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From Timothy Chen <tnac...@gmail.com>
Subject Re: DrQL grammar and parser
Date Sun, 26 Aug 2012 23:02:29 GMT


Sent from my iPhone

On Aug 26, 2012, at 3:21 PM, Camuel Gilyadov <camuel@gmail.com> wrote:

> On Mon, Aug 27, 2012 at 12:22 AM, Ted Dunning <ted.dunning@gmail.com> wrote:
> 
>> Camuel,
>> 
>> Do you have a grammar test suite that demonstrates the range of
>> expressions?
>> 
> 
> I don't have an exhaustive one. But with OpenDremel I tested it with all
> sample queries given in the BQL manual and then adding my own for various
> cases. I can do similar thing here as well as develop grammar unit tests
> (with ANTLR's gunit).
> 
> 
>> 
>> Also, I believe that some have a goal to use additional languages besides
>> SQL like languages.  A limited version of pig, for instance, would be very
>> interesting.  To do this, it will be important to have a logical plan
>> structure that is common for different syntaxes and is not limited to the
>> idiosyncracies of any particular syntax.
>> 
>> How do you think that should be handled?  Do you have an idea for a logical
>> plan structure?
>> 
> 
> Yes I have, but I afraid it is a radical idea. I think queries must be
> directly compiled into generic C source code. That way in worst case, a
> completely separate compiler could be developed for some exotic query
> language and backend could be still reused. On other extreme, dialects
> could be handled in the grammar itself yielding same AST so frontend code
> should not even be aware.Between these two extremes two different grammars
> should be used, both yielding object models which could then handled by
> same code generator (so code generator is reused). Not to say that this
> approach simplifies the backend and it is most tricky part to implement as
> it must be scaled and secured and outlives single query or query session.
> 
> I think an attempt to design a logical query language expressive enough to
> cover many existing and future query languages would not be all that easy
> going...
> 
> 
>> 
>> On Sun, Aug 26, 2012 at 4:11 PM, Camuel Gilyadov <camuel@gmail.com> wrote:
>> 
>>> I've written and attached ANTLR grammar for DrQL which I assume is same
>> as
>>> BigQuery language described in Query Reference on BigQuery website. This
>>> grammar includes AST production rules.
>>> 
>>> 
>>> 
>> 

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