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Re: Collection / Grammar Issue

From: Gavin Carothers <gavin@carothers.name>
Date: Wed, 15 May 2013 19:44:43 -0700
Message-ID: <CAPqY83xKqgs+bDTZ=PGkzHatL7A5sbnjH2jMvhLLt+pndCvzMQ@mail.gmail.com>
To: Sandro Hawke <sandro@w3.org>, "Eric Prud'hommeaux" <eric@w3.org>
Cc: Alex Milowski <alex@milowski.com>, "public-rdf-comments@w3.org" <public-rdf-comments@w3.org>
I have no idea. We're the ones who wrote the example Sandro ;) ... eric?

RDF collections can be nested and can involve other syntactic forms:

@prefix : <http://example.org/stuff/1.0/> .
(1 [:p :q] ( 2 ) ) .

is syntactic sugar for:

@prefix rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#> .
    _:b0  rdf:first  1 ;
          rdf:rest   _:b1 .
    _:b1  rdf:first  _:b2 .
    _:b2  :p         :q .
    _:b1  rdf:rest   _:b3 .
    _:b3  rdf:first  _:b4 .
    _:b4  rdf:first  2 ;
          rdf:rest   rdf:nil .
    _:b3  rdf:rest   rdf:nil .




On Wed, May 15, 2013 at 7:34 PM, Sandro Hawke <sandro@w3.org> wrote:

>  On 05/15/2013 07:41 PM, Alex Milowski wrote:
>
>  I ran across a problem while implementing a Turtle parser.
>
>  In section 3 of [1], the 7th example is:
>
>  @prefix : <http://example.org/stuff/1.0/> .
> (1 [:p :q] ( 2 ) ) .
>
>
> (unofficial reply, trying to clarify)
>
> Why would you want a turtle file that's just a list?   How would you use
> that?
>
>         -- Sandro
>
>
>   The production for triples in section 6.5 is:
>
>  [6] triples ::= subject predicateObjectList | blankNodePropertyList
> predicateObjectList?
>  [7] predicateObjectList ::= verb objectList (';' (verb objectList)?)*
>  [10] subject ::= iri | BlankNode | collection
>
>  According to these productions, the example is invalid.  The subject
> reduces to the collection and must be followed by a verb.  Yet, the example
> does not have a following predicate object list.
>
>  If this is truly suppose to be valid, I think the productions need to be:
>
>     triples ::= subject predicateObjectList |
>                         collection predicateObjectList? |
>                         blankNodePropertyList predicateObjectList?
>    subject ::= iri | BlankNode
>
>  BTW, it would be a wonderful editorial change to number the examples.
>
>  [1] http://www.w3.org/TR/2013/CR-turtle-20130219/
>
>  --
> --Alex Milowski
> "The excellence of grammar as a guide is proportional to the paucity of the
> inflexions, i.e. to the degree of analysis effected by the language
> considered."
>
> Bertrand Russell in a footnote of Principles of Mathematics
>
>
>
Received on Thursday, 16 May 2013 02:45:15 UTC

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