xml-dev - Re: XSchema Spec, Sections 2.0 and 2.1 (Draft 1)

[Chris Maden <crism@oreilly.com>]

[Simon St.Laurent]
> <!ELEMENT XSC:XSchema (Doc?, (ElementDecl | Entity | Notation |
> Namespace | XSchema)*)>

(1) Remember that namespaces confer no magic for validation; this
declaration probably meant to be:

<!ELEMENT XSC:XSchema (XSC:Doc?, (XSC:ElementDecl | XSC:Entity |
XSC:Notation | XSC:Namespace | XSC:XSchema)*)>

Me, I'm partial to lower-case, and would even prefer:

<!ELEMENT xsc:xschema (xsc:doc?, (xsc:elementdecl | xsc:entity |
xsc:notation | xsc:namespace | xsc:xschema)*)>

(2) I feel very strongly that XSchema should not define entities for
use in documents.  If it does, you're only inventing a new syntax for
DTDs, and inheriting all of their problems, to which I say: "big
deal".

The biggest problem with DTDs (IMO) is that they conflate definitions
for a class of documents with definitions for a single document
instance.  A schema should try, as cleanly as possible, to refer only
to the *class* of documents, and leave entities out of it.  After
XSchema is successful, then we can move on to tackle a new and better
syntax for entity declaration.

Now, it may be that the "Entity" element is only intended for use
within the schema.  If so, great, but I think the name should reflect
that.  Maybe call it "module"?

<xsc:module id="para.content">
  <xsc:mixed>
    <xsc:element idref="emph"/>
    <xsc:element idref="term"/>
    <xsc:element idref="quote"/>
    <xsc:element idref="literal"/>
  </xsc:mixed>
</xsc:module>

<xsc:elementdecl id="para">
  <xsc:content>
    <xsc:modref idref="para.content"/>
  </xsc:content>
</xsc:elementdecl>

(Note: I'm making up the content model syntax here.  But you get the
idea.)

-Chris
-- 
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