RE: Chemistry and the Semantic Web

Eric:

URN syntax does not support fragments. This from RFC 2141 - URN Syntax:

   2.3.2 The other reserved characters

   RFC 1630 [2] reserves the characters "/", "?", and "#" for particular
   purposes. The URN-WG has not yet debated the applicability and
   precise semantics of those purposes as applied to URNs. Therefore,
   these characters are RESERVED for future developments.  Namespace
   developers SHOULD NOT use these characters in unencoded form, but
   rather use the appropriate %-encoding for each character.

I'm, not sure though what you intend by %-encoding the '#' char. XPointer is
a _client-side_ addressing mechanism, i.e. it works by using URI fragments,
which are incompatible with URN syntax.

Regards,

Tony


Tony Hammond

New Technology, Nature Publishing Group
4 Crinan Street, London N1 9XW, UK 

tel:+44-20-7843-4659
mailto:t.hammond@nature.com



> -----Original Message-----
> From: Eric Jain [mailto:Eric.Jain@isb-sib.ch] 
> Sent: 01 July 2004 09:04
> To: Eric.Neumann@aventis.com
> Cc: public-semweb-lifesci@w3.org
> Subject: Re: Chemistry and the Semantic Web
> 
> 
> 
> Eric.Neumann@aventis.com wrote:
> > From my understanding of XPaths 
> > (http://www.w3.org/TR/xpath#section-Introduction),
> > they can be used "within" URIs. So mapping an RDF statement to a 
> > specific Chem-XML node or group should be doable. Am I mis-informed,
> > or is this part of the standard W3C model? Of course, I'm 
> not sure how
> > this would look appended to a LSID URN:
> > "urn:lsid:www.cas.org:CA:33069-62-4#feature=21" ???
> 
> You are right, XPaths can indeed be used in URLs.
> 
> Then again... According to the LSID specification, the object part of 
> the identifier must be an "alphanumeric sequence". But, 
> looking at the 
> examples, they seem to have a rather broad definition of 
> "alphanumeric".
> 
> I am not familiar with CML, but imagine you could do 
> something like this:
> 
>    urn:lsid:cas.org:ca:33069-62-4.xml#xpointer(//feature[@id='21'])
> 
> If there is a limited number of element types that need to be 
> linked to, 
> another option may be:
> 
>    urn:lsid:cas.org:ca.feature:33069-62-4#21
> 
> Note that some RDF tools (e.g. Protege) assume that your URIs can be 
> split into a namespace part and an XML NCName. Also, the '#' 
> character 
> will need to be encoded when used as part of the URL in an HTTP GET 
> request...
> 



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Received on Thursday, 1 July 2004 04:45:23 UTC