- From: Andy Seaborne <andy.seaborne@epimorphics.com>
- Date: Fri, 21 Oct 2011 11:10:54 +0100
- To: public-rdf-wg@w3.org
On 20/10/11 14:39, Sandro Hawke wrote: > On Thu, 2011-10-20 at 14:58 +0200, Dan Brickley wrote: >> On 20 October 2011 14:47, Sandro Hawke<sandro@w3.org> wrote: >>> On Thu, 2011-10-20 at 13:21 +0200, Dan Brickley wrote: >>>> On 20 October 2011 13:13, Steve Harris<steve.harris@garlik.com> wrote: >>>>> I wouldn't be comfortable with marking Seq as "archaic" or similar unless there's a viable alternative, and I don't think List counts. >>>> >>>> Me neither. Nor "quaint", "twee", "retro" or "regrettable". It's just >>>> what it is, with no great mystery or confusion. >>> >>> Actually, there's a great deal of confusion. Please do explain -- in >>> one sentence for newbies -- why we have both Seq and List, and with Seq >>> better supported in RDF/XML and List better supported in Turtle, and how >>> someone should decide which to use. >> >> Sure - good idea. >> >> "The first RDF/XML specifications used a class rdf:Seq with numbered >> relationships to describe ordered lists; however when the later OWL WG >> were arm-twisted by W3C staff into using RDF as the syntax to define >> their language, they persuaded the RDF Core group (and others, e.g. >> N3/Turtle) to adopt a new list mechanism that used a linked list style >> that made it easier to tell when a list description was incomplete, at >> the cost of extra triples." > > Nice :-) but you didn't answer the second-half of the question. > > Also, why didn't you (the 2001-2004 RDF Core WG) just add an end-marker, > if that was the objective? I missed that particular debate. > >>> (To put it differently, I think it's quite harmful to the RDF to not deprecate Seq.) >> >> I guess you're not paying by the triple for storage? > > I should hope that no one stores well-formed lists as triples. Unfortunately, that isn't how it is. The reasons are: 1/ The store has to support the triples view anyway because those triples really are there (count). 2/ ... and so applications access Seqs/lists as triples (ugly though it may be) so the change isn't that helpful. 3/ Handling variable length data items is harder than fixed length ones (c.f. arrays in SQL:2008). 4/ There needs to be list-values variables in query to work with them. Andy > Can you think of any way we could merge Seq and List? Have well-formed > sequences and well-formed lists both mappable to native lists? That > would work fine, except for round-tripping.... > > -- Sandro > >> cheers, >> >> Dan >> > > >
Received on Friday, 21 October 2011 10:11:33 UTC