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Re: Quetions about cwm/N3

From: Sean B. Palmer <sean@mysterylights.com>
Date: Tue, 7 May 2002 15:35:46 +0100
Message-ID: <003b01c1f5d4$7d2f2c80$04bd0150@localhost>
To: "Graham Klyne" <GK@NineByNine.org>
Cc: "RDF interest group" <www-rdf-interest@w3.org>
Hi Graham,

> (1) what is the keyword 'this' meant to mean?  I think I
> read somewhere that it's the enclosing formula.  In the
> absence of {...} constructs, that could be replaced by a
> URIref '<#>', I think.

It does identify the encosing formula (TimBL explained it as something like
"<> log:semantics this ."), but you can't use the URI-ref <#> for that,
since the fragment identifer syntax of XML RDF does not currently specify
that the empty fragment identifies the enclosing formula (it could be made
to do so, I suppose). Note that CWM uses <#_formula> to identify the root
formula: a nasty hack. FWIW, my latest API treats it as a completely blank
node (labelling it with Python's "None").

> Is there a convention for applying URIs to formulae?  (My software
> treats them as blank nodes, but the ':-' operator can be used to assign
> the formula to a labelled node.)

Yes, I think :- is the only way to do it.

> (2) is the character '-' intended to be allowed in QNames?  I
> thought not, but I've come across some cwm output that contains
> this character.

Try: http://infomesh.net/2002/n3qname.html TimBL reserved it in the
DesignIssues document, but many implementations still support it (note the
great "-" to "_" mapping solution in the N3 DesignIssues document).

Kindest Regards,
Sean B. Palmer
@prefix : <http://purl.org/net/swn#> .
:Sean :homepage <http://purl.org/net/sbp/> .
Received on Tuesday, 7 May 2002 10:35:54 UTC

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