- From: Graham Klyne <gk@ninebynine.org>
- Date: Sun, 21 Dec 2003 19:13:53 +0000
- To: "Jos De_Roo" <jos.deroo@agfa.com>
- Cc: www-rdf-interest@w3.org
At 13:34 21/12/03 +0100, Jos De_Roo wrote: > > BTW, in N3, what do you think this means?: > > > > :id :- { :a :b :c . > > :a1 :b1 :c1 . > > :a2 :b2 :c2 . } > > > > :id :- { :a3 :b3 :c3 . } > > > > (all in a single document.) > >I really don't know and have seen that ":-" only once >before (in one of your mails) but can't find it in >http://www.w3.org/DesignIssues/Notation3 >nor in >http://www.w3.org/2000/10/swap/grammar/n3-report Oh, I can't see it there either, but I'm sure it *was* there. Notation3 seems to be something of a moving target ;-) The form :- does appear, for example, in: http://dev.w3.org/cvsweb/2001/blindfold/sample/n3.bnf?rev=1.4&content-type=text/x-cvsweb-markup as: [[ property_list ::= void # to allow [...]. | verb space+ object_list | verb space+ object_list space+ ";" space+ property_list | ":-" anonnode #to allow two anonymous forms to be given eg [ a :Truth; :- { :sky :color :blue } ] ) | ":-" anonnode ";" property_list ; ]] (which is linked from http://www.w3.org/DesignIssues/Notation3) as: "n3.bnf from the blindfold tools") This happens to be a feature I use quite a lot, in the form: name :- node-expression where I have understood it to mean that the name (or expression) to the left of :- is a referent for the think on the right. Or, in the example above: [ a :Truth; :- { :sky :color :blue } ] I think would mean the same as: { :sky :color :blue } a :Truth I must confess that I have never seen this spelled out in detail, but I have had discussions with some people that tend to confirm this view. I use it particularly in this form: ex:someName :- (item1 item2 item3) to indicate that the first "cons" in the list is identified as ex:someName. > >> I've never felt the need for more than {triples} names; > >> those names are written on documents which have URI's > >> and those URI's are the pivotal points. > > > > Er, I'm not following you here > >We *call* some-set-of-triples in 2 different ways >1/ either as > { some-set-of-triples-in-notation3 } >2/ or as > <uri-of-some-set-of-triples>.log:semantics [I assume that is <uri-of-some-set-of-triples>!log:semantics per the current (2003-12-21) version of http://www.w3.org/DesignIssues/Notation3] Ah, I think I see. The difference here would seem to be in the use of log:semantics. My take on what we *call* some set-of-triples would be: 1/ either as { some-set-of-triples-in-notation3 } 2/ or as <uri-of-some-set-of-triples> I.e. that the URI and the {...} expression are interchangeable. To my mind, this: { some-set-of-triples-in-notation3 }!log:semantics would be equally valid. Indeed: :someName :- [{ some-set-of-triples-in-notation3 }!log:semantics] would be the same statement as: :someName log:semantics { some-set-of-triples-in-notation3 } by my understanding of :- and ! >All that is written in particular documents >which are URI identified and so we can >explicitly and precisely load that in engines. >There is a means to show what was loaded >and thus trusted. Yes... I think that name :- { ... } allows one to do the same thing within a single Notation3 "document". #g ------------ Graham Klyne For email: http://www.ninebynine.org/#Contact
Received on Sunday, 21 December 2003 14:23:28 UTC