Anonymous content types (WAS: Re: XML trade off 1 - DTD vs XML Schema)

Rick Jelliffe ricko at
Wed Jul 21 20:36:28 BST 1999

From: John E. Simpson <simpson at>

>So (acknowledging that you mean it to apply only to XML schemas, and
>the following examples don't conform to legitimate XML DTD syntax)
>suggesting element content models such as:
>(The king element may contain any other single element)

Good examples.

> <!ELEMENT hands PAIR >
>(The hands element may contain any *pair* of other elements)
> <ELEMENT citizens UNIQUE >
>(The citizens element may contain any number of child elements, but
>child may appear only once within the citizens element)

Or maybe these could be split into SET and BAG in RDF fashion.

>Like that? These would all be subtypes of ANY, no?

If you like subtyping, sure. If you like extensibility, then I suppose
are extensions of EMPTY.

Rick Jelliffe

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