Question on ANY (its use in RDF)
Marcus Carr
mrc at allette.com.au
Sun Jan 24 23:46:04 GMT 1999
Roger L. Costello wrote:
> I have a question about the ANY type. It is my understanding
> that an element defined to be of type ANY can contain any
> element that is defined *within* the DTD (i.e., it cannot use
> elements that are not defined in the DTD). Correct?
My advice to anyone is never accept a DTD that uses ANY. The only legimate use I
have ever seen for it is in an interim DTD during data conversion. It's a sloppy
use of a sloppy mechanism - for example, would you really want to support an
infinite number of nested rdf:Description elements? There is no preventing this -
even the DOCTYPE element can be nested within itself.
> How can rdf:Description contain the element cat:tables? It is
> not defined in rdf.dtd. I thought that ANY says that the element
> can contain any elements defined *within* the DTD?
> Here is RDF.dtd:
>
> ...
>
> <!ENTITY % value "( %rdfObj; | PCDATA )">
>
> <!ELEMENT rdf:li ( %value; )>
>
Nor is the element PCDATA, used in the parameter entity named value. If this is
supposed to be #PCDATA, it needs to appear before %rdfObj;. Unless we're missing
something about extending this DTD, it appears to be a dud. Someone has not been
very considerate of your time.
--
Regards,
Marcus Carr email: mrc at allette.com.au
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Allette Systems (Australia) www: http://www.allette.com.au
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