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Re: SPARQL grammar... in BNF? N3?

From: Yosi Scharf <syosi@MIT.EDU>
Date: Wed, 08 Feb 2006 12:35:47 -0500
Message-ID: <43EA2BF3.8010607@mit.edu>
To: Dan Connolly <connolly@w3.org>
CC: "Eric Prud'hommeaux" <eric@w3.org>, Tim Berners-Lee <timbl@w3.org>, public-cwm-talk@w3.org, Robert Crowell <crowell@MIT.EDU>

Dan Connolly wrote:

>Yosi, Tim, Eric,
>
>The SPARQL parser in cwm... it seems to be built from EricP's
>BNF...
>
>
>|    if web:
>|        File = urllib.urlopen('http://www.w3.org/2005/01/yacker/uploads/sparqlTest/bnf')
> -- http://www.w3.org/2000/10/swap/sparql/sparql-grammar.py
>
>  
>
Wow. That line, and indeed that entire file, appears to be an incredible
red herring. sparql-grammar.py is not used anywhere, and never worked.
It was an early attempt of mine, before I switched to yacker.

I used yacker on a file I had modified to be LL(0). I think this was
http://www.w3.org/2005/01/yacker/uploads/yosiJune28a/bnf . Running that
through yacker (almost) got me
http://www.w3.org/2000/10/swap/grammar/sparql . I manually rewrote some
of the worst regexps in it for speed, however, the last of those
modifications being on July 28. Therefore, any changes to the SPARQL
grammar after that time have not been tracked. Cwm's sparql support uses
this. The was this works is shown in
http://www.w3.org/2000/10/swap/sparql/Makefile


Yosi

>In the DAWG, the editors added a .jj version of the grammar
>and are considering what other formats to publish.
>  http://www.w3.org/2001/sw/DataAccess/rq23/parsers/sparql.jj
>  <- http://www.w3.org/2001/sw/DataAccess/rq23/parsers/
>  <- http://www.w3.org/2001/sw/DataAccess/rq23/#sparqlGrammar
>
>Is BNF the one we want/need?
>
>EricP, have you generated a turtle/n3 version of the SPARQL grammar?
>
>Yosi, what's the status of N3 parsers based on n3.n3? Do they
>work yet? What about using that approach for the SPARQL parser?
>
>  
>
Received on Wednesday, 8 February 2006 17:36:29 GMT

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