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Re: DTB status (on today's agenda)

From: Axel Polleres <axel.polleres@deri.org>
Date: Fri, 02 May 2008 15:08:43 +0100
Message-ID: <481B206B.3080500@deri.org>
To: Sandro Hawke <sandro@w3.org>
CC: debruijn@inf.unibz.it, "Public-Rif-Wg (E-mail)" <public-rif-wg@w3.org>

Sandro Hawke wrote:
>> Jos de Bruijn wrote:
>>>
>>> Sandro Hawke wrote:
>>>>> Let me reiterate (for the third time) my extremely simple compromise
>>>>> proposal.  Here expand(foo) means substitute with the prefix 
>>>>> definition of
>>>>> foo.
>>>>>
>>>>> 1. Standalone occurrence:
>>>>>     foo:bar ---> "expand(foo)bar"^^"http://www.w3.org/2007/rif#iri"
>>>>>
>>>>> 2. A ^^-occurrence:
>>>>>     "abc"^^foo:bar ----> "abc"^^"expand(foo)bar"
>>>> I can live with this, if we don't use "^^".   This was the second option
>>>> in my e-mail, although I accidentally expanded bar as well.
>>>>
>>>> The problem with ^^ is that it's very distinctive and is used in other
>>>> semantic web languages.  But in those languages, it's followed by a URI
>>>> constant not a string constant.    So I'd have to object that re-using
>>>> ^^ with this kind of type difference is too confusing to users.
>>> I thought that in RIF ^^ is also always followed by an IRI constant?
>> In those other languages you are speaking about, it is followed by a IRI 
>> in angle brackets or a CURIE:
>>
>> N3: http://www.w3.org/TeamSubmission/n3/
>>
>>     literal ::=	string dtlang
>>     dtlang ::=   "@"  langcode |	 "^^"  symbol
>>     symbol ::= explicituri | qname
>>     explicituri ::= <[^>]*>
>>     qname ::= /* what we called CURIE */
>>
>> Turtle: http://www.w3.org/TeamSubmission/turtle/
>>
>>     literal ::=  quotedString ( '@' language )? | datatypeString
>>                  | integer | double | decimal | boolean
>>     datatypeString ::= 	quotedString '^^' resource
>>     resource ::= uriref | qname
>>     uriref ::= '<' relativeURI '>'
>>     qname ::= /* what we called CURIE */
>>
>>
>> SPARQL: http://www.w3.org/TR/rdf-sparql-query/
>>
>>   RDFLiteral ::= String ( LANGTAG | ( '^^' IRIref ) )?
>>
>>   IRI_REF ::= '<' ([^<>"{}|^`\]-[#x00-#x20])* '>'
>>
>>   Note: No CURIEs allowed in the Grammar there for the type, although
>>       they use CURIEs in the examples in the spec... actually, that 
>> seems to be a bug in their grammar.
>>
>>
>>
>>
>>> I think we should stick with the ^^ in RIF, because its use actually 
>>> generalizes the use in the other semantic Web languages.
>> I fully agree that RIF presentation syntax should generalize those 
>> languages, yes. We already defer by putting the langtag in side the 
>> string, BTW.
> 
> Right, but Michael is adamantly against RIF-PS generalizing those
> languages. 

I am  adamantly against deviation from these languages, but I will 
accept a majority vote.

Axel

>  So, I can live with this other approach.   No pointy
> brackets and no ^^.
> 
>       -- Sandro
> 
>> Axel
>>
>>> Best, Jos
>>>
>>>> In my previous e-mail I wrote  a^^b as lit(a,b), which seems about
>>>> right.   I'm not sure what we should call "lit".   SWI-Prolog calls in
>>>> "type(b, a)". [1]
>>>> I suppose the obvious thing is "Const", so the change in the grammar is:
>>>>
>>>> Remove:
>>>>
>>>>    Const          ::= '"' UNICODESTRING '"^^' SYMSPACE
>>>>
>>>> Add (trying to keep current style):
>>>>
>>>>    Const          ::= 'Const(' '"' UNICODESTRING ',' '"' SYMSPACE '"' ')'
>>>>
>>>> Does that work?
>>>>
>>>> I'd also consider putting the symspace first (as in SWI-Prolog), because
>>>> in a sense it's the most-significant part.
>>>>
>>>>> If you do not like "..." for the after the ^^-part, use '...' or even 
>>>>> <...>.
>>>>> But, in the latter case, <...> CANNOT be used as a macro. That is,
>>>>>
>>>>>    <abc>  --X--> "abc"^^rif:iri.
>>>>>
>>>>> is a no-no.
>>>>>
>>>>> My proposal allows some simple form of context sensitivity, but not the
>>>>> above <...> macro atrocity (if <...> is also used after the ^^).
>>>>> I do not see why we need such a macro in the first place, if in most 
>>>>> cases
>>>>> we will be using foo:bar.
>>>> I can't think of any reason we need "<" ... ">", but we might.   I think
>>>> we can leave them out until/unless we need them.
>>>>
>>>>       -- Sandro
>>>>
>>>> [1] http://www.swi-prolog.org/packages/rdf2pl.html#sec:3.1
>>>>
>>
>> -- 
>> Dr. Axel Polleres, Digital Enterprise Research Institute (DERI)
>> email: axel.polleres@deri.org  url: http://www.polleres.net/
>>
>> rdfs:Resource owl:differentFrom xsd:anyURI .


-- 
Dr. Axel Polleres, Digital Enterprise Research Institute (DERI)
email: axel.polleres@deri.org  url: http://www.polleres.net/

rdfs:Resource owl:differentFrom xsd:anyURI .
Received on Friday, 2 May 2008 14:09:38 GMT

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