Re: Production rules for satisfying the "prefix_only_IRI" turtle parser test

Hi Greg and Richard,

Thanks both for clarifying this, I understand this now. Fixed.

https://github.com/robstewart57/rdf4h/commit/d07fd74a2465f2310c69386adfe58cd04d40dbec

--
Rob

On 19 November 2015 at 23:10, Richard Cyganiak <richard@cyganiak.de> wrote:

> Hi Rob,
>
> p: needs to satisfy either PNAME_LN or PNAME_NS:
>
> [136s]  PrefixedName    ::=     PNAME_LN | PNAME_NS
>
> Best,
> Richard
>
>
>
> > On 19 Nov 2015, at 17:59, Rob Stewart <robstewart57@gmail.com> wrote:
> >
> > There is a turtle parser test in the W3C unit tests labelled
> "prefix_only_IRI".
> >
> > The RDF to be parsed is:
> >
> > @prefix p: <http://a.example/s>.
> > p: <http://a.example/p> <http://a.example/o> .
> >
> > The RDF graph expected in memory is:
> >
> > <http://a.example/s> <http://a.example/p> <http://a.example/o> .
> >
> > Because p in p: has been expanded to http://a.example/s and what
> follows ":" is an empty string, so the expanded prefix for p is the URI for
> the subject.
> >
> > My question is about how this conforms to the turtle grammar rules at
> http://www.w3.org/TR/turtle/#sec-grammar-grammar . The relevant
> production rules are:
> >
> > [139s] PNAME_NS::= PN_PREFIX? ':'
> > [140s] PNAME_LN::= PNAME_NS PN_LOCAL
> > [168s] PN_LOCAL::= (PN_CHARS_U | ':' | [0-9] | PLX) ((PN_CHARS | '.' |
> ':' | PLX)* (PN_CHARS | ':' | PLX))?
> >
> > The "p:" satisfies PNAME_NS, so now to satisfy PN_LOCAL in order to
> satisfy PNAME_LN. In the "prefix_only_IRI" test case, what follows the ":"
> is an empty string. I don't see how an empty string can be satisfied by
> PN_LOCAL, given the first component of PN_LOCAL is:
> >
> > (PN_CHARS_U | ':' | [0-9] | PLX)
> >
> > So, how does the "prefix_only_IRI" turtle parsing test conform to the
> grammar rules for turtle syntax?
> >
> > Thanks,
> >
> > --
> > Rob Stewart
>
>