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From Tim Williams <>
Subject Re: Lab - Esqueranto
Date Tue, 18 Aug 2009 00:09:04 GMT
On Mon, Aug 17, 2009 at 7:00 PM, Grant Ingersoll<> wrote:
> On Aug 2, 2009, at 1:43 PM, Tim Williams wrote:
>> Hi Martin,
>> Sure, if it works like I envision it, Lucene would just be *one*
>> concrete tree grammar implementation - there could be others (ie
>> OracleText), I'm thinking it is broader than one implementation -
>> otherwise, I reckon it's Yet Another Lucene Query Parser (YALQP).
>> For more practical reasons, I'm not a Lucene committer and it'd be
>> slow going to play around with this through JIRA patches to their
>> sandbox.
> FWIW, Lucene has recently added a new, more flexible Query Parser that
> allows for separation of the various pieces (syntax, intermediate
> representation, Lucene Query).  You might want to check it out and see how
> that fits

Thanks Grant, yeah I've looked at that and it seems really (overly?)
complex for what I'm trying to achieve.  It seems to re-implement much
of the goodness that antlr provides for free.  For example, with antlr
I already get a lexer/parser grammar separate from the tree grammar.
So, to plug in a new parser syntax is trivial - just implement a new
lexer/parser grammar that provides tree rewrites consistent with a
lucene tree grammar.  Conversely, to implement a new concrete
implementation, just implement a new tree grammar for the existing
lexer/parser grammar.

Of course, maybe I'll get down this road and realize how naive my path
is and just switch over.  For now, just looking at a query parser
that, by itself, is approaching the size of the lucene core code base
is intimidating:)  Thanks for the pointer though, I'm subscribed over
there and keep an eye out for progress on the new parser....


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