This version: January 2, 2001
Latest Version: January 2, 2001
Previous Version: January 2, 2001
Note: you are looking at the
actual XML Resource Directory for the
This document defines a Resource Directory Description Language. A Resource Directory serves as a text description of a resource identifier such as an XML Namespace  and includes links to resources associated with the namespace such as schemata, stylesheets and/or other resources associated with the namespace URI. A Resource Directory Description is designed to be suitable for service as the body of a resource returned by deferencing a URI serving as an XML Namespace name.
The Resource Directory Description Language is an extension of XHTML Basic 1.0 with a new element named "resource". The resource element serves as an XLink to the referenced resource.
This document defines the syntax and semantics of the Resource Directory Description Language, and also serves as a Resource Directory Description for the namespace
The Resource Directory Description 1.0 DTD has been produced as an extension of XHTML Basic 1.0 .
The Resource Directory Description Language was initially proposed and specified after discussion on the XML-DEV mailing list.
The resource element is qualified with the namespace URI
The resource element represents a simple xlink with an additional attribute content-type which
provides for an optional content type specifiers. The
content-type attribute is not namespace qualified.
rddl:resource element may be placed within the html
body. The %Flow.mix entity has been
redefined to contain
rddl:resource so it rougly may be placed anywhere a
p tag may be placed.
rddl:resource element itself uses the
%Flow.mix content model, and SHOULD have content
which describes the associated resource.
<!ELEMENT rddl:resource (#PCDATA | %Flow.mix;)*> <!ATTLIST rddl:resource %Common.attrib; xmlns:rddl CDATA #FIXED 'http://www.openhealth.org/RDDL/' xlink:type (simple|arc|locator|resource) "simple" xlink:role CDATA 'http://www.openhealth.org/RDDL/' xlink:arcrole CDATA #IMPLIED xlink:title CDATA #IMPLIED xlink:href CDATA #IMPLIED xlink:label CDATA #IMPLIED xlink:from CDATA #IMPLIED xlink:to CDATA #IMPLIED xlink:show (none) #FIXED "none" xlink:actuate (none) #FIXED "none" content-type CDATA #IMPLIED >
The definition above has been edited for clarity. RDDL has been defined using Modularization for XHTML. Following this recommendation, element prefixing can be overridden using internal subset parsed entities.
xlink:arcrole defines the type of the link. Software perfoming resource resolution may dispatch
resource is intended to refer to a schema, the arcrole may be used to determine the type of the schema.
e.g. A DTD, XSD, or RDF Schema. In this case such schemata
are named by a URI. The URI should be well known. For example:
XHTMLmay be referenced by
XSDmay be referenced by
RDF Schemamay be referenced by
The document http://www.openhealth.org/RDDL/arcrole.htm is itself a RDDL directory.
xlink:role defaults to the RDDL namespace URI:
In general it will not be otherwise specified but may be used to distinguish among related
schemata such as for HTML strict, transitional and frameset. The
xlink:role of a link should be thought of as the
type of the resource referenced by the link.
Ed. need to further discuss uses of and compare xmlink:arcrole and xlink:role
xlink:href known as the Locator attribute contains a mandatory URI referencing the target resource
A human readable short descriptive title. This should be specified but not in lieu of descriptive content.
Not used. The only legal value is "none".
Not used. The only legal value is "none".
An optional attribute defining the media content type
content-type attribute is not namespace qualified regardless of whether the containing
resource element is namespace prefixed or not.
In another example resources can be placed within the body, allowing intermingling of text descriptions and resource links.
<html> <head></head> <body> <rddl:resource xlink:type="simple" xlink:title="XML Schema" xlink:arcrole="http://www.openhealth.org/RDDL/arcroles.htm#XSD" xlink:href="http://www.openhealth.org/XMLCatalog/xcat-xhtml1.xsd" > <p>Here is the description of the XSD Schema being described within a <a class="element" href="#resource">resource</a> tag.</p> </rddl:resource> </body> </html>
Here is the description of the XSD Schema being described within a resource tag.
Below are the resources defined within this document
A CSS stylesheet used to provide the "look-and-feel" of this document.
The RDDL DTD is defined using Modularization for XHTML