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From Christoph Kiehl <christ...@sulu3000.de>
Subject Re: master plan for jsr 283 query implementation
Date Tue, 11 Sep 2007 21:04:40 GMT
Marcel Reutegger wrote:
> Thomas Mueller wrote:
>>> use javacc for SQL2 parsing
>>
>> I would use a hand-written recursive descent parser. I know I'm
>> probably the only one suggesting this...
> 
> what are the advantages of a hand-written parser over a generated one?
> 
> probably performance, but are there other?

I my view the goal should be to make it as easy as possible for people to 
understand the jackrabbit code and contribute to it, without significantly 
sacrifying performance or reinventing the whole wheel. It's maybe easy to 
understand the javacc grammar once you know javacc but it still is a hurdle to 
jump the first time.
I'm still unable to contribute to the parser because I had no time yet to 
thoroughly learn javacc.
We just went back from antlr to hand-written java code for a very simple query 
language we use. The resulting code was much simpler (less code), better to 
understand and was more flexible in regards of how tokens are handled in 
different contexts. All this need not apply to JCR-SQL2. So I can't judge what 
is the best way to implement the parser.

Cheers,
Christoph


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