ERDF
From GetSemantic
eRDF[1] is a syntax of RDF and that can be embedded into XHTML or HTML by using common idioms and attributes. It is a subset of RDF too, since it does not allow external URIs to be subjects in an RDF triple.
No new elements or attributes have been invented and the usages of the HTML attributes are within normal bounds. It is designed to work with CSS and other HTML support technologies.
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[edit] Thinking in eRDF
The principles of eRDF are as follows - but see the eRDF spec for a more detailed explanation.
[edit] @id, @src, and @href
- @ids create a URI within an html document.
- URIs can be used for representing things.
- Give each thing you are describing an @id.
- @href and @src also contain URI's, which can also be used to represent things
- the URL of the current document is also a URI, and can represent a thing that can be described within the document.
[edit] @class
@class describes visible content (@title, if it exists, and inner text or img/@src if it doesn't)
eRDF uses a special convention for class names so as not to get them mixed up with 'normal' class names used for css/javascript/microformats/etc. eRDF class names take the form:prefix-term
prefix stands for a schema reference by a <link rel="schema.prefix" href="http://example.com/schema/url"/> in the head element. eg:
<link rel="schema.foaf" href="http://xmlns.com/foaf/0.1/"/>
If the class name begins with a hyphen (eg: -foaf-Person), it means that this thing (represented by the nearest @id) is this type of thing (eg: a person, as defined in the foaf schema).
If the class name doesn't begin with a hyphen (eg: dc-title), it is the name of the property of the thing.
NB: If the prefix 'foaf' isn't defined by a link in the head, then an eRDF processor will ignore it.
[edit] @rel and @rev
- @rel and @rev relate the URI of the thing being described with the URI in the @href of the anchor element.
- @rel and @rev use the same conventions as @class (described above).
- an eRDF-style @rel value indicates the relationship of the @href to the @id
- an eRDF-style @rev value indicates the relationship of the @id to the @href
[edit] @rel
<div id="me">
I kissed <a rel="kiss-kissed" href="http://example.com/#her">her</a>
</div>
[edit] @rev
<div id="me">
<a rev="kiss-kissed" href="http://example.com/#her">She</a> kissed me!
</div>
( using the kiss vocabulary)
[edit] Sample Snippets
- Personal Information in eRDF
- Movies I've Watched (how to mark them up in eRDF)
- A Bulletin Board Thread in eRDF
- A Blog Post in eRDF
- Art Object in eRDF snippet
[edit] Tools for eRDF
- eRDF scraper for Simile's PiggyBank
- ARC PHP classes, includes eRDF parser
- Raptor RDF parser toolkit, supports eRDF
- an xslt stylesheet to transform eRDF in xhtml to RDF/XML
- eRDF greasemonkey script to detect, and optionally parse eRDF in the page (looks for the eRDF profile on the head element)
- Triplr_operator_userscript
- javascript eRDF parser
- PHP5 eRDF parser
- eRDF-T - a PHP eRDF-based templating system
[edit] Web Services that extract RDF from eRDF
[edit] eRDF in the Wild
- More Than Seven
- Ian Davis's homepage
- SemWebDev
- Tom Morris' Blog
- PigleT's site
- Wadhurst Independent Photographers
- Dan Connolly
- Digital Web Contributors - each contributor is marked up with eRDF
(add any eRDF pages you find)
[edit] More information
- RDF For The Rest Of Us by Keith Alexander
