- From: Seaborne, Andy <andy.seaborne@hp.com>
- Date: Tue, 31 Aug 2004 11:51:57 +0100
- To: Alberto Reggiori <alberto@asemantics.com>
- Cc: public-rdf-dawg@w3.org
> yes it makes sense - but I then do not understand why we need to make > the syntax so much N3 like, using PREFIX and use :prefix notation > instead of current RDQL USING prefix FOR <URI> RDQL syntax can't handle the default prefix. Andy -------- Original Message -------- > From: Alberto Reggiori <> > Date: 30 August 2004 16:33 > > Andy, thanks for the clarifications - some short replies inline below... > > On Aug 27, 2004, at 4:47 PM, Seaborne, Andy wrote: > > > > There are a number of reasons behind the proposal: none of these is a > > single reason to go one way of another. > > > > 1/ We do need some kind of grouping because disjunction is a > > requirement. It also makes nested optionals possible but we haven't > > decided on those yet. The proposal isn't finished or fixed; at least > > it can capture the test cases we will need. > > I think it was already clear to me why we need grouping now (and I was > not arguing/talking whether or not we need it) I simply wonder what > would be the best syntactic choice from an average programmer/user > point of view. And I feel it is good to have this syntax discussion now > and avoid to postpone it - rather we start prototyping the future DAWG > language... > > > > > 2/ We may relax the WHERE/AND split, so expressions can appear where > > it is most natural for them to appear in the query pattern Something > > has to be done as constraints apply to a graph pattern group, not the > > whole query, when we have grouping. It has been pointed out that > > constraints and triples and no different aside from syntactic form. > > A WG decision which I await. > > sure it is clear > > > A form based on "( pattern ) AND constraints" would work if the WG > > decides to keep them separate. > > I would vote for this - which is also closer to current RDQL syntax - > or just replace AND with a better WITH or CONSTRAINTS keyword, to avoid > to confuse the users with the meaning of that "and" (due a > graph-pattern is a bunch of AND-ed triple-patterns) > > E.g. " ( pattern ) WITH constraints" > > > > > 3/ The usage of triples written in () is not found else where. It is > > yet another way to write graphs (with variables). Writing out all > > the triples can be a bit tedious and N3 (rather Turtle+vars) allows > > ";" and "," to be more concise. Makes no difference to query > > execution if the syntactic sugar is just flattened into triple > > patterns. > > > > This has the advantage that the query has at least a similar form to > > one of the data representations. (RDF/XML is not a natural option > > for templating here as far as I can see because of the need to write > > variables into the XML.) > > clear - but I find this N3/Lisp like syntax a bit far from simpler > original SquishQL/RDQLsyntax - which most users still like... > > that's also why I always liked the simplicity of rdfdb query language > > http://www.guha.com/rdfdb/query.html > > (see also simple insert syntax) > > > > > 4/ The WG has a duty to not make alignment with rules difficult for > > no good reason. Yet-another-pattern language is just a nuisance. > > Maybe we can get sufficiently close, at least in part of the query > > language, to help application writer, maybe we can't. That suggests > > not using [] for optionals BTW. > > humm rules...ok...I will not speak about this :) I would rather leave > it for discussion to others DAWG-ers... > > > > > 5/ "Simpler" is a value judgement - you aren't a lisp programmer are > > you :-)? The counter argument is that multiple use of the same > > symbol is confusing. > > yes your feeling is right - I never learned Lisp :o) > > > > > Re: USING: having USING at the end is at odds with RDF > > serializations where namespace prefixes are declared first. It also > > requires a two-pass paring process (second pass somewhere to fix up > > qnames into URIs). > > yes it makes sense - but I then do not understand why we need to make > the syntax so much N3 like, using PREFIX and use :prefix notation > instead of current RDQL USING prefix FOR <URI> > > anyway, yet another syntax discussion :) > > cheers > > Alberto
Received on Tuesday, 31 August 2004 10:53:13 UTC