- From: Tim Berners-Lee <timbl@w3.org>
- Date: Fri, 19 Aug 2005 07:12:44 -0400
- To: Richard Newman <r.newman@reading.ac.uk>
- Cc: public-rdf-dawg-comments@w3.org, Yosi Scharf <syosi@mit.edu>
Richard, I didn't realize the grammar in the spec is machine-generated. Maybe it should be hand-edited and everything else generated from it. Yosi (on vacation right now) has generated (with a small hand tweak) the CFG grammar in RDF from the spec. (See sparql* in http://www.w3.org/2000/10/swap/grammar/ ) This is in plain BNF ( cfg:mustBeOneSequence properties with nested RDF collections ) See the bnf.n3 ontology in that directory as well as the bnf-rules.n3 which go from some forms of ebnf to bnf, also in that directory. Tim On Aug 18, 2005, at 16:26, Richard Newman wrote: > As I recall from discussions with Andy Seaborne while I was > implementing twinql[1], the grammar in the SPARQL docs are directly > generated from a JavaCC grammar file. The source, therefore, is > machine-consumable -- at least, if you're using JavaCC! > > However, the output is not a particular friendly grammar to work > with -- optional dots after productions, for example, tripped up my > tool (so twinql makes them compulsory), and it took a bit of work > to get it into a usable state (as I detailed in a previous email[2]). > > -R > > [1] <http://www.holygoat.co.uk/projects/twinql/> > [2] <http://lists.w3.org/Archives/Public/public-rdf-dawg-comments/ > 2005Aug/0055.html> > On 18 Aug 2005, at 11:28, Tim Berners-Lee wrote: > > >> >> This is a followup from a discussion between Yosi Scharf, >> implementer of SPARQL in cwm, currently on vacation, and Eric >> P'dH, co-editor of the spec, several weeks ago. >> >> Yosi has built his implementation of SPARQL from a file which is >> almost the one generated from the TR, but with a slight tweak to >> make the file grammar able to be parsed by a predictive parser [1] >> a simple form of LL(1) recursive descent parser. I understood >> that the tweak was editorial in that the it didn't change the >> language, just the way it was expressed as a context-free grammar. >> >> A situation in which code can be generated directly from the spec >> is a very strong position to be in. I am not aware of any time >> this has previously happened for a W3C language, but I may be >> wrong. As it is demonstrably simple to make the step here I would >> request it be done at last call stage before the call for >> implementation at CR. >> >> [1] http://www.inf.ed.ac.uk/teaching/courses/cs2/LectureNotes/ >> CS2Ah/LangProc/lp10.pdf >> >> Tim Berners-Lee >> MIT/CSAIL/DIG >> >> >> >
Received on Friday, 19 August 2005 11:12:58 UTC