On 29/11/15 11:33, james anderson wrote:
good morning;
On 2015-11-29, at 11:33, Andy Seaborne <a...@apache.org> wrote:
[…]
Is there any theoretical or technical obstacle to this?
There's no obstacle. A Google Summer of Code project added this to Apache Jena
this year and it'll be in the next release.
It follows the design you gave:
https://jena.apache.org/documentation/query/construct-quad.html
while a quite reasonable extension proposal and one which leads one to wonder
why it was left out of the 1.1 recommendation, there are questions.
Many reasons:
No standardized syntax and MIME type.
SPARQL 1.1 predates standardized Trig and N-quads - indeed,
"RDF Dataset" was not in RDF - it was only in SPARQL.
Limited resources. Limited time. Limited interest.
http://www.w3.org/TR/sparql-features/
- what identifier does arq intend to us in the service description to indicate
its support
- as a matter of interoperability, is the elided graph case in the “complete
form” example really in instance of the grammar which appears later in the
document? given the example, this reader would have expected a production of
the form
( 'GRAPH’ )? VarOrIri '{' TriplesTemplate? ‘}’
i.e. "TriG-with-variables", rather than SPARQL Update quad blocks.
- which end does the elision serve?
Thank you to Google for funding the work of Qihong Lin.
Getting the project finished in time matters. GSoC projects are fixed
length.
It is also desirable for it to be a simple extension for everyone but it
is not incremental to add and remain LL(1) AKA easy parsing (it's 3
separate additional local LL(2) changes I think); obviously it is
possible to do convert LL(2) to LL(1) but it needs rewriting all the
template rules, making it not a just local change in one rule.
Not everyone is using the same parser generator (ARQ uses javacc so lots
of bells and whistles here like variable local lookahead). The GRAPH
implementation is a local change in one part of the grammar.
When in standards mode (default), the grammar remains what is in the
spec, not something supposedly equivalent.
Andy
best regards, from berlin,
---
james anderson | ja...@dydra.com | http://dydra.com
