one or more [CURIE]s, each of which is converted to an absolute URI using CURIE processing rules, and then used to generate a triple asfollows: <dl><dt>subject</dt><dd>[current object resource]</dd><dt>predicate</dt><dd>expanded value from the curie</dd><dt>object</dt><dd>[current resource]</dd></dl><br /></div></li></ul></li><li>Type values for the [current element identifier] are established. If any triples are generated then the [chaining] flag is set to <code>true</code>.; <div class="explanation">One or more 'types' for the [current element identifier] can be set by using <span class="aref">@instanceof</span>. If present, the attribute must contain one or more[curie]s, each of which is converted to an absolute URI using CURIE processing rules, and then used to generate a triple as follows: <dl><dt>subject</dt><dd>[current element identifier]</dd><dt>predicate</dt><dd>http://www.w3.org/1999/02/22-rdf-syntax-ns#type</dd><dt>object</dt><dd>expanded value from the curie</dd></dl></div></li><li>If the [chaining] flag is set to <code>true</code> then the [current resource] is set to the value of the [current object resource], and the [chaining] flag is set to <code>false</code>.</li><li>If the [recurse] flag is true, the [current evaluation context] is pushed onto a stack, and all nodes that are children of the [current element] are processed using the rules described here. Onceall of the children have been processed then the [current evaluation context] is popped back off the stack.</li></ol><br /><br /> <!--OddPage--> <h1><a id="s_rdfaindetail" name="s_rdfaindetail">6. RDFa in detail</a></h1><p><em>This section is normative.</em></p><p> This section provides an in-depth examination of the processing steps described in the previous section. It also includes examples which may help clarify some of the steps involved.</p><div class="issue"><p id="s_rdfaindetail_issue_3" class="issueTitle">@instanceof situation</p>This section still needs the detail on whether <span class="aref">@instanceof</span> should use <span class="aref">@about</span> if it is present, or use the subject from chaining.</div><p> <strong>NOTE:</strong> There isn't quite enough detail on chaining yet.</p><p>In the following examples, for brevity assume that the following namespace prefixes have been defined:</p><table><tr><td rowspan="1" colspan="1">cc:</td><td rowspan="1" colspan="1">http://creativecommons.org/ns#</td></tr><tr><td rowspan="1" colspan="1">dc:</td><td rowspan="1" colspan="1">http://purl.org/dc/elements/1.1/</td></tr><tr><td rowspan="1" colspan="1">ex:</td><td rowspan="1" colspan="1">http://example.org/</td></tr><tr><td rowspan="1" colspan="1">foaf:</td><td rowspan="1" colspan="1">http://xmlns.com/foaf/0.1/</td></tr><tr><td rowspan="1" colspan="1">rdf:</td><td rowspan="1" colspan="1">http://www.w3.org/1999/02/22-rdf-syntax-ns#</td></tr><tr><td rowspan="1" colspan="1">rdfs:</td><td rowspan="1" colspan="1">http://www.w3.org/2000/01/rdf-schema#</td></tr><tr><td rowspan="1" colspan="1">p:</td><td rowspan="1" colspan="1">http://dbpedia.org/property/</td></tr><tr><td rowspan="1" colspan="1">rdfa:</td><td rowspan="1" colspan="1">http://www.w3.org/ns/rdfa/</td></tr><tr><td rowspan="1" colspan="1">svg:</td><td rowspan="1" colspan="1">http://www.w3.org/2000/svg</td></tr><tr><td rowspan="1" colspan="1">xh11:</td><td rowspan="1" colspan="1">http://www.w3.org/1999/xhtml</td></tr><tr><td rowspan="1" colspan="1">xsd:</td><td rowspan="1" colspan="1">http://www.w3.org/2001/XMLSchema#</td></tr><tr><td rowspan="1" colspan="1">biblio:</td><td rowspan="1" colspan="1">http://example.org/biblio/0.1</td></tr><tr><td rowspan="1" colspan="1">taxo:</td><td rowspan="1" colspan="1">http://purl.org/rss/1.0/modules/taxonomy/</td></tr></table><p> The key to processing is that a triple is generated whenever a predicate/object combination is detected. The actual triple generated will include a subject that may have been set previously, sothis is tracked in the [current evaluation context] and is called the [current resource]. Since the subject will default to the current document if it hasn't been set explicitly, then apredicate/object combination is always enough to generate one or more triples.</p><p> The attributes for setting a predicate are <span class="aref">@rel</span>, <span class="aref">@rev</span> and <span class="aref">@property</span>, whilst the attributes for setting an object are<span class="aref">@resource</span>, <span class="aref">@href</span>, <span class="aref">@content</span>, and <span class="aref">@src</span>.</p><p> Note that there are actually two special cases—the use of <span class="aref">@instanceof</span> to set type information, and <span class="aref">@rel</span> or <span class="aref">@rev</span>appearing on an element on its own. Both of these cases are discussed in more details below.</p><h2><a id="sec_6.1." name="sec_6.1.">6.1. Changing the evaluation context</a></h2><h3><a id="sec_6.1.1." name="sec_6.1.1.">6.1.1. Setting the [current resource]</a></h3><p>When triples are created they will always be in relation to the [current resource]. When parsing begins the [current resource] will be the URI of the document being parsed, or a value as set by<code>base</code>.</p><p>Metadata about the document itself is usually placed in the <code>head</code>:</p><div class="example"><pre><html> <head> <title>Jo's Friends and Family Blog</title> <span class='hilite'><link rel="foaf:primaryTopic" href="#bbq" /></span> <span class='hilite'><meta property="dc:creator" content="Jo" /></span> </head> <body> ... </body></html></pre></div><p>although it is possible for the data to appear elsewhere:</p><div class="example"><pre><html> <head> <title>Jo's Blog</title> </head> <body> <h1><span class='hilite'><span property="dc:creator">Jo</span></span>'s blog</h1> <p> Welcome to my blog. </p> </body></html></pre></div><p>The value of <code>base</code> may change the initial value of [current resource]:</p><div class="example"><pre><html> <head> <title>Jo's Friends and Family Blog</title> <link rel="foaf:primaryTopic" href="#bbq" /> <meta property="dc:creator" content="Jo" /> <span class='hilite'><base href="http://www.example.org/jo/blog" /></span> </head> <body> ... </body></html></pre></div><p>As processing progresses, any <span class="aref">@about</span> attributes will change the [current resource]. The value of <span class="aref">@about</span> is a URI or a CURIE. If it is a relativeURI then it needs to be resolved against the current [base] value. In this mark-up the properties <code>cal:summary</code> and <code>cal:dtstart</code> become part of the 'event' object, rather thanreferring to the document:</p><div class="example"><pre><html> <head> <title>Jo's Friends and Family Blog</title> <link rel="foaf:primaryTopic" href="#bbq" /> <meta property="dc:creator" content="Jo" /> </head> <body> <p <span class='hilite'>about="#bbq"</span> instanceof="cal:Vevent"> I'm holding <span <span class='hilite'>property="cal:summary"</span>> one last summer Barbecue </span>, on <span <span class='hilite'>property="cal:dtstart"</span> content="20070916T1600-0500" datatype="xsd:datetime"> September 16th at 4pm </span>. </p> </body></html></pre></div><p>Other kinds of resources can be used to set the [current resource], not just references to web-pages:</p><div class="example"><pre>Daniel knows<a <span class='hilite'>about="mailto:daniel.brickley@bristol.ac.uk"</span> rel="foaf:knows" href="mailto:libby.miller@bristol.ac.uk">Libby</a>.Libby knows<a <span class='hilite'>about="mailto:libby.miller@bristol.ac.uk"</span> rel="foaf:knows" href="mailto:ian.sealy@bristol.ac.uk">Ian</a>.</pre></div><div class="example"><pre><div <span class='hilite'>about="photo1.jpg"</span>> <span class="attribution-line">this photo was taken by <span property="dc:creator">Mark Birbeck</span> </span></div></pre></div><h2><a id="sec_6.2." name="sec_6.2.">6.2. Object resolution</a></h2><p>There are two types of object, [URI resource]s and [literal]s.</p><p>A [literal] object can be set by using <span class="aref">@property</span> to express a [predicate], and then using either <span class="aref">@content</span>, or the inline text of the elementthat <span class="aref">@property</span> is on.</p><p>A [URI resource] object can be set using one of <span class="aref">@rel</span> or <span class="aref">@rev</span> to express a [predicate], and then using one of <span class="aref">@href</span>,<span class="aref">@resource</span> or <span class="aref">@src</span> to provide the object.</p><h3><a id="sec_6.2.1." name="sec_6.2.1.">6.2.1. Literal object resolution</a></h3><p> An [object literal] will be generated when <span class="aref">@property</span> is present. <span class="aref">@property</span> provides the predicate, and the following sections describe how theactual literal to be generated is determined.</p><h4><a id="sec_6.2.1.1." name="sec_6.2.1.1.">6.2.1.1. Plain Literals</a></h4><p><span class="aref">@content</span> can be used to indicate a [plain literal], as follows:</p><div class="example"><pre><meta about="http://internet-apps.blogspot.com/" property="dc:creator" <span class='hilite'>content="Mark Birbeck"</span> /></pre></div><p>The [plain literal] can also be specified by using the content of the element:</p><div class="example"><pre><span about="http://internet-apps.blogspot.com/" property="dc:creator"><span class='hilite'>Mark Birbeck</span></span></pre></div><p> Both of these examples give the following triple:</p><div class="example"><pre> <http://internet-apps.blogspot.com/> dc:creator "Mark Birbeck" .</pre></div><p>The value of <span class="aref">@content</span> attribute is given precedence over any element content, so the following would give exactly the same triple:</p><div class="example"><pre><span about="http://internet-apps.blogspot.com/" property="dc:creator" <span class='hilite'>content="Mark Birbeck"</span>>John Doe</span></pre></div><h5><a id="sec_6.2.1.1.1." name="sec_6.2.1.1.1.">6.2.1.1.1. Language Tags</a></h5><p>RDF allows [plain literal]s to have a language tag, as illustrated by the following example from <a href="#RDFTESTS-RDFMS-XMLLANG-TEST006"> [RDFTESTS-RDFMS-XMLLANG-TEST006]</a>:</p><div class="example"><pre><http://example.org/node> <http://example.org/property> "chat"<span class='hilite'>@fr</span> .</pre></div><p>In RDFa the XML language attribute <span class="aref">@xml:lang</span> is used to add this information, whether the plain literal is designated by <span class="aref">@content</span>, or by theinline text of the element:</p><div class="example"><pre><meta about="http://example.org/node" property="ex:property" <span class='hilite'>xml:lang="fr"</span> content="chat" /></pre></div><p>Note that the language value can be inherited as defined in <a href="#XML-LANG">[XML-LANG]</a>, so the following syntax will give the same triple as above:</p><div class="example"><pre><html xmlns="http://www.w3.org/1999/xhtml" xmlns:ex="http://www.example.com/ns/" <span class='hilite'>xml:lang="fr"</span>> <head> <title xml:lang="en">Example</title> <meta about="http://example.org/node" property="ex:property" content="chat" /> </head> ...</html></pre></div><h4><a id="sec_6.2.1.2." name="sec_6.2.1.2.">6.2.1.2. Typed literals</a></h4><p>[Literal]s can be given a data type using <span class="aref">@datatype</span>.</p><p>This can be represented in RDFa as follows:</p><div class="example"><pre><span property="cal:dtstart" content="20070916T1600-0500" <span class='hilite'>datatype="xsd:datetime"</span>> September 16th at 4pm</span>.</pre></div><p>The triples that this mark-up generates include the datatype after the literal:</p><div class="example"><pre><> cal:dtstart "20070916T1600-0500"^^<span class='hilite'>xsd:datetime</span> .</pre></div><h4><a id="sec_6.2.1.3." name="sec_6.2.1.3.">6.2.1.3. XML Literals</a></h4><p>XML documents cannot contain XML mark-up in their attributes, which means it is not possible to represent XML within <span class="aref">@content</span> (the following would cause an XML parser togenerate an error):</p><div class="example"><pre><head about=""> <meta property="dc:title" <span class='hilite'>content="E = mc<sup>2</sup>: The Most Urgent Problem of Our Time"</span> /></head></pre></div><p>It does not help to escape the content, since the output would simply be a string of text containing numerous ampersands:</p><div class="example"><pre><> dc:title "E = mc<span class='hilite'>&lt;sup&gt;2&amp;lt;/sup&gt;</span>: The Most Urgent Problem of Our Time" .</pre></div><p>RDFa therefore supports the use of normal mark-up to express XML literals, by using <span class="aref">@datatype</span>:</p><div class="example"><pre> <h2 property="dc:title" datatype="rdf:XMLLiteral"> <span class='hilite'>E = mc<sup>2</sup>: The Most Urgent Problem of Our Time</span> </h2></pre></div><p>This would generate the following triple, with the XML preserved in the literal:</p><div class="example"><pre> <> dc:title "E = mc<sup>2</sup>: The Most Urgent Problem of Our Time"^^rdf:XMLLiteral .</pre></div><p> Note that this requires that a URI mapping for the prefix <code>rdf</code> has been defined. To make authoring easier, if there are child elements and no <span class="aref">@datatype</span>attribute, then the effect is the same as if <span class="aref">@datatype</span> have been explicitly set to <code>rdf:XMLLiteral</code>:</p><div class="example"><pre> <h2 property="dc:title"> E = mc<sup>2</sup>: The Most Urgent Problem of Our Time </h2></pre></div><p> In the examples we've been using the <code>sup</code> element is actually part of the meaning of the literal, but there will be situations where the extra mark-up means nothing, and can thereforebe ignored. In this situation an empty <span class="aref">@datatype</span> value can be used to override the XML literal behaviour:</p><div class="example"><pre><p>You searched for <strong>Einstein</strong>:</p><p about="http://dbpedia.org/resource/Albert_Einstein"> <span property="foaf:name" <span class='hilite'>datatype=""</span>>Albert <strong>Einstein</strong></span> (March 14, 1879 – April 18, 1955) was a German-born theoretical physicist.</p></pre></div><p>Although the rendering of this page has highlighted the term the user searched for, setting <span class="aref">@datatype</span> to nothing ensures that the data is interpreted as a plain literal,giving the following triples:</p><div class="example"><pre><http://dbpedia.org/resource/Albert_Einstein> foaf:name <span class='hilite'>"Albert Einstein"</span> .</pre></div><p>Note that the value of this [XML Literal] is the exclusive canonicalization of the RDFa element's value.</p><p> <span class="mustnot">Although the RDFa processing model requires visiting each node in the tree, if the processor meets an [XML literal] then it MUST NOT process any further down thetree.</span> This is to prevent triples being generated from mark-up that is not actually in the hierarchy. For example, we might want to set the title of something to some XHTML that includesRDFa:</p><div class="example"><pre><h2 <span class='hilite'>property="dc:title"</span>> Example 3: <span about="#bbq" instanceof="cal:Vevent">...</span></h2></pre></div><p> This does effectively mean that the presence of <span class="aref">@property</span> without <span class="aref">@content</span> will inhibit any further processing, so authors should watch out forstray attributes, especially if they find that they are getting fewer triples than they had expected.</p><h3><a id="sec_6.2.2." name="sec_6.2.2.">6.2.2. URI object resolution</a></h3><p> One or more [URI object]s are needed when <span class="aref">@rel</span> or <span class="aref">@rev</span> is present. Each attribute will cause triples to be generated when used with <spanclass="aref">@href</span>, <span class="aref">@resource</span> or <span class="aref">@src</span>.</p><p> <span class="aref">@rel</span> and <span class="aref">@rev</span> are essentially the inverse of each other; whilst <span class="aref">@rel</span> establishes a relationship between the [currentresource] as subject, and the [object resource] as the object, <span class="aref">@rev</span> does the exact opposite, and uses the [object resource] as the subject, and the [current resource] as theobject.</p><h4><a id="sec_6.2.2.1." name="sec_6.2.2.1.">6.2.2.1. Using <span class="aref">@resource</span> to set the object</a></h4><p>RDFa provides the <span class="aref">@resource</span> attribute as a way to set the object of statements. This is particularly useful when referring to resources that are not themselves navigablelinks:</p><div class="issue"><p id="s_rdfaindetail_issue_4" class="issueTitle">Need triple</p>This example needs the corresponding triples, but I am too lazy right now. -Shane</div><div class="example"><pre> <html> <head> <title>On Crime and Punishment</title> </head> <body> <blockquote about="#q1" rel="dc:source" <span class='hilite'>resource="urn:isbn:0140449132"</span> > <p id="q1"> Rodion Romanovitch! My dear friend! If you go on in this way you will go mad, I am positive! Drink, pray, if only a few drops! </p> </blockquote> </body> </html></pre></div><h4><a id="sec_6.2.2.2." name="sec_6.2.2.2.">6.2.2.2. Using <span class="aref">@href</span></a></h4><p> If no <span class="aref">@resource</span> is present, then <span class="aref">@href</span> can be used to set the object.</p><p>When a triple predicate has been expressed using <span class="aref">@rel</span>, the <span class="aref">@href</span> on the [RDFa statement]'s element is used to indicate the object as a [URIreference]. Its type, just like that of <span class="aref">@about</span>, is a URI:</p><div class="example"><pre><link about="mailto:daniel.brickley@bristol.ac.uk" <span class='hilite'>rel="foaf:knows" href="mailto:libby.miller@bristol.ac.uk"</span> /></pre></div><p>It's also possible to use both <span class="aref">@rel</span> and <span class="aref">@rev</span> at the same time on an element. This is particularly useful when two things stand in two differentrelationships with each, for example when a picture is taken <em>by</em> Mark, but that picture also <em>depicts</em> him:</p><div class="example"><pre><p>This photo was taken by<a about="photo1.jpg" <span class='hilite'>rel="dc:creator" rev="foaf:img"</span> href="http://www.blogger.com/profile/1109404">Mark Birbeck</a>.</p></pre></div><p>which then yields two triples:</p><div class="example"><pre><photo1.jpg> dc:creator <http://www.blogger.com/profile/1109404> .<http://www.blogger.com/profile/1109404> foaf:img <photo1.jpg> .</pre></div><h4><a id="sec_6.2.2.3." name="sec_6.2.2.3.">6.2.2.3. Using <span class="aref">@about</span> to set the subject</a></h4><div class="example"><pre>This photo, entitled <span <span class='hilite'>about="photo1.jpg"</span> property="dc:title">Portrait of Mark</span>was taken by<a <span class='hilite'>about="photo1.jpg"</span> rel="dc:creator" rev="foaf:img" href="http://www.blogger.com/profile/1109404">Mark himself</a>.</pre></div><p>The value of <span class="aref">@about</span> sets the subject for any nested triples which means that the same triples can be expressed using this, more compact, syntax:</p><div class="example"><pre> <div <span class='hilite'>about="photo1.jpg"</span>> This photo, entitled <span property="dc:title">Portrait of Mark</span> was taken by <a rel="dc:creator" rev="foaf:img" href="http://www.blogger.com/profile/1109404">Mark himself</a>. </div></pre></div><h4><a id="sec_6.2.2.4." name="sec_6.2.2.4.">6.2.2.4. Using a blank node to set the object</a></h4><p>When a triple predicate has been expressed using <span class="aref">@rel</span>, and no <span class="aref">@href</span>, <span class="aref">@src</span>, or <span class="aref">@resource</span>exists on the same [RDFa element], then the <span class="datatype"><a href="#dt_curie">CURIE</a></span> represented by this element is used as the object. This <span class="datatype"><a href= "#dt_curie">CURIE</a></span> is affected by <span class="aref">@about</span>, but if none is present the object is a [blank node] (blank nodes are discussed further in @@@section bnode [REF]@@@). Inall cases, the subject resolution for child elements is affected: where they do not override the subject, their subject is this same <span class="datatype"><a href="#dt_curie">CURIE</a></span> hereresolved as the object.</p><p>Consider, for example, a simple fragment of XHTML for describing the creator of a web page, with further information about the creator, including his name and email address:</p><div class="example"><pre><div rel="dc:creator"> <span property="foaf:name">Ben Adida</span> (<a property="foaf:mbox" href="mailto:ben@adida.net">ben@adida.net</a>)</div></pre></div><p>The above yields the following triples:</p><div class="example"><pre><> dc:creator _:div0 ._:div0 foaf:name "Ben Adida" ._:div0 foaf:mbox <mailto:ben@adida.net> .</pre></div><h5><a id="sec_6.2.2.4.1." name="sec_6.2.2.4.1.">6.2.2.4.1. Referencing Blank Nodes</a></h5><p>To establish relationships between [blank node]s, the [unique anonymous ID] must be set explicity using a CURIE [blank node] as subject or object. For example, if our desired output is thefollowing [triple]s:</p><div class="example"><pre>_:a foaf:mbox <mailto:daniel.brickley@bristol.ac.uk> ._:b foaf:mbox <mailto:libby.miller@bristol.ac.uk> ._:a foaf:knows _:b .</pre></div><p>we could use the following XHTML:</p><div class="example"><pre> <link about="[_:a]" rel="foaf:mbox" href="mailto:daniel.brickley@bristol.ac.uk" /> <link about="[_:b]" rel="foaf:mbox" href="mailto:libby.miller@bristol.ac.uk" /> <link about="[_:a]" rel="foaf:knows" href="[_:b]" /></pre></div><p>or, alternatively, if we wish to partly render the information in XHTML:</p><div class="example"><pre> <div about="[_:a]"> DanBri can be reached via <a rel="foaf:mbox" href="mailto:daniel.brickley@bristol.ac.uk"> email </a>. <span rel="foaf:knows" resource="[_:b]">He knows Libby.</span> </div> <div about="[_:b]"> Libby can be reached via <a rel="foaf:mbox" href="mailto:libby.miller@bristol.ac.uk"> email </a> </div></pre></div><!--OddPage--><h1><a id="s_curies" name="s_curies">7. CURIE Syntax Definition</a></h1><p><i>This section is normative.</i></p><em>Note that this syntax definition will ultimately be defined in an external document [<a class="nref" href="#ref_CURIE">CURIE</a>].</em> <p>The key component of RDF is the URI, but they are usually long and unwieldy. RDFa therefore supports a mechanism by which URIs can be abbreviated, called 'compact URIs' or simply, CURIEs.</p><p>A CURIE is comprised of two components, a <em>prefix</em> which maps to a URI, and a <em>reference</em>. The prefix is separated from the reference by a colon (<code>:</code>). It is possible toomit the prefix, and make use of the default prefix. It is also possible to omit both the prefix <em>and</em> the colon, leaving just a <em>reference</em>.</p><pre><span id="P_curie">curie := [ [ prefix ] ':' ] reference</span>prefix := <a href="http://www.w3.org/TR/1999/REC-xml-names-19990114/#NT-NCName">NCName</a>reference := irelative-ref (as defined in [<a class="nref" href="#ref_IRI">IRI</a>])</pre><p> In some situations an attribute will allow either a CURIE, or a normal IRI. Since it is difficult to distinguish between CURIEs and IRIs, RDFa adds the notion of a [safe CURIE]. The syntax issimply to surround the CURIE with square brackets:</p><pre><span id="P_safe_curie">safe_curie := '[' curie ']'</span></pre><p> <strong>NOTE:</strong> The following language-independent prose will be removed shortly, once we have finalised this.</p><p> To evaluate CURIEs during processing the following context needs to be set:</p><ul><li>a set of mappings from prefixes to URIs; <div class="explanation">The prefix mappings are provided by the current in-scope namespace declarations of the [current element] during parsing.</div></li><li>a mapping to use with the default prefix (for example, <code>:p</code>); <div class="explanation">The mapping to use with the default prefix is the current default namespace.</div></li><li>a mapping to use when there is no prefix (for example, <code>p</code>); <div class="explanation">The mapping to use when there is no prefix is <code>http://www.w3.org/1999/xhtml#</code>.</div></li><li>a mapping to use with the '_' prefix, which is used to generate unique identifiers (for example, <code>_:p</code>). <div class="explanation">the mapping to use with the '_' prefix is not explicitly stated, but should be chosen by the processor to ensure that there is no possibility of collision with otherdocuments.</div></li></ul><br /><br /><div class="issue"><p id="s_curies_issue_5" class="issueTitle">clarify the 'no prefix' situation</p>The advantage of setting the 'no prefix' mapping to the XHTML namespace is that we no longer need a preprocessing step to handle XHTML link types, such as a <code>next</code>. However, this does havethe effect of moving all other values into the XHTML namespace, such as <code>openid.delegate</code>. An alternative is to prohibit unprefixed CURIEs, other than those defined by XHTML.</div><p><span class="must">A CURIE is a representation of a full IRI. This IRI is obtained by taking the currently in-scope mapping that is associated with <code>prefix</code>, and concatenating it withthe <code>reference</code>. The result MUST be a syntactically valid IRI [<a class="nref" href="#ref_IRI">IRI</a>]</span>.</p><!--OddPage--><h1><a id="s_xhtmlrdfa" name="s_xhtmlrdfa">8. XHTML+RDFa Definition</a></h1><p><em>This section is normative.</em></p><p>The XHTML+RDFa document type is a fully functional document type with rich semantics. It is a superset of [<a class="nref" href="#ref_XHTML11">XHTML11</a>]. See that document for the details ofthe underlying language.</p><p>The XHTML+RDFa 1.0 document type is made up of the following XHTML modules. The elements, attributes, and content models associated with these modules are defined in "XHTML Modularization" [<aclass="nref" href="#ref_XHTMLMOD">XHTMLMOD</a>]. The elements are listed here for information purposes, but the definitions in "XHTML Modularization" should be considered authoritative. In theon-line version of this document, the module names in the list below link into the definitions of the modules within the current versions of "XHTML Modularization".</p><dl><dt><a href="http://www.w3.org/TR/xhtml-modularization/abstract_modules.html#s_structuremodule">Structure Module</a></dt><dd><code>body, head, html, title</code></dd><dt><a href="http://www.w3.org/TR/xhtml-modularization/abstract_modules.html#s_textmodule">Text Module</a></dt><dd><code>abbr, acronym, address, blockquote, br, cite, code, dfn, div, em, h1, h2, h3, h4, h5, h6, kbd, p, pre, q, samp, span, strong, var</code></dd><dt><a href="http://www.w3.org/TR/xhtml-modularization/abstract_modules.html#s_hypertextmodule">Hypertext Module</a></dt><dd><code>a</code></dd><dt><a href="http://www.w3.org/TR/xhtml-modularization/abstract_modules.html#s_listmodule">List Module</a></dt><dd><code>dl, dt, dd, ol, ul, li</code></dd><dt><a href="http://www.w3.org/TR/xhtml-modularization/abstract_modules.html#s_objectmodule">Object Module</a></dt><dd><code>object, param</code></dd><dt><a href="http://www.w3.org/TR/xhtml-modularization/abstract_modules.html#s_presentationmodule">Presentation Module</a></dt><dd><code>b, big, hr, i, small, sub, sup, tt</code></dd><dt><a href="http://www.w3.org/TR/xhtml-modularization/abstract_modules.html#s_editmodule">Edit Module</a></dt><dd><code>del, ins</code></dd><dt><a href="http://www.w3.org/TR/xhtml-modularization/abstract_modules.html#s_bdomodule">Bidirectional Text Module</a></dt><dd><code>bdo</code></dd><dt><a href="http://www.w3.org/TR/xhtml-modularization/abstract_modules.html#s_extformsmodule">Forms Module</a></dt><dd><code>button, fieldset, form, input, label, legend, select, optgroup, option, textarea</code></dd><dt><a href="http://www.w3.org/TR/xhtml-modularization/abstract_modules.html#s_tablemodule">Table Module</a></dt><dd><code>caption, col, colgroup, table, tbody, td, tfoot, th, thead, tr</code></dd><dt><a href="http://www.w3.org/TR/xhtml-modularization/abstract_modules.html#s_imagemodule">Image Module</a></dt><dd><code>img</code></dd><dt><a href="http://www.w3.org/TR/xhtml-modularization/abstract_modules.html#s_imapmodule">Client-side Image Map Module</a></dt><dd><code>area, map</code></dd><dt><a href="http://www.w3.org/TR/xhtml-modularization/abstract_modules.html#s_servermapmodule">Server-side Image Map Module</a></dt><dd>Attribute <code>ismap</code> on <code>img</code></dd><dt><a href="http://www.w3.org/TR/xhtml-modularization/abstract_modules.html#s_intrinsiceventsmodule">Intrinsic Events Module</a></dt><dd>Events attributes</dd><dt><a href="http://www.w3.org/TR/xhtml-modularization/abstract_modules.html#s_metamodule">Metainformation Module</a></dt><dd><code>meta</code></dd><dt><a href="http://www.w3.org/TR/xhtml-modularization/abstract_modules.html#s_scriptmodule">Scripting Module</a></dt><dd><code>noscript, script</code></dd><dt><a href="http://www.w3.org/TR/xhtml-modularization/abstract_modules.html#s_stylemodule">Stylesheet Module</a></dt><dd><code>style</code> element</dd><dt><a href="http://www.w3.org/TR/xhtml-modularization/abstract_modules.html#s_styleattributemodule">Style Attribute Module</a> <em>Deprecated</em></dt><dd><span class="aref">@style</span></dd><dt><a href="http://www.w3.org/TR/xhtml-modularization/abstract_modules.html#s_targetattributemodule">Target Attribute Module</a></dt><dd><span class="aref">@target</span></dd><dt><a href="http://www.w3.org/TR/xhtml-modularization/abstract_modules.html#s_linkmodule">Link Module</a></dt><dd><code>link</code></dd><dt><a href="http://www.w3.org/TR/xhtml-modularization/abstract_modules.html#s_basemodule">Base Module</a></dt><dd><code>base</code></dd><dt><a href="#s_metaAttributes">Metainformation Attributes Module</a></dt><dd><span class="aref">@about</span>, <span class="aref">@content</span>, <span class="aref">@datatype</span>, <span class="aref">@instanceof</span>, <span class="aref">@property</span></dd></dl><p>XHTML+RDFa also uses the Ruby Annotation module as defined in [<a class="nref" href="#ref_RUBY">RUBY</a>]:</p><dl><dt>Ruby Annotation Module</dt><dd><code>ruby, rbc, rtc, rb, rt, rp</code></dd></dl><p>There are no additional definitions required by this document type. An implementation of this document type as an <!--XML Schema is defined in<a href="xhtml11_schema.html#a_xhtml11_schema">Appendix D</a>, and as an--> XML DTD is defined in <a href="#a_xhtmlrdfadtd">Appendix B</a>.</p><!--OddPage--><h1><a id="s_metaAttributes" name="s_metaAttributes">9. Metainformation Attributes Module</a></h1><p>This section is <em>normative</em>.</p><p>The Metainformation Attributes Module defines the <a class="csref" href="mod-metaAttributes.html#col_Metainformation">Metainformation</a> attribute collection. This collection allows elements tobe annotated with metadata throughout an XHTML-family document. When this module is included in a markup language, this collection is added to the <a class="csref" href= "mod-attribute-collections.html#col_Common">Common</a> attribute collection as defined in [<a class="nref" href="#ref_XHTMLMOD">XHTMLMOD</a>].</p><h2><a id="sec_9.1." name="sec_9.1.">9.1. Datatypes</a></h2><p>Some of the attributes in this section use the following datatype:</p><table border='1' summary='Custom data types'><tr><th>Data type</th><th>Description</th></tr><tr><td id="dt_curie">CURIE</td><td>A Compact URI or <a href="#P_curie">CURIE</a>.</td></tr><tr><td id="dt_uriorcurie">URIorCURIE</td><td>A <span class="datatype"><a href="http://www.w3.org/TR/xhtml-modularization/abstraction.html#dt_URI">URI</a></span> or <a href="#P_safe_curie">safe_curie</a>.</td></tr></table><h2><a id="col_Metainformation" name="col_Metainformation">9.2. Metadata Attribute Collection</a></h2><h3><a id="sec_9.2.1." name="sec_9.2.1.">9.2.1. The about attribute</a></h3><p>This attribute specifies a <span class="datatype"><a href="#dt_uriorcurie">URIorCURIE</a></span> that indicates which resource has a specified property.</p><div class="example"><pre><meta about="http://www.example.com/" <span class='hilite'>property="dc:created"</span>>2004-03-20</meta></pre></div><h3><a id="sec_9.2.2." name="sec_9.2.2.">9.2.2. The content attribute</a></h3><p>This attribute specifies a value of type <span class="datatype"><a href="http://www.w3.org/TR/xhtml-modularization/abstraction.html#dt_CDATA">CDATA</a></span> that defines the metadata associatedwith an element. If not specified, then the metadata for an element is its content. If it is specified, and there is no <code>property</code> attribute, then the property is considered to be <code>reference</code>.</p><div class="example"><pre><meta about="http://www.example.com/" property="dc:created" <span class='hilite'>content="2004-03-20"</span>/></pre></div><h3><a id="sec_9.2.3." name="sec_9.2.3.">9.2.3. The datatype attribute</a></h3><p>This attribute defines as a <span class="datatype"><a href="#dt_curie">CURIE</a></span> the datatype of the content metadata of the element. If the attribute is not specified, then the defaultvalue is <a class="xsdref" href="#string">string</a> as defined by [<a class="nref" href="#ref_XMLSCHEMA">XMLSCHEMA</a>].</p><div class="example"><pre><meta about="http://www.example.com/" property="dc:created" <span class='hilite'>datatype="xsd:date"</span>>2004-03-20</meta></pre></div><h3><a id="sec_9.2.4." name="sec_9.2.4.">9.2.4. The instanceof attribute</a></h3><p>This attribute indicates the <code>rdf:type</code> of the associated triple(s).</p><div class="issue"><p id="s_metaAttributes_issue_6" class="issueTitle">Default instanceof value</p>What is the default value for this attribute?</div><h3><a id="sec_9.2.5." name="sec_9.2.5.">9.2.5. The property attribute</a></h3><p>This attribute specifies a space-separated list of <span class="datatype"><a href="#dt_curie">CURIE</a></span>s that indicates which property is being defined by the element.</p><div class="example"><pre><meta about="http://www.example.com/" <span class='hilite'>property="dc:creator"</span>>John Smith</meta></pre></div><p>The list of predefined values (in the XHTML namesapce) is given below. Users may extend this collection of relationships, however new values must be defined in their own vocabulary, and therelationship names must be referenced in documents as CURIEs (e.g., <code>dc:creator</code> for the Dublin Core "creator" relationship).</p><div class="example"><pre><html .... xmlns:dc="http://purl.org/dc/elements/1.1/"></pre></div><dl><dt>description</dt><dd>Gives a description of the resource.</dd><dt>generator</dt><dd>Identifies the software used to generate the resource.</dd><dt>keywords</dt><dd>Gives a comma-separated list of keywords describing the resource.</dd><dt>reference</dt><dd>The default value, gives no explicit information about the relationship with the resource.</dd><dt>robots</dt><dd>Gives advisory information intended for automated web-crawling software. This specification does not define values for this property.</dd><dt>title</dt><dd>Specifies a title for the resource.</dd></dl><p>Note that previous versions of XHTML included an <code>author</code> property; this has now been replaced with the Dublin Core <code>creator</code> property.</p><p>Note that:</p><div class="example"><pre><head> <title>My Life and Times</title></head></pre></div><p>is just a shorthand for:</p><div class="example"><pre><head> <meta property="title">My Life and Times</meta></pre></div><p>Note that the <span class="aref">@title</span> attribute is just a shorthand for a common case:</p><div class="example"><pre><a href="Jakob.html" <span class='hilite'>title="Author biography"</span>>Jakob Nielsen</a>'s Alertbox for January 11, 1998</pre></div><p>is equivalent to:</p><div class="example"><pre><h2 about="#jakob" <span class='hilite'>property="title"</span>>Author biography</h2><p><a href="Jakob.html" <span class='hilite'>id="jakob"</span>>Jakob Nielsen</a>'s Alertbox for January 11, 1998</p></pre></div><p>This allows you to specify richer, marked-up text for a title when needed.</p><h3><a id="sec_9.2.6." name="sec_9.2.6.">9.2.6. The rel attribute</a></h3><p>This attribute describes the relationship between the resource specified by <span class="aref">@about</span> (or its default value) and the resource referred to by <span class="aref">@href</span>as defined in XHTML. The type for this attribute is a space-separated list of <span class="datatype"><a href="#dt_curie">CURIE</a></span>s.</p><div class="example"><pre><link href="top.html" <span class='hilite'>rel="contents"</span> /></pre></div><p>This example defines a link to a table of contents for the current document.</p><div class="example"><pre><link href="doc.ps" <span class='hilite'>rel="alternate"</span> media="print" type="application/postscript" /></pre></div><p>This example defines a link to an alternate version of the document especially suited to printing.</p><p>Authors may use the following relationship names, listed here with their conventional interpretations.</p><p>User agents, search engines, etc. may interpret these relationships in a variety of ways. For example, user agents may provide access to linked documents through a navigation bar.</p><p>Users may extend this collection of relationships. However, extensions must be defined in their own vocabulary, and the relationship names must be referenced in documents as <span class="datatype"><a href="#dt_curie">CURIE</a></span>s (e.g., dc:creator for the Dublin Core "creator" relationship).</p><p>Note that in order to reference relationship definitions via CURIE, their prefix must be defined via an xmlns attribute somewhere suitable:</p><div class="example"><pre><html .... <span class='hilite'>xmlns:dc="http://purl.org/dc/elements/1.1/"</span>></pre></div><dl><dt>alternate</dt><dd>Designates alternate versions for the document.</dd><dt>appendix</dt><dd>Refers to a resource serving as an appendix in a collection.</dd><dt>bookmark</dt><dd>Refers to a bookmark. A bookmark is a link to a key entry point within an extended document. The <span class="aref">@title</span> attribute may be used, for example, to label the bookmark. Notethat several bookmarks may be defined for a document.</dd><dt>cite</dt><dd><p>Refers to a resource that defines a citation. In the following example, the <code>cite</code> is used to reference the book from which the quotation is taken:</p><div class="example"><p>cite as book reference</p><pre>As Gandalf the White said in <span <span class='hilite'>rel="cite"</span> about="http://www.example.com/books/the_two_towers"> The Two Towers</span>,<quote xml:lang="en">"The hospitality of your hall is somewhat lessened of late, Theoden King."</quote></pre></div><div class="example"><p>cite to reference another specification</p><pre>More information can be found in <span <span class='hilite'>property="cite"</span> about="http://www.w3.org/TR/REC-xml">[XML]</cite>.</pre></div></dd><dt>chapter</dt><dd>Refers to a resource serving as a chapter in a collection.</dd><dt>contents</dt><dd>Refers to a resource serving as a table of contents.</dd><dt>copyright</dt><dd>Refers to a copyright statement for the resource.</dd><dt>glossary</dt><dd>Refers to a resource providing a glossary of terms.</dd><dt>help</dt><dd>Refers to a resource offering help (more information, links to other sources of information, etc.)</dd><dt>icon</dt><dd>Refers to a resource that represents an icon.</dd><dt>index</dt><dd>Refers to a resource providing an index.</dd><dt>meta</dt><dd>Refers to a resource that provides metadata, for instance in RDF.</dd><dt>next</dt><dd>Refers to the next resource (after the current one) in an ordered collection.</dd><dt>p3pv1</dt><dd>Refers to a P3P Policy Reference File. See [<a class="nref" href="#ref_P3P">P3P</a>].</dd><dt>prev</dt><dd>Refers to the previous resource (before the current one) in an ordered collection.</dd><dt>role</dt><dd>Indicates the purpose of the resource. For some possible values, see [<a class="nref" href="#ref_XHTMLROLE">XHTMLROLE</a>] module.</dd><dt>section</dt><dd>Refers to a resource serving as a section in a collection.</dd><dt>subsection</dt><dd>Refers to a resource serving as a subsection in a collection.</dd><dt>start</dt><dd>Refers to the first resource in a collection of resources. A typical use case might be a collection of chapters in a book. <div class="issue"><p id="s_metaAttributes_issue_7" class="issueTitle">No end or last value</p>We have a value of "start", but no corresponding "end" value. Do we need one?</div></dd><dt>up</dt><dd>Refers to the resource "above" in a hierarchically structured set.</dd></dl><h3><a id="sec_9.2.7." name="sec_9.2.7.">9.2.7. The resource attribute</a></h3><p>This attribute takes a <span class="datatype"><a href="#dt_uriorcurie">URIorCURIE</a></span>, and can be used to define the resource referenced by a <span class="aref">@rel</span>, <span class= "aref">@rev</span>, or <span class="aref">@property</span> attribute. When provided, the value of <span class="aref">@resource</span> supercedes any value for the <span class="aref">@href</span>attribute on the same element.</p><h3><a id="sec_9.2.8." name="sec_9.2.8.">9.2.8. The rev attribute</a></h3><p>This attribute is the complement of the <span class="aref">@rel</span> attribute and describes the reverse relationship between the resource specified by the <span class="aref">@about</span>attribute (or its default value) and the resource referred to by the <span class="aref">@href</span> attribute. Its value is a space-separated list of <span class="datatype"><a href="#dt_curie">CURIE</a></span>s. For a list of relationship names, see the <span class="aref">@rel</span> attribute.</p><div class="example"><pre><link href="doc.html" <span class='hilite'>rev="contents"</span>/></pre></div><p>This example states that the current document is the table of contents for the referenced document.</p><p>An implementation of this module can be found in <a href="#a_xhtmlrdfadtd">Appendix B</a>.</p><!--OddPage--><h1><a id="a_hostlanguages" name="a_hostlanguages">A. Other Host Languages</a></h1><p><em>This section is informative.</em></p><p>While outside the scope of this specification, RDFa is intended to be extensible for use in host languages beyond XHTML 1.1. The XHTML 2 Working Group is producing a separate specification [<aclass="nref" href="#ref_XHTMLRDFA">XHTMLRDFA</a>] that defines the XHTML Modularization-compatible [<a class="nref" href="#ref_XHTMLMOD">XHTMLMOD</a>] modules to facilitate such host languages.</p><p>If a language includes <span class="aref">@xml:base</span> [<a class="nref" href="#ref_XMLBASE">XMLBASE</a>], an RDFa parser for that host language must process it, and use its value to set[base].</p><p>An example follows to show how <span class="aref">@xml:base</span> affects the subject:</p><div class="example"><pre><span <span class='hilite'>xml:base="http://internet-apps.blogspot.com/"</span>> <span about="" rel="dc:creator" href="http://www.blogger.com/profile/1109404" /> <span about="" property="dc:title" content="Internet Applications" /></span></pre></div><p>The triples generated would be as follows:</p><div class="example"><pre><http://internet-apps.blogspot.com/> dc:creator <http://www.blogger.com/profile/1109404> .<http://internet-apps.blogspot.com/> dc:title "Internet Applications" .</pre></div><!--OddPage--><h1><a id="a_xhtmlrdfadtd" name="a_xhtmlrdfadtd">B. XHTML+RDFa DTD</a></h1><p>This appendix is <em>normative</em>.</p><p>This appendix includes an implementation of the XHTML+RDFa 1.0 language as an XML DTD. It is implemented by by combining the XHTML 1.1 DTD with the XHTML Metainformation Attribute Module. This isdone by using a content model module, and then a driver module:</p><h2><a id="a_DTD_xhtml_metaAttributes_module" name="a_DTD_xhtml_metaAttributes_module">B.1. XHTML RDFa Module</a></h2><pre class="dtd"><!-- ...................................................................... --><!-- XHTML Common Attributes Module ...................................... --><!-- file: xhtml-attribs-1.mod This is XHTML-RDFa, modules to annotate XHTML family documents. Copyright 2007 W3C (MIT, ERCIM, Keio), All Rights Reserved. Revision: $Id: Overview.html,v 1.2 2007/09/18 23:48:52 jigsaw Exp $ This DTD module is identified by the PUBLIC and SYSTEM identifiers: PUBLIC "-//W3C//ENTITIES XHTML MetaAttributes 1.0//EN" SYSTEM "http://www.w3.org/MarkUp/DTD/xhtml-metaAttributes-1.mod" Revisions: (none) ....................................................................... --><!-- Common Attributes This module declares a collection of meta-information related attributes. %NS.decl.attrib; is declared in the XHTML Qname module. This file also includes declarations of "global" versions of the attributes. The global versions of the attributes are for use on elements in other namespaces. --><!ENTITY <span class="entity">% QName.datatype</span> "CDATA" ><!ENTITY <span class="entity">% QNames.datatype</span> "CDATA" ><!ENTITY <span class="entity">% about.attrib</span> "about %URI.datatype; #IMPLIED"><![%XHTML.global.attrs.prefixed;[<!ENTITY <span class="entity">% XHTML.global.about.attrib</span> "%XHTML.prefix;:about %URI.datatype; #IMPLIED">]]><!ENTITY <span class="entity">% instanceof.attrib</span> "instanceof %QName.datatype; #IMPLIED"><![%XHTML.global.attrs.prefixed;[<!ENTITY <span class="entity">% XHTML.global.instanceof.attrib</span> "%XHTML.prefix;:instanceof %QName.datatype; #IMPLIED">]]><!ENTITY <span class="entity">% property.attrib</span> "property %QNames.datatype; #IMPLIED"><![%XHTML.global.attrs.prefixed;[<!ENTITY <span class="entity">% XHTML.global.property.attrib</span> "%XHTML.prefix;:property %QNames.datatype; #IMPLIED">]]><!ENTITY <span class="entity">% resource.attrib</span> "resource %URI.datatype; #IMPLIED"><![%XHTML.global.attrs.prefixed;[<!ENTITY <span class="entity">% XHTML.global.resource.attrib</span> "%XHTML.prefix;:resource %URI.datatype; #IMPLIED">]]><!ENTITY <span class="entity">% content.attrib</span> "content CDATA #IMPLIED"><![%XHTML.global.attrs.prefixed;[<!ENTITY <span class="entity">% XHTML.global.content.attrib</span> "%XHTML.prefix;:content CDATA #IMPLIED">]]><!ENTITY <span class="entity">% datatype.attrib</span> "datatype %QName.datatype; #IMPLIED"><![%XHTML.global.attrs.prefixed;[<!ENTITY <span class="entity">% XHTML.global.datatype.attrib</span> "%XHTML.prefix;:datatype %QName.datatype; #IMPLIED">]]><!ENTITY <span class="entity">% rel.attrib</span> "rel %QNames.datatype; #IMPLIED"><![%XHTML.global.attrs.prefixed;[<!ENTITY <span class="entity">% XHTML.global.rel.attrib</span> "%XHTML.prefix;:rel %QNames.datatype; #IMPLIED">]]><!ENTITY <span class="entity">% rev.attrib</span> "rev %QNames.datatype; #IMPLIED"><![%XHTML.global.attrs.prefixed;[<!ENTITY <span class="entity">% XHTML.global.rev.attrib</span> "%XHTML.prefix;:rev %QNames.datatype; #IMPLIED">]]><!ENTITY <span class="entity">% Metainformation.extra.attrib</span> "" ><!ENTITY <span class="entity">% Metainformation.attrib</span> "%about.attrib; %content.attrib; %datatype.attrib; %instanceof.attrib; %property.attrib; %rel.attrib; %resource.attrib; %rev.attrib; %Metainformation.extra.attrib;"><!ENTITY <span class="entity">% XHTML.global.metainformation.extra.attrib</span> "" ><![%XHTML.global.attrs.prefixed;[<!ENTITY <span class="entity">% XHTML.global.metainformation.attrib</span> "%XHTML.global.about.attrib; %XHTML.global.content.attrib; %XHTML.global.datatype.attrib; %XHTML.global.instanceof.attrib; %XHTML.global.property.attrib; %XHTML.global.rel.attrib; %XHTML.global.resource.attrib; %XHTML.global.rev.attrib; %XHTML.global.metainformation.extra.attrib;">]]><!ENTITY <span class="entity">% XHTML.global.metainformation.attrib</span> "" ><!-- end of xhtml-metaAttributes-1.mod --></pre><h2><a id="a_DTD_content_model" name="a_DTD_content_model">B.2. XHTML+RDFa Content Model Module</a></h2><pre class="dtd"><!-- ....................................................................... --><!-- XHTML+RDFa Document Model Module ..................................... --><!-- file: xhtml-rdfa-model-1.mod This is XHTML+RDFa. Copyright 1998-2007 W3C (MIT, ERCIM, Keio), All Rights Reserved. Revision: $Id: Overview.html,v 1.2 2007/09/18 23:48:52 jigsaw Exp $ SMI This DTD module is identified by the PUBLIC and SYSTEM identifiers: PUBLIC "-//W3C//ENTITIES XHTML+RDFa Document Model 1.0//EN" SYSTEM "http://www.w3.org/MarkUp/DTD/xhtml-rdfa-model-1.mod" Revisions: (none) ....................................................................... --><!-- XHTML+RDFa Document Model This module describes the groupings of elements that make up common content models for XHTML elements. XHTML has three basic content models: %Inline.mix; character-level elements %Block.mix; block-like elements, eg., paragraphs and lists %Flow.mix; any block or inline elements Any parameter entities declared in this module may be used to create element content models, but the above three are considered 'global' (insofar as that term applies here). The reserved word '#PCDATA' (indicating a text string) is now included explicitly with each element declaration that is declared as mixed content, as XML requires that this token occur first in a content model specification.--><!-- Extending the Model While in some cases this module may need to be rewritten to accommodate changes to the document model, minor extensions may be accomplished by redeclaring any of the three *.extra; parameter entities to contain extension element types as follows: %Misc.extra; whose parent may be any block or inline element. %Inline.extra; whose parent may be any inline element. %Block.extra; whose parent may be any block element. If used, these parameter entities must be an OR-separated list beginning with an OR separator ("|"), eg., "| a | b | c" All block and inline *.class parameter entities not part of the *struct.class classes begin with "| " to allow for exclusion from mixes.--><!-- .............. Optional Elements in head .................. --><!ENTITY <span class="entity">% HeadOpts.mix</span> "( %script.qname; | %style.qname; | %meta.qname; | %link.qname; | %object.qname; )*"><!-- ................. Miscellaneous Elements .................. --><!-- ins and del are used to denote editing changes--><!ENTITY <span class="entity">% Edit.class</span> "| %ins.qname; | %del.qname;" ><!-- script and noscript are used to contain scripts and alternative content--><!ENTITY <span class="entity">% Script.class</span> "| %script.qname; | %noscript.qname;" ><!ENTITY <span class="entity">% Misc.extra</span> "" ><!-- These elements are neither block nor inline, and can essentially be used anywhere in the document body.--><!ENTITY <span class="entity">% Misc.class</span> "%Edit.class; %Script.class; %Misc.extra;"><!-- .................... Inline Elements ...................... --><!ENTITY <span class="entity">% InlStruct.class</span> "%br.qname; | %span.qname;" ><!ENTITY <span class="entity">% InlPhras.class</span> "| %em.qname; | %strong.qname; | %dfn.qname; | %code.qname; | %samp.qname; | %kbd.qname; | %var.qname; | %cite.qname; | %abbr.qname; | %acronym.qname; | %q.qname;" ><!ENTITY <span class="entity">% InlPres.class</span> "| %tt.qname; | %i.qname; | %b.qname; | %big.qname; | %small.qname; | %sub.qname; | %sup.qname;" ><!ENTITY <span class="entity">% I18n.class</span> "| %bdo.qname;" ><!ENTITY <span class="entity">% Anchor.class</span> "| %a.qname;" ><!ENTITY <span class="entity">% InlSpecial.class</span> "| %img.qname; | %map.qname; | %object.qname;" ><!ENTITY <span class="entity">% InlForm.class</span> "| %input.qname; | %select.qname; | %textarea.qname; | %label.qname; | %button.qname;" ><!ENTITY <span class="entity">% Inline.extra</span> "" ><!ENTITY <span class="entity">% Ruby.class</span> "| %ruby.qname;" ><!-- %Inline.class; includes all inline elements, used as a component in mixes--><!ENTITY <span class="entity">% Inline.class</span> "%InlStruct.class; %InlPhras.class; %InlPres.class; %I18n.class; %Anchor.class; %InlSpecial.class; %InlForm.class; %Ruby.class; %Inline.extra;"><!-- %InlNoRuby.class; includes all inline elements except ruby, used as a component in mixes--><!ENTITY <span class="entity">% InlNoRuby.class</span> "%InlStruct.class; %InlPhras.class; %InlPres.class; %I18n.class; %Anchor.class; %InlSpecial.class; %InlForm.class; %Inline.extra;"><!-- %NoRuby.content; includes all inlines except ruby--><!ENTITY <span class="entity">% NoRuby.content</span> "( #PCDATA | %InlNoRuby.class; %Misc.class; )*"><!-- %InlNoAnchor.class; includes all non-anchor inlines, used as a component in mixes--><!ENTITY <span class="entity">% InlNoAnchor.class</span> "%InlStruct.class; %InlPhras.class; %InlPres.class; %I18n.class; %InlSpecial.class; %InlForm.class; %Ruby.class; %Inline.extra;"><!-- %InlNoAnchor.mix; includes all non-anchor inlines--><!ENTITY <span class="entity">% InlNoAnchor.mix</span> "%InlNoAnchor.class; %Misc.class;"><!-- %Inline.mix; includes all inline elements, including %Misc.class;--><!ENTITY <span class="entity">% Inline.mix</span> "%Inline.class; %Misc.class;"><!-- ..................... Block Elements ...................... --><!-- In the HTML 4.0 DTD, heading and list elements were included in the %block; parameter entity. The %Heading.class; and %List.class; parameter entities must now be included explicitly on element declarations where desired.--><!ENTITY <span class="entity">% Heading.class</span> "%h1.qname; | %h2.qname; | %h3.qname; | %h4.qname; | %h5.qname; | %h6.qname;" ><!ENTITY <span class="entity">% List.class</span> "%ul.qname; | %ol.qname; | %dl.qname;" ><!ENTITY <span class="entity">% Table.class</span> "| %table.qname;" ><!ENTITY <span class="entity">% Form.class</span> "| %form.qname;" ><!ENTITY <span class="entity">% Fieldset.class</span> "| %fieldset.qname;" ><!ENTITY <span class="entity">% BlkStruct.class</span> "%p.qname; | %div.qname;" ><!ENTITY <span class="entity">% BlkPhras.class</span> "| %pre.qname; | %blockquote.qname; | %address.qname;" ><!ENTITY <span class="entity">% BlkPres.class</span> "| %hr.qname; " ><!ENTITY <span class="entity">% BlkSpecial.class</span> "%Table.class; %Form.class; %Fieldset.class;"><!ENTITY <span class="entity">% Block.extra</span> "" ><!-- %Block.class; includes all block elements, used as an component in mixes--><!ENTITY <span class="entity">% Block.class</span> "%BlkStruct.class; %BlkPhras.class; %BlkPres.class; %BlkSpecial.class; %Block.extra;"><!-- %Block.mix; includes all block elements plus %Misc.class;--><!ENTITY <span class="entity">% Block.mix</span> "%Heading.class; | %List.class; | %Block.class; %Misc.class;"><!-- ................ All Content Elements .................. --><!-- %Flow.mix; includes all text content, block and inline--><!ENTITY <span class="entity">% Flow.mix</span> "%Heading.class; | %List.class; | %Block.class; | %Inline.class; %Misc.class;"><!-- end of xhtml-rdfa-model-1.mod --></pre><h2><a id="a_DTD_driver" name="a_DTD_driver">B.3. XHTML+RDFa Driver Module</a></h2><pre class="dtd"><!-- ....................................................................... --><!-- XHTML 1.1 + RDFa DTD ................................................. --><!-- file: xhtml-rdfa.dtd--><!-- XHTML 1.1 + RDFa DTD This is an example markup language combining XHTML 1.1 and the RDFa modules. XHTML+RDFa Copyright 1998-2007 World Wide Web Consortium (Massachusetts Institute of Technology, European Research Consortium for Informatics and Mathematics, Keio University). All Rights Reserved. Permission to use, copy, modify and distribute the XHTML DTD and its accompanying documentation for any purpose and without fee is hereby granted in perpetuity, provided that the above copyright notice and this paragraph appear in all copies. The copyright holders make no representation about the suitability of the DTD for any purpose. It is provided "as is" without expressed or implied warranty.--><!-- This is the driver file for version 1 of the XHTML + RDFa DTD.--><!-- This is the driver file for version 1 of the XHTML + RDFa DTD. Please use this public identifier to identify it: "-//W3C//DTD XHTML+RDFa 1.0//EN"--><!ENTITY <span class="entity">% XHTML.version</span> "-//W3C//DTD XHTML+RDFa 1.0//EN" >--><!ENTITY % XHTML.version "-//W3C//DTD XHTML+RDFa 1.0//EN" ><!-- Use this URI to identify the default namespace:<!-- Use this URI to identify the default namespace: "http://www.w3.org/1999/xhtml" See the Qualified Names module for information on the use of namespace prefixes in the DTD. Note that XHTML namespace elements are not prefixed by default, but the XHTML namespace prefix is defined as "xhtml" so that other markup languages can extend this one and use the XHTML prefixed global attributes if required.--><!ENTITY <span class="entity">% NS.prefixed</span> "IGNORE" ><!ENTITY <span class="entity">% XHTML.prefix</span> "xhtml" >--><!ENTITY % NS.prefixed "IGNORE" ><!ENTITY % XHTML.prefix "xhtml" ><!-- Be sure to include prefixed global attributes - we don't need<!-- Be sure to include prefixed global attributes - we don't need them, but languages that extend XHTML 1.1 might.--><!ENTITY <span class="entity">% XHTML.global.attrs.prefixed</span> "INCLUDE" >--><!ENTITY % XHTML.global.attrs.prefixed "INCLUDE" ><!-- Reserved for use with the XLink namespace:--><!ENTITY <span class="entity">% XLINK.xmlns</span> "" ><!ENTITY <span class="entity">% XLINK.xmlns.attrib</span> "" ><!-- Reserved for use with the XLink namespace:--><!ENTITY % XLINK.xmlns "" ><!ENTITY % XLINK.xmlns.attrib "" ><!-- For example, if you are using XHTML 1.1 directly, use the public<!-- For example, if you are using XHTML 1.1 directly, use the public identifier in the DOCTYPE declaration, with the namespace declaration on the document element to identify the default namespace: <?xml version="1.0"?> <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML+RDFa 1.0//EN" "http://www.w3.org/MarkUp/DTD/xhtml-rdfa-1.dtd"> <html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en"> <?xml version="1.0"?> <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML+RDFa 1.0//EN" "http://www.w3.org/MarkUp/DTD/xhtml-rdfa-1.dtd"> <html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en"> ... </html> </html> Revisions: (none)-->--><!-- reserved for future use with document profiles --><!ENTITY <span class="entity">% XHTML.profile</span> "" ><!-- reserved for future use with document profiles --><!ENTITY % XHTML.profile "" ><!-- ensure XHTML Notations are disabled --><!ENTITY <span class="entity">% xhtml-notations.module</span> "IGNORE" ><!-- ensure XHTML Notations are disabled --><!ENTITY % xhtml-notations.module "IGNORE" ><!-- Bidirectional Text features<!-- Bidirectional Text features This feature-test entity is used to declare elements and attributes used for bidirectional text support.--><!ENTITY <span class="entity">% XHTML.bidi</span> "INCLUDE" >--><!ENTITY % XHTML.bidi "INCLUDE" ><!-- ::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::: --><!-- ::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::: --><!-- Pre-Framework Redeclaration placeholder .................... --><!-- this serves as a location to insert markup declarations<!-- Pre-Framework Redeclaration placeholder .................... --><!-- this serves as a location to insert markup declarations into the DTD prior to the framework declarations.--><!ENTITY <span class="entity">% xhtml-prefw-redecl.module</span> "IGNORE" ><!ENTITY <span class="entity">% xhtml-prefw-redecl.mod</span> "" ><![%xhtml-prefw-redecl.module;[--><!ENTITY % xhtml-prefw-redecl.module "IGNORE" ><!ENTITY % xhtml-prefw-redecl.mod "" ><![%xhtml-prefw-redecl.module;[%xhtml-prefw-redecl.mod;<!-- end of xhtml-prefw-redecl.module -->]]><!-- end of xhtml-prefw-redecl.module -->]]><!-- we need the datatypes now --><!ENTITY <span class="entity">% xhtml-datatypes.module</span> "INCLUDE" ><![%xhtml-datatypes.module;[<!ENTITY <span class="entity">% xhtml-datatypes.mod</span><!-- we need the datatypes now --><!ENTITY % xhtml-datatypes.module "INCLUDE" ><![%xhtml-datatypes.module;[<!ENTITY % xhtml-datatypes.mod PUBLIC "-//W3C//ENTITIES XHTML Datatypes 1.0//EN" "http://www.w3.org/MarkUp/DTD/xhtml-datatypes-1.mod" >%xhtml-datatypes.mod;]]> "http://www.w3.org/MarkUp/DTD/xhtml-datatypes-1.mod" >%xhtml-datatypes.mod;]]><!-- bring in the RDFa attributes cause we need them in Common --><!ENTITY <span class="entity">% xhtml-metaAttributes.module</span> "INCLUDE" ><![%xhtml-metaAttributes.module;[<!ENTITY <span class="entity">% xhtml-metaAttributes.mod</span><!-- bring in the RDFa attributes cause we need them in Common --><!ENTITY % xhtml-metaAttributes.module "INCLUDE" ><![%xhtml-metaAttributes.module;[<!ENTITY % xhtml-metaAttributes.mod PUBLIC "-//W3C//ENTITIES XHTML MetaAttributes 1.0//EN" "http://www.w3.org/MarkUp/DTD/xhtml-metaAttributes-1.mod" >%xhtml-metaAttributes.mod;]]> "http://www.w3.org/MarkUp/DTD/xhtml-metaAttributes-1.mod" >%xhtml-metaAttributes.mod;]]><!ENTITY <span class="entity">% xhtml-events.module</span> "INCLUDE" ><!ENTITY % xhtml-events.module "INCLUDE" ><!ENTITY <span class="entity">% Common.extra.attrib</span><!ENTITY % Common.extra.attrib %Metainformation.attrib;>><!-- Inline Style Module ........................................ --><!ENTITY <span class="entity">% xhtml-inlstyle.module</span> "INCLUDE" ><![%xhtml-inlstyle.module;[<!ENTITY <span class="entity">% xhtml-inlstyle.mod</span><!-- Inline Style Module ........................................ --><!ENTITY % xhtml-inlstyle.module "INCLUDE" ><![%xhtml-inlstyle.module;[<!ENTITY % xhtml-inlstyle.mod PUBLIC "-//W3C//ELEMENTS XHTML Inline Style 1.0//EN" "http://www.w3.org/MarkUp/DTD/xhtml-inlstyle-1.mod" >%xhtml-inlstyle.mod;]]> "http://www.w3.org/MarkUp/DTD/xhtml-inlstyle-1.mod" >%xhtml-inlstyle.mod;]]><!-- declare Document Model module instantiated in framework--><!ENTITY <span class="entity">% xhtml-model.mod</span><!-- declare Document Model module instantiated in framework--><!ENTITY % xhtml-model.mod PUBLIC "-//W3C//ENTITIES XHTML+RDFa Document Model 1.0//EN" "http://www.w3.org/MarkUp/DTD/xhtml-rdfa-model-1.mod" > "http://www.w3.org/MarkUp/DTD/xhtml-rdfa-model-1.mod" ><!-- Modular Framework Module (required) ......................... --><!ENTITY <span class="entity">% xhtml-framework.module</span> "INCLUDE" ><![%xhtml-framework.module;[<!ENTITY <span class="entity">% xhtml-framework.mod</span><!-- Modular Framework Module (required) ......................... --><!ENTITY % xhtml-framework.module "INCLUDE" ><![%xhtml-framework.module;[<!ENTITY % xhtml-framework.mod PUBLIC "-//W3C//ENTITIES XHTML Modular Framework 1.0//EN" "http://www.w3.org/MarkUp/DTD/xhtml-framework-1.mod" >%xhtml-framework.mod;]]> "http://www.w3.org/MarkUp/DTD/xhtml-framework-1.mod" >%xhtml-framework.mod;]]><!-- Post-Framework Redeclaration placeholder ................... --><!-- this serves as a location to insert markup declarations<!-- Post-Framework Redeclaration placeholder ................... --><!-- this serves as a location to insert markup declarations into the DTD following the framework declarations.--><!ENTITY <span class="entity">% xhtml-postfw-redecl.module</span> "IGNORE" ><!ENTITY <span class="entity">% xhtml-postfw-redecl.mod</span> ""><![%xhtml-postfw-redecl.module;[--><!ENTITY % xhtml-postfw-redecl.module "IGNORE" ><!ENTITY % xhtml-postfw-redecl.mod ""><![%xhtml-postfw-redecl.module;[%xhtml-postfw-redecl.mod;<!-- end of xhtml-postfw-redecl.module -->]]><!-- end of xhtml-postfw-redecl.module -->]]><!-- Text Module (Required) ..................................... --><!ENTITY <span class="entity">% xhtml-text.module</span> "INCLUDE" ><![%xhtml-text.module;[<!ENTITY <span class="entity">% xhtml-text.mod</span><!-- Text Module (Required) ..................................... --><!ENTITY % xhtml-text.module "INCLUDE" ><![%xhtml-text.module;[<!ENTITY % xhtml-text.mod PUBLIC "-//W3C//ELEMENTS XHTML Text 1.0//EN" "http://www.w3.org/MarkUp/DTD/xhtml-text-1.mod" >%xhtml-text.mod;]]> "http://www.w3.org/MarkUp/DTD/xhtml-text-1.mod" >%xhtml-text.mod;]]><!-- Hypertext Module (required) ................................. --><!ENTITY <span class="entity">% a.attlist</span> "IGNORE" ><!ENTITY <span class="entity">% xhtml-hypertext.module</span> "INCLUDE" ><![%xhtml-hypertext.module;[<!ENTITY <span class="entity">% xhtml-hypertext.mod</span><!-- Hypertext Module (required) ................................. --><!ENTITY % a.attlist "IGNORE" ><!ENTITY % xhtml-hypertext.module "INCLUDE" ><![%xhtml-hypertext.module;[<!ENTITY % xhtml-hypertext.mod PUBLIC "-//W3C//ELEMENTS XHTML Hypertext 1.0//EN" "http://www.w3.org/MarkUp/DTD/xhtml-hypertext-1.mod" >%xhtml-hypertext.mod;]]><!ATTLIST %a.qname; "http://www.w3.org/MarkUp/DTD/xhtml-hypertext-1.mod" >%xhtml-hypertext.mod;]]><!ATTLIST %a.qname; %Common.attrib; charset %Charset.datatype; #IMPLIED type %ContentType.datatype; #IMPLIED accesskey %Character.datatype; #IMPLIED tabindex %Number.datatype; #IMPLIED>><!-- Lists Module (required) .................................... --><!ENTITY <span class="entity">% xhtml-list.module</span> "INCLUDE" ><![%xhtml-list.module;[<!ENTITY <span class="entity">% xhtml-list.mod</span><!-- Lists Module (required) .................................... --><!ENTITY % xhtml-list.module "INCLUDE" ><![%xhtml-list.module;[<!ENTITY % xhtml-list.mod PUBLIC "-//W3C//ELEMENTS XHTML Lists 1.0//EN" "http://www.w3.org/MarkUp/DTD/xhtml-list-1.mod" >%xhtml-list.mod;]]> "http://www.w3.org/MarkUp/DTD/xhtml-list-1.mod" >%xhtml-list.mod;]]><!-- ::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::: --><!-- ::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::: --><!-- Edit Module ................................................ --><!ENTITY <span class="entity">% xhtml-edit.module</span> "INCLUDE" ><![%xhtml-edit.module;[<!ENTITY <span class="entity">% xhtml-edit.mod</span><!-- Edit Module ................................................ --><!ENTITY % xhtml-edit.module "INCLUDE" ><![%xhtml-edit.module;[<!ENTITY % xhtml-edit.mod PUBLIC "-//W3C//ELEMENTS XHTML Editing Elements 1.0//EN" "http://www.w3.org/MarkUp/DTD/xhtml-edit-1.mod" >%xhtml-edit.mod;]]> "http://www.w3.org/MarkUp/DTD/xhtml-edit-1.mod" >%xhtml-edit.mod;]]><!-- BIDI Override Module ....................................... --><!ENTITY <span class="entity">% xhtml-bdo.module</span> "%XHTML.bidi;" ><![%xhtml-bdo.module;[<!ENTITY <span class="entity">% xhtml-bdo.mod</span><!-- BIDI Override Module ....................................... --><!ENTITY % xhtml-bdo.module "%XHTML.bidi;" ><![%xhtml-bdo.module;[<!ENTITY % xhtml-bdo.mod PUBLIC "-//W3C//ELEMENTS XHTML BIDI Override Element 1.0//EN" "http://www.w3.org/MarkUp/DTD/xhtml-bdo-1.mod" >%xhtml-bdo.mod;]]> "http://www.w3.org/MarkUp/DTD/xhtml-bdo-1.mod" >%xhtml-bdo.mod;]]><!-- Ruby Module ................................................ --><!ENTITY <span class="entity">% Ruby.common.attlists</span> "INCLUDE" ><!ENTITY <span class="entity">% Ruby.common.attrib</span> "%Common.attrib;" ><!ENTITY <span class="entity">% xhtml-ruby.module</span> "INCLUDE" ><![%xhtml-ruby.module;[<!ENTITY <span class="entity">% xhtml-ruby.mod</span><!-- Ruby Module ................................................ --><!ENTITY % Ruby.common.attlists "INCLUDE" ><!ENTITY % Ruby.common.attrib "%Common.attrib;" ><!ENTITY % xhtml-ruby.module "INCLUDE" ><![%xhtml-ruby.module;[<!ENTITY % xhtml-ruby.mod PUBLIC "-//W3C//ELEMENTS XHTML Ruby 1.0//EN" "http://www.w3.org/TR/ruby/xhtml-ruby-1.mod" >%xhtml-ruby.mod;]]> "http://www.w3.org/TR/ruby/xhtml-ruby-1.mod" >%xhtml-ruby.mod;]]><!-- Presentation Module ........................................ --><!ENTITY <span class="entity">% xhtml-pres.module</span> "INCLUDE" ><![%xhtml-pres.module;[<!ENTITY <span class="entity">% xhtml-pres.mod</span><!-- Presentation Module ........................................ --><!ENTITY % xhtml-pres.module "INCLUDE" ><![%xhtml-pres.module;[<!ENTITY % xhtml-pres.mod PUBLIC "-//W3C//ELEMENTS XHTML Presentation 1.0//EN" "http://www.w3.org/MarkUp/DTD/xhtml-pres-1.mod" >%xhtml-pres.mod;]]> "http://www.w3.org/MarkUp/DTD/xhtml-pres-1.mod" >%xhtml-pres.mod;]]><!-- Document Metainformation Module ............................ --><!ENTITY <span class="entity">% xhtml-meta.module</span> "INCLUDE" ><![%xhtml-meta.module;[<!ENTITY <span class="entity">% xhtml-meta.mod</span><!-- Document Metainformation Module ............................ --><!ENTITY % xhtml-meta.module "INCLUDE" ><![%xhtml-meta.module;[<!ENTITY % xhtml-meta.mod PUBLIC "-//W3C//ELEMENTS XHTML Metainformation 1.0//EN" "http://www.w3.org/MarkUp/DTD/xhtml-meta-1.mod" >%xhtml-meta.mod;]]> "http://www.w3.org/MarkUp/DTD/xhtml-meta-1.mod" >%xhtml-meta.mod;]]><!-- Base Element Module ........................................ --><!ENTITY <span class="entity">% xhtml-base.module</span> "INCLUDE" ><![%xhtml-base.module;[<!ENTITY <span class="entity">% xhtml-base.mod</span><!-- Base Element Module ........................................ --><!ENTITY % xhtml-base.module "INCLUDE" ><![%xhtml-base.module;[<!ENTITY % xhtml-base.mod PUBLIC "-//W3C//ELEMENTS XHTML Base Element 1.0//EN" "http://www.w3.org/MarkUp/DTD/xhtml-base-1.mod" >%xhtml-base.mod;]]> "http://www.w3.org/MarkUp/DTD/xhtml-base-1.mod" >%xhtml-base.mod;]]><!-- Scripting Module ........................................... --><!ENTITY <span class="entity">% xhtml-script.module</span> "INCLUDE" ><![%xhtml-script.module;[<!ENTITY <span class="entity">% xhtml-script.mod</span><!-- Scripting Module ........................................... --><!ENTITY % xhtml-script.module "INCLUDE" ><![%xhtml-script.module;[<!ENTITY % xhtml-script.mod PUBLIC "-//W3C//ELEMENTS XHTML Scripting 1.0//EN" "http://www.w3.org/MarkUp/DTD/xhtml-script-1.mod" >%xhtml-script.mod;]]> "http://www.w3.org/MarkUp/DTD/xhtml-script-1.mod" >%xhtml-script.mod;]]><!-- Style Sheets Module ......................................... --><!ENTITY <span class="entity">% xhtml-style.module</span> "INCLUDE" ><![%xhtml-style.module;[<!ENTITY <span class="entity">% xhtml-style.mod</span><!-- Style Sheets Module ......................................... --><!ENTITY % xhtml-style.module "INCLUDE" ><![%xhtml-style.module;[<!ENTITY % xhtml-style.mod PUBLIC "-//W3C//ELEMENTS XHTML Style Sheets 1.0//EN" "http://www.w3.org/MarkUp/DTD/xhtml-style-1.mod" >%xhtml-style.mod;]]> "http://www.w3.org/MarkUp/DTD/xhtml-style-1.mod" >%xhtml-style.mod;]]><!-- Image Module ............................................... --><!ENTITY <span class="entity">% xhtml-image.module</span> "INCLUDE" ><![%xhtml-image.module;[<!ENTITY <span class="entity">% xhtml-image.mod</span><!-- Image Module ............................................... --><!ENTITY % xhtml-image.module "INCLUDE" ><![%xhtml-image.module;[<!ENTITY % xhtml-image.mod PUBLIC "-//W3C//ELEMENTS XHTML Images 1.0//EN" "http://www.w3.org/MarkUp/DTD/xhtml-image-1.mod" >%xhtml-image.mod;]]> "http://www.w3.org/MarkUp/DTD/xhtml-image-1.mod" >%xhtml-image.mod;]]><!-- Client-side Image Map Module ............................... --><!ENTITY <span class="entity">% area.attlist</span> "IGNORE" ><!ENTITY <span class="entity">% xhtml-csismap.module</span> "INCLUDE" ><![%xhtml-csismap.module;[<!ENTITY <span class="entity">% xhtml-csismap.mod</span><!-- Client-side Image Map Module ............................... --><!ENTITY % area.attlist "IGNORE" ><!ENTITY % xhtml-csismap.module "INCLUDE" ><![%xhtml-csismap.module;[<!ENTITY % xhtml-csismap.mod PUBLIC "-//W3C//ELEMENTS XHTML Client-side Image Maps 1.0//EN" "http://www.w3.org/MarkUp/DTD/xhtml-csismap-1.mod" >%xhtml-csismap.mod;]]><!ATTLIST %area.qname; "http://www.w3.org/MarkUp/DTD/xhtml-csismap-1.mod" >%xhtml-csismap.mod;]]><!ATTLIST %area.qname; %Common.attrib; shape %Shape.datatype; 'rect' coords %Coords.datatype; #IMPLIED nohref ( nohref ) #IMPLIED alt %Text.datatype; #REQUIRED tabindex %Number.datatype; #IMPLIED accesskey %Character.datatype; #IMPLIED>><!-- Server-side Image Map Module ............................... --><!ENTITY <span class="entity">% xhtml-ssismap.module</span> "INCLUDE" ><![%xhtml-ssismap.module;[<!ENTITY <span class="entity">% xhtml-ssismap.mod</span><!-- Server-side Image Map Module ............................... --><!ENTITY % xhtml-ssismap.module "INCLUDE" ><![%xhtml-ssismap.module;[<!ENTITY % xhtml-ssismap.mod PUBLIC "-//W3C//ELEMENTS XHTML Server-side Image Maps 1.0//EN" "http://www.w3.org/MarkUp/DTD/xhtml-ssismap-1.mod" >%xhtml-ssismap.mod;]]> "http://www.w3.org/MarkUp/DTD/xhtml-ssismap-1.mod" >%xhtml-ssismap.mod;]]><!-- Param Element Module ....................................... --><!ENTITY <span class="entity">% xhtml-param.module</span> "INCLUDE" ><![%xhtml-param.module;[<!ENTITY <span class="entity">% xhtml-param.mod</span><!-- Param Element Module ....................................... --><!ENTITY % xhtml-param.module "INCLUDE" ><![%xhtml-param.module;[<!ENTITY % xhtml-param.mod PUBLIC "-//W3C//ELEMENTS XHTML Param Element 1.0//EN" "http://www.w3.org/MarkUp/DTD/xhtml-param-1.mod" >%xhtml-param.mod;]]> "http://www.w3.org/MarkUp/DTD/xhtml-param-1.mod" >%xhtml-param.mod;]]><!-- Embedded Object Module ..................................... --><!ENTITY <span class="entity">% xhtml-object.module</span> "INCLUDE" ><![%xhtml-object.module;[<!ENTITY <span class="entity">% xhtml-object.mod</span><!-- Embedded Object Module ..................................... --><!ENTITY % xhtml-object.module "INCLUDE" ><![%xhtml-object.module;[<!ENTITY % xhtml-object.mod PUBLIC "-//W3C//ELEMENTS XHTML Embedded Object 1.0//EN" "http://www.w3.org/MarkUp/DTD/xhtml-object-1.mod" >%xhtml-object.mod;]]> "http://www.w3.org/MarkUp/DTD/xhtml-object-1.mod" >%xhtml-object.mod;]]><!-- Tables Module ............................................... --><!ENTITY <span class="entity">% xhtml-table.module</span> "INCLUDE" ><![%xhtml-table.module;[<!ENTITY <span class="entity">% xhtml-table.mod</span><!-- Tables Module ............................................... --><!ENTITY % xhtml-table.module "INCLUDE" ><![%xhtml-table.module;[<!ENTITY % xhtml-table.mod PUBLIC "-//W3C//ELEMENTS XHTML Tables 1.0//EN" "http://www.w3.org/MarkUp/DTD/xhtml-table-1.mod" >%xhtml-table.mod;]]> "http://www.w3.org/MarkUp/DTD/xhtml-table-1.mod" >%xhtml-table.mod;]]><!-- Forms Module ............................................... --><!ENTITY <span class="entity">% xhtml-form.module</span> "INCLUDE" ><![%xhtml-form.module;[<!ENTITY <span class="entity">% xhtml-form.mod</span><!-- Forms Module ............................................... --><!ENTITY % xhtml-form.module "INCLUDE" ><![%xhtml-form.module;[<!ENTITY % xhtml-form.mod PUBLIC "-//W3C//ELEMENTS XHTML Forms 1.0//EN" "http://www.w3.org/MarkUp/DTD/xhtml-form-1.mod" >%xhtml-form.mod;]]> "http://www.w3.org/MarkUp/DTD/xhtml-form-1.mod" >%xhtml-form.mod;]]><!-- Target Attribute Module .................................... --><!ENTITY <span class="entity">% xhtml-target.module</span> "INCLUDE" ><![%xhtml-target.module;[<!ENTITY <span class="entity">% xhtml-target.mod</span><!-- Target Attribute Module .................................... --><!ENTITY % xhtml-target.module "INCLUDE" ><![%xhtml-target.module;[<!ENTITY % xhtml-target.mod PUBLIC "-//W3C//ELEMENTS XHTML Target 1.0//EN" "http://www.w3.org/MarkUp/DTD/xhtml-target-1.mod" >%xhtml-target.mod;]]> "http://www.w3.org/MarkUp/DTD/xhtml-target-1.mod" >%xhtml-target.mod;]]><!-- Legacy Markup ............................................... --><!ENTITY <span class="entity">% xhtml-legacy.module</span> "IGNORE" ><![%xhtml-legacy.module;[<!ENTITY <span class="entity">% xhtml-legacy.mod</span><!-- Legacy Markup ............................................... --><!ENTITY % xhtml-legacy.module "IGNORE" ><![%xhtml-legacy.module;[<!ENTITY % xhtml-legacy.mod PUBLIC "-//W3C//ELEMENTS XHTML Legacy Markup 1.0//EN" "http://www.w3.org/MarkUp/DTD/xhtml-legacy-1.mod" >%xhtml-legacy.mod;]]> "http://www.w3.org/MarkUp/DTD/xhtml-legacy-1.mod" >%xhtml-legacy.mod;]]><!-- Document Structure Module (required) ....................... --><!ENTITY <span class="entity">% head.attlist</span> "IGNORE" ><!ENTITY <span class="entity">% xhtml-struct.module</span> "INCLUDE" ><![%xhtml-struct.module;[<!ENTITY <span class="entity">% xhtml-struct.mod</span><!-- Document Structure Module (required) ....................... --><!ENTITY % head.attlist "IGNORE" ><!ENTITY % xhtml-struct.module "INCLUDE" ><![%xhtml-struct.module;[<!ENTITY % xhtml-struct.mod PUBLIC "-//W3C//ELEMENTS XHTML Document Structure 1.0//EN" "http://www.w3.org/MarkUp/DTD/xhtml-struct-1.mod" >%xhtml-struct.mod;]]><!ENTITY <span class="entity">% profile.attrib</span> "http://www.w3.org/MarkUp/DTD/xhtml-struct-1.mod" >%xhtml-struct.mod;]]><!ENTITY % profile.attrib "profile %URI.datatype; '%XHTML.profile;'"><!ATTLIST %head.qname;><!ATTLIST %head.qname; %Common.attrib; %profile.attrib;>><!-- end of XHTML-RDFa DTD ................................................ --><!-- ....................................................................... --></pre><h2><a id="a_xhtml11_catalog" name="a_xhtml11_catalog">B.4. SGML Open Catalog Entry for XHTML+RDFa</a></h2><p>This section contains the SGML Open Catalog-format definition [<a href="references.html#ref_catalog">CATALOG</a>] of the public identifiers for XHTML+RDFa 1.0.</p><pre class="dtd">-- .......................................................................... ---- File catalog ............................................................ ---- XHTML+RDFa Catalog Data File Revision: $Revision: 1.2 $ See "Entity Management", SGML Open Technical Resolution 9401 for detailed information on supplying and using catalog data. This document is available from OASIS at URL: <http://www.oasis-open.org/html/tr9401.html>---- .......................................................................... ---- SGML declaration associated with XHTML .................................. --OVERRIDE YESSGMLDECL "xml1.dcl"-- :::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::: ---- XHTML+RDFa modules .............................................. --PUBLIC "-//W3C//DTD XHTML+RDFa 1.0//EN" "xhtml-rdfa-1.dtd"PUBLIC "-//W3C//ENTITIES XHTML+RDFa Document Model 1.0//EN" "xhtml-rdfa-model-1.mod"PUBLIC "-//W3C//ENTITIES XHTML MetaAttributes 1.0//EN" "xhtml-metaAttributes-1.mod"-- End of catalog data ..................................................... ---- .......................................................................... --</pre><!--OddPage--><h1><a id="a_references" name="a_references">C. References</a></h1><h2><a id="sec_C.1." name="sec_C.1.">C.1. Related Specifications</a></h2><p><i>This section is normative.</i></p><dl><dt><a id="ref_HTML4" name="ref_HTML4" class="normref">HTML4</a></dt><dd>"<cite><a href="http://www.w3.org/TR/1999/REC-html401-19991224">HTML 4.01 Specification</a></cite>", W3C Recommendation, D. Raggett <i lang="la" xml:lang="la">et al.</i>, <i><abbr title="editors">eds.</abbr></i>, 24 December 1999.<br />Available at: http://www.w3.org/TR/1999/REC-html401-19991224</dd><dt><a id="ref_IRI" name="ref_IRI" class="normref">IRI</a></dt><dd>"<cite><a href="http://www.ietf.org/rfc/rfc3987.txt">Internationalized Resource Identifiers (IRI)</a></cite>", RFC 3987, M.Duerst, M. Suignard January 2005.<br />Available at: http://www.ietf.org/rfc/rfc3987.txt</dd><dt><a id="ref_RFC2119" name="ref_RFC2119" class="normref">[RFC2119]</a></dt><dd>"<cite><a href="http://www.rfc-editor.org/rfc/rfc2119.txt">Key words for use in RFCs to indicate requirement levels</a></cite>", RFC 2119, S. Bradner, March 1997.<br /> Available at: http://www.rfc-editor.org/rfc/rfc2119.txt</dd><dt><a id="ref_ruby" class="normref">[RUBY]</a></dt><dd><cite><a href="http://www.w3.org/TR/2001/REC-ruby-20010531">Ruby Annotation</a></cite>, W3C Recommendation, Marcin Sawicki, et al., 31 May 2001.<br /> See: http://www.w3.org/TR/2001/REC-ruby-20010531</dd><dt class="label"><a name="ref_XHTML11" id="ref_XHTML11"></a>XHTML 1.1</dt><dd>"<cite><a href="http://www.w3.org/TR/2001/REC-xhtml11-20010531/">XHTML 1.1 - Module-based XHTML</a></cite>", W3C Recommendation, M. Altheim, S. McCarron, 31 May 2001.<br />Available at: <a href="http://www.w3.org/TR/2001/REC-xhtml11-20010531/">http://www.w3.org/TR/2001/REC-xhtml11-20010531/</a>.</dd><dt><a id="ref_XMLBASE" name="ref_XMLBASE" class="normref">XMLBASE</a></dt><dd>"<cite><a href="http://www.w3.org/TR/2001/REC-xmlbase-20010627/">XML Base</a></cite>", W3C Recommendation, J. Marsh, <i><abbr title="editor">ed.</abbr></i>, 27 June 2001.<br />Available at: http://www.w3.org/TR/2001/REC-xmlbase-20010627/</dd><dt class="label"><a name="XML-LANG" id="XML-LANG"></a>XML-LANG</dt><dd>"<cite><a href="http://www.w3.org/TR/2004/REC-xml-20040204">Extensible Markup Language (XML) 1.0 (Third Edition)</a></cite>", W3C Recommendation, T. Bray <i lang="la" xml:lang="la">et al.</i>,<i><abbr title="editors">eds.</abbr></i>, 4 February 2004.<br />Available at: http://www.w3.org/TR/2004/REC-xml-20040204</dd><dt><a id="ref_xmlschema" name="ref_xmlschema" class="normref">[XMLSCHEMA]</a></dt><dd>"<cite><a href="http://www.w3.org/TR/2004/REC-xmlschema-1-20041028/">XML Schema Part 1: Structures Second Edition</a></cite>", W3C Recommendation, H. S. Thompson <i lang="la" xml:lang="la">etal.</i>, <i><abbr title="editors">eds.</abbr></i>, 28 October 2004.<br />Available at: http://www.w3.org/TR/2004/REC-xmlschema-1-20041028/<br />See also "<cite><a href="http://www.w3.org/TR/2004/REC-xmlschema-2-20041028/">XML Schema Part 2: Datatypes Second Edition</a></cite>", available at:http://www.w3.org/TR/2004/REC-xmlschema-2-20041028/</dd></dl><h2><a id="sec_C.2." name="sec_C.2.">C.2. Related Activities</a></h2><p><i>This section is informative.</i></p><dl><dt><a id="ref_CATALOG" class="ref">[CATALOG]</a></dt><dd><cite><a href="http://www.oasis-open.org/html/a401.htm">Entity Management: OASIS Technical Resolution 9401:1997 (Amendment 2 to TR 9401)</a></cite>, Paul Grosso, Chair, Entity ManagementSubcommittee, SGML Open, 10 September 1997.<br /> See: http://www.oasis-open.org/html/a401.htm</dd><dt class="label"><a name="DC" id="DC"></a>DC</dt><dd>Dublin Core Metadata Initiative (DCMI) (See <a href="http://dublincore.org/">http://dublincore.org/</a>.)</dd><dt class="label"><a name="FOAF-PROJECT" id="FOAF-PROJECT"></a>FOAF-PROJECT</dt><dd>The FOAF Project (See <a href="http://www.foaf-project.org">http://www.foaf-project.org</a>.)</dd><dt class="label"><a name="N-TRIPLES" id="N-TRIPLES"></a>N-TRIPLES</dt><dd>RDF Test Cases, N-Triples (See <a href="http://www.w3.org/TR/rdf-testcases/#ntriples">http://www.w3.org/TR/rdf-testcases/#ntriples</a>.)</dd><dt class="label"><a name="N3-PRIMER" id="N3-PRIMER"></a>N3-PRIMER</dt><dd>N3 Primer (See <a href="http://www.w3.org/2000/10/swap/Primer">http://www.w3.org/2000/10/swap/Primer</a>.)</dd><dt class="label"><a name="ref_RDFaPRIMER" id="ref_RDFaPRIMER"></a>RDFa Primer</dt><dd>RDFa Primer 1.0 - Embedding Structured Data in Web Pages (see <a href="http://www.w3.org/2006/07/SWD/RDFa/primer">http://www.w3.org/2006/07/SWD/RDFa/primer</a>.)</dd><dt class="label"><a name="RDF-CONCEPTS" id="RDF-CONCEPTS"></a>RDF-CONCEPTS</dt><dd>Resource Description Framework (RDF): Concepts and Abstract Syntax (See <a href="http://www.w3.org/TR/rdf-concepts/">http://www.w3.org/TR/rdf-concepts/</a>.)</dd><dt class="label"><a name="ref_RDF-PRIMER" id="rdf_RDF-PRIMER"></a>RDF-PRIMER</dt><dd>RDF Primer (See <a href="http://www.w3.org/TR/rdf-primer/">http://www.w3.org/TR/rdf-primer/</a>.)</dd><dt class="label"><a name="RDF-SYNTAX" id="RDF-SYNTAX"></a>RDF-SYNTAX</dt><dd>RDF/XML Syntax and Grammar (See <a href="http://www.w3.org/TR/rdf-syntax-grammar/">http://www.w3.org/TR/rdf-syntax-grammar/</a>.)</dd><dt class="label"><a name="RDFTESTS-DATATYPES-TEST001" id="RDFTESTS-DATATYPES-TEST001"></a>RDFTESTS-DATATYPES-TEST001</dt><dd>datatypes/test001.nt (See <a href="http://www.w3.org/2000/10/rdf-tests/rdfcore/datatypes/test001.nt">http://www.w3.org/2000/10/rdf-tests/rdfcore/datatypes/test001.nt</a>.)</dd><dt class="label"><a name="RDFTESTS-RDFMS-XMLLANG-TEST006" id="RDFTESTS-RDFMS-XMLLANG-TEST006"></a>RDFTESTS-RDFMS-XMLLANG-TEST006</dt><dd>rdfms-xmllang/test006.nt (See <a href="http://www.w3.org/2000/10/rdf-tests/rdfcore/rdfms-xmllang/test006.nt">http://www.w3.org/2000/10/rdf-tests/rdfcore/rdfms-xmllang/test006.nt</a>.)</dd><dt class="label"><a name="RELAXNG" id="RELAXNG"></a>RELAXNG</dt><dd>RELAX NG Home Page (See <a href="http://www.relaxng.org/">http://www.relaxng.org/</a>.)</dd><dt class="label"><a name="SWD-WG" id="SWD-WG"></a>SWD-WG</dt><dd>Semantic Web Best Deployment Working Group (See <a href="http://www.w3.org/2006/07/SWD/">http://www.w3.org/2006/07/SWD/</a>.)</dd><dt class="label"><a name="RDFHTML" id="RDFHTML"></a>RDFHTML</dt><dd>RDF-in-HTML Task Force (See <a href="http://w3.org/2001/sw/BestPractices/HTML/">http://w3.org/2001/sw/BestPractices/HTML/</a>.)</dd><dt class="label"><a name="SWBPD-WG" id="SWBPD-WG"></a>SWBPD-WG</dt><dd>Semantic Web Best Practices and Deployment Working Group (See <a href="http://w3.org/2001/sw/BestPractices/">http://w3.org/2001/sw/BestPractices/</a>.)</dd><dt class="label"><a name="XHTML2-WG" id="XHTML2-WG"></a>XHTML2-WG</dt><dd>XHTML 2 Working Group (See <a href="http://w3.org/MarkUp/Group/">http://w3.org/MarkUp/Group/</a>.)</dd><dt class="label"><a name="CURIE" id="CURIE"></a>CURIE</dt><dd>CURIEs (See <a href="http://w3.org/TR/curie">http://w3.org/TR/curie</a>.)</dd></dl><!--OddPage--><h1><a id="a_history" name="a_history">D. Change History</a></h1><p><em>This section is informative.</em></p><p>2007-09-04: Migrated to XHTML 2 Working Group Publication System. Converted to a format that is consistent with REC-Track documents. Updated to reflect current processing model. Added normativedefinition of CURIEs. Started updating prose to be consistent with current task force agremeents. [ShaneMcCarron], [StevenPemberton], [MarkBirbeck]</p><p>2007-04-06: fixed some of the language to talk about "structure" rather than metadata. Added note regarding space-separated values in predicate-denoting attributes. [BenAdida]</p><p>2006-01-16: made the use of CURIE type for <span class="aref">@rel</span>, <span class="aref">@rev</span>, <span class="aref">@property</span> consistent across document (particularly section 2.4was erroneous). [BenAdida]</p><!--OddPage--><h1><a id="a_acks" name="a_acks">E. Acknowledgments</a></h1><p><em>This section is informative.</em></p><p><em>This section is informative.</em></p><p>At the time of publication, the participants in the W3C XHTML 2 Working Group were:</p></body></html><!-- end of XHTML-RDFa DTD ................................................ --><!-- ....................................................................... -->