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Re: [DTB] Action 681 completed

From: Axel Polleres <axel.polleres@deri.org>
Date: Tue, 03 Feb 2009 09:06:17 +0000
Message-ID: <49880909.2090008@deri.org>
To: Jos de Bruijn <debruijn@inf.unibz.it>
CC: "Public-Rif-Wg (E-mail)" <public-rif-wg@w3.org>

Jos de Bruijn wrote:
> Axel Polleres wrote:
>> p.s.: I also removed the now obsolete predicate hasDatatype, which was
>> the "predecessor" of
>>   isLiteralOfType
>> and
>>   isLiteralNotOfType
>> and added the respective examples and Editor's notes now under
>> isLiteralOfType.
>> Two more questions open:
>> 1)  I thought whether we also need:
>>    IsLiteral, IsNotLiteral
>>  While the former can be  easily emulated by: idLiteralOfType (l ?X ),
>> just leaving the variable free, especially the latter might be useful?
>> Opinions?
> IsNotLiteral(?x) or isLiteralNotOfType(?x, int)
> is equivalent to
> isNotInteger(?x)
> And so, we would bring disjunction back into the language if we were to
> include IsNotLiteral.

makes sense... let's leave it out then, iiiih.


>> 2) Naming convention... I know we had agreed on isLiteralOfType and
>> isLiteralNotOfType in the teleconf., but now, in the light of drafting
>> literal-equal and literal-not-equal
>> I ask myself which naming convention to stick to:
>>  CamelCase or dash-separated ?
>> best,
>> Axel
>> Jos de Bruijn wrote:
>>> <snip/>
>>>>>> Note (also an editor's note in the document):
>>>>>>  I assumed the second argument of isLiteralOfType to be a rif:iri
>>>>>> at the
>>>>>> moment. As we defined a datatype identifier just as a unicode string
>>>>>> representing an IRI in the definition of symbol spaces, it might be
>>>>>> better to restrict the domain of the second argument to strings, yes?
>>>>> I disagree. A rif:iri constant can denote an actual datatype, so you
>>>>> can
>>>>> speak about actual datatypes when speaking about the types of literals.
>>>> This is what we say so far:
>>>> http://www.w3.org/2005/rules/wiki/DTB#Symbol_Spaces
>>>> "The identifier of a symbol space is a sequence of Unicode characters
>>>> that form an absolute IRI."
>>>> It is not an IRI constant, although the current definitions of
>>>> isLiteralOfType  and isLiteralNotOfType talk about IRI constants as the
>>>> second argument.
>>> that's fine.
>>>> I am happy with either keeping it like that or changing it, just wanted
>>>> to point out that there are two options.
>>>>> In fact, it would have been best if in BLD semantic structures the IRIs
>>>>> of datatypes are mapped to the corresponding datatypes, e.g.,
>>>>> xsd:string
>>>>> is mapped to the XML schema string datatype.  One could then, in DTB,
>>>>> speak only about values and datatypes, which will be much more
>>>>> convenient and much more elegant.
>>>> I am not sure what you want to say here, can you explain/maybe
>>>> illustrate with an example?
>>> I propose to extend the definition of semantic structure [1] by adding
>>> the following conditions to point 1 of the definition:
>>> - If a constant c \in Const is an IRI constant "d"^^rif:iri and d is a
>>> datatype identifier, i.e., d \in DTS, then I_C(d) is the datatype [2]
>>> identified by d.
>>> Thinking again about this, we might get away with this change without
>>> redoing last call.  The only real implication it has is that equality
>>> statements of the form
>>> xsd:integer=xsd:string
>>> are currently not inconsistent, but with the proposed change they do
>>> become inconsistent.
>>> But we anyway don't want people to write this kind of statement; in
>>> fact, people should not use datatype identifiers outside of constants
>>> and isLiteralOfType/isLiteralNotOfType statements.
>>> Best, Jos
>>> [1] http://www.w3.org/2005/rules/wiki/BLD#Semantic_Structures
>>>> Thanks,
>>>> Axel
>>>>> We should not have moved BLD to last call before finalizing DTB :-(
>>>>> I now think we should probably redo BLD last call, after finalizing
>>>>> DTB.
>>>>>> Moreover, I think by dropping the specific guard predicates, we can
>>>>>> get
>>>>>> rid of the definition of short names for symbol spaces as well.
>>>>> Yes.
>>>>> Best, Jos
>>>>>> Axel

Dr. Axel Polleres
Digital Enterprise Research Institute, National University of Ireland, 
email: axel.polleres@deri.org  url: http://www.polleres.net/
Received on Tuesday, 3 February 2009 09:07:04 UTC

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