[Xapian-devel] GSOC 2011 - QueryParser Reimplementation

[Dan Colish]

On Monday, March 21, 2011 at 2:37 AM, Maheshwar wrote:
> hello everyone,
> I am Maheshwar, a prefinal year Computer Science undergraduate student at BITS-Pilani, India. When i was going through the GSOC ideas , i felt interested in Quesry parser project. Till now i have implemented a couple of LL(1) parsers as a part of my assignment in Compiler construction course, so i would love to join and contribute to this project. So can any one tell me how to go about the project as i am new to xapian.
> 
> 
> -- 
> Regards,
> Maheshwar
> 3rd Year B.E Computer Science
> BITS-Pilani, Rajasthan
> 
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Hello Maheshwar! 

For getting started, the simplest thing to do is get a development environment setup and start reading the xapian code. If you have not looked at the tickets in trac for the queryparser yet, I would look at those as well.

The query parser is implemented using Lemon and the main body of code for it is under xapian-core/queryparser/queryparser.lemony. If you've used yacc or cup or any other LALR tool you'll recognize this code immediately. I would also study the language requirements linked to from our GSoC page. We will be using that working definition to refactor the existing grammar and begin writing our new parser. I have already begun to work on this refactoring; you can see my grammar here http://trac.xapian.org/attachment/ticket/521/grammar.out. This is not yet complete, but it is a BNF style grammar showing the direction I'd like to go in.

Let us know when you get set up and you've had a chance to read the existing parser implementation; then we can talk more about what a new parser would require and how to go about building it. 

-- Dan