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Re: Collection / Grammar Issue

From: Eric Prud'hommeaux <eric@w3.org>
Date: Sat, 2 Nov 2013 19:57:15 -0400
To: Alex Milowski <alex@milowski.com>
Cc: public-rdf-comments@w3.org
Message-ID: <20131102235714.GB4877@w3.org>
* Alex Milowski <alex@milowski.com> [2013-05-15 16:41-0700]
> 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 ) ) .
> 
> 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

There was a discussion around this, but there were look-ahead
problems.
<http://lists.w3.org/Archives/Public/public-rdf-comments/2013May/thread#msg43>
In the end, we just modified the example to have a predicate and
object following the outer collection:
[[
Example 24

@prefix : <http://example.org/stuff/1.0/> .
(1 [:p :q] ( 2 ) ) :p2 :q2 .
]]

If this addresses your comment, please reply with the subject prefixed
by "[RESOLVED]".


> BTW, it would be a wonderful editorial change to number the examples.

Done -- tx.


> [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

-- 
-ericP

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Received on Saturday, 2 November 2013 23:57:46 UTC

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