- From: Pat Hayes <phayes@ihmc.us>
- Date: Thu, 8 Sep 2011 17:51:48 -0700
- To: Richard Cyganiak <richard@cyganiak.de>
- Cc: RDF Working Group WG <public-rdf-wg@w3.org>, Ivan Herman <ivan@w3.org>
On Sep 8, 2011, at 9:43 AM, Richard Cyganiak wrote: > Pat, > > On 8 Sep 2011, at 18:04, Pat Hayes wrote: >>> [[ >>> 2c. The abstract syntax has a lexical form and language tag (like in RDF 2004). The value is assigned directly (like in RDF 2004), bypassing the datatype. The datatype has an empty lexical space and empty L2V mapping. >>> ]] >>> >>> This is *not* more elaborate than 2a or 2b and this *does* meet the definition of datatype. >> >> OK, I am apparently completely confused by this. > > Well, let me explain. Thanks for trying :-) > >> If it has a lexical form, how can the lexical space be empty? > > The *literal* has a lexical form. > > The *datatype's* lexical space is empty. > > Consider "hello"^^xsd:integer. That's a typed literal and it has a lexical form "hello". That lexical form is not in the lexical space of the literal's datatype. So the literal is ill-typed. One cannot have a well-typed literal with a lexical form when the datatype has an empty lexical space. Yet there are, apparently, well-typed literals with this type, and (you tell me) they have a lexical form. Which ought to be impossible. > >> I would suggest that this is *extremely* hard to understand and make sense of. > > “lexical form” and “lexical space” are two separate concepts in RDF, and have always been. There's nothing new here. Of course they are different concpets. One is the set of all the others. But you want this set to be empty, but to also have members. Which does not make sense. > >> At least, it is for me. And as the semantics editor, I have to say that I could not write a coherent semantics for this, as it appears to be self-contradictory. > > There will be a few minor changes in Section 1.4, nothing else. I'll happily provide wording. I'd be delighted to include it, as long as I can make sense of it. Right now I would rate the chances of that being low. Pat > > Best, > Richard > > > >> >> Pat >> >>> >>> This makes the votes submitted so far kind of moot. >>> >>> Best, >>> Richard >>> >>> >>> >>>> >>>> 3. Lexical form is "foo", datatype is unique to the tag, ie there is one datatype per tag. These are conventional datatypes with a welldefined L2V mapping. Again there are several (well, two) options based on this idea. >>>> >>>> 3a. We invent an IRI naming convention for these datatypes, eg rdf:taggedLiteral/tag. Then this is the type of the literal. (Pain: inventing this open-ended naming convention.) >>>> 3b. These per-tag datatypes are all anonymous and have no IRI, but are sub-datatypes of rdf:TaggedLiteral, which is returned as the type for them all. (Pain: overly elaborate; potentially confusing; need to define a new notion of sub-datatype.) >>>> >>>> 4. Lexical form is "foo@tag", where tag is required to be nonempty and not contain '@' (just as in the rdf:PlainLIteral spec). This is a conventional datatype (it is rdf:PlainLiteral restricted to nonempty tags) with a conventional L2V mapping. (Pain: might be considered to be the wrong lexical form (??)) (Positive: conforms closely to existing specs; simple; extra tag information might be useful?) >>>> >>>> ------ >>>> >>>> On balance, my own vote is for either 2b or 4, and the longer I think about it, the better 4 looks after all. If we choose one of the 2 family, I would plead editorial discretion to be allowed to choose among them depending on which one fits best with the semantics, when we get down to details. They differ only in theoretical issues. Well, OK, I give up on 2a. >>>> >>>> Pat >>>> >>>> ------------------------------------------------------------ >>>> IHMC (850)434 8903 or (650)494 3973 >>>> 40 South Alcaniz St. (850)202 4416 office >>>> Pensacola (850)202 4440 fax >>>> FL 32502 (850)291 0667 mobile >>>> phayesAT-SIGNihmc.us http://www.ihmc.us/users/phayes >>>> >>>> >>>> >>>> >>>> >>>> >>> >>> >>> >> >> ------------------------------------------------------------ >> IHMC (850)434 8903 or (650)494 3973 >> 40 South Alcaniz St. (850)202 4416 office >> Pensacola (850)202 4440 fax >> FL 32502 (850)291 0667 mobile >> phayesAT-SIGNihmc.us http://www.ihmc.us/users/phayes >> >> >> >> >> >> > > > ------------------------------------------------------------ IHMC (850)434 8903 or (650)494 3973 40 South Alcaniz St. (850)202 4416 office Pensacola (850)202 4440 fax FL 32502 (850)291 0667 mobile phayesAT-SIGNihmc.us http://www.ihmc.us/users/phayes
Received on Friday, 9 September 2011 00:52:32 UTC