XSchema Spec - Element Declarations (Section 2.2), Draft 4

Simon St.Laurent (SimonStL@classic.msn.com)
Thu, 9 Jul 98 20:19:04 UT

Following is the latest draft of Section 2.2 on Element declarations.
XSC:More has been corrected to be optional, and a bit more explanation of some
components has been added to address questions sent me privately. I would
have changed the names, but the vote was for the status quo.

As always, a prettier HTML version of this will be posted shortly at
http://purl.oclc.org/NET/xschema.

Simon St.Laurent
Dynamic HTML: A Primer / XML: A Primer / Cookies

2.2 Element Declarations

Element declarations in XSchemas are made using the XSC:ElementDecl element
and its contents:

<!ELEMENT XSC:ElementDecl (XSC:Doc?, XSC:More?, (XSC:Ref | XSC:Choice |
XSC:Seq | XSC:Empty | XSC:Any | XSC:PCData | XSC:Mixed), XSC:AttDef*)>
<!-- name is the element name -->
<!ATTLIST XSC:ElementDecl
name NMTOKEN #REQUIRED
id ID #IMPLIED
root (Recommended | Possible | Unlikely) "Possible">

The XSC:name attribute identifies the name of the element, and is required. An
element declaration would look like:

<XSC:ElementDecl name="Species">
...additionalElementInformation...
</XSC:ElementDecl>

This declaration would declare an element named "Species", which would appear
in an instance as:

<Species>...content...</Species>

The XSC:name attribute must be unique within the set of elements, as it
provides the name of the element as declared here, and is also used by other
elements to refer to this element in their content model declarations.

The XSC:id attribute, if it appears, must be unique within the document. This
attribute may be used to uniquely identify this XSC:ElementDecl element for
reference using XPointers and other tools.

The XSC:root attribute provides authoring tools with a guide for which
elements are likely root elements for documents. This is intended to simplify
the choices presented to authors during document composition. Composition
tools could use this to build a menu of likely starting points for a document.

Note that an element must declare a content model of some type, even if that
content model is empty. Documentation (in the XSC:Doc element), non-XSchema
extensions (in the XSC:More element) and attribute declarations (using
XSC:AttDef elements) are optional.

Documentation about the element, additional extensions, content-model
information, and attribute information are stored as sub-elements of the
XSC:ElementDecl element. Documentation is covered in 2.6.1, Documentation
Extensions. Additional extensions are covered in 2.6.2, Further Extensions.
Content Model is covered in 2.3, Content Model Declarations, and attributes
are covered in 2.4, Attribute Declarations.