We're using Antlr for our query parsing. What I like about it: - flexibility of separate lexer/parser and tree api - excellent IDE for building/testing the grammar However, the learning curve was quite long for me, although this was my first real encounter with parsers.
Peter On Fri, Sep 25, 2009 at 9:58 AM, Grant Ingersoll <gsing...@apache.org>wrote: > Has anyone looked/used Antlr for Query Parser capabilities? There was some > discussion over at Apache Labs that might bear discussing in light of our > new Query Parser contrib. > > Begin forwarded message: > > *From: *Tim Williams <william...@gmail.com> > *Date: *August 17, 2009 8:09:04 PM EDT > *To: *l...@labs.apache.org > *Subject: **Re: Lab - Esqueranto* > *Reply-To: *l...@labs.apache.org > > On Mon, Aug 17, 2009 at 7:00 PM, Grant Ingersoll<gsing...@apache.org> > 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.... > > Thanks, > --tim > > --------------------------------------------------------------------- > To unsubscribe, e-mail: labs-unsubscr...@labs.apache.org > For additional commands, e-mail: labs-h...@labs.apache.org > > > >
