From: Peter F. Patel-Schneider ([email protected])
Date: 01/09/01
From: pat hayes <[email protected]>
Subject: Re: (Part 2) Where did these syntax constraints come from?
Date: Tue, 9 Jan 2001 12:47:08 -0800
> >TBL> <restrictedBy>
> >TBL> <Restriction>
> >TBL> <hasValue>
> >TBL> I hoped that the english would improve. It is still really
> >TBL> non-evident from the markup what the restriction is. Also, it is a
> >TBL> wasteful use of markup. It is an example of excessive reification.
> >TBL> But I can't think of a better alternative.
> >
> >Yes, it's not pretty. If you have a better idea, say it NOW, or it will
> >be frozen.
>
> Well, how about just eliminating the <Restriction> brackets, which as
> far as I can see serve no useful purpose:
>
> <restrictedBy>
> <hasValue>
>
> and eliminating </Restriction> at the other end? We know this is a
> restriction since it follows <restrictedBy>, so why do we have to say
> so again?
We have to say it again so that RDF will know it. :-) As RDF does not
have a semantics, we cannot count on range information having any meaning
in RDF. :-( If we could count on range information, then we could use
<restrictedBy>
<rdf:Description>
<hasValue>
...
but this would not be much shorter> :-)
Actually, I think that the abbreviated syntax for RDF requires that a
property (like restrictedBy) contain a single resource. Look in section
2.2.2 of the RDF spec for a not-very-readable discussion of this aspect of
RDF.
peter
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