Re: BETWEEN SYMMETRIC/ASYMMETRIC - Mailing list pgsql-hackers

From Christopher Kings-Lynne
Subject Re: BETWEEN SYMMETRIC/ASYMMETRIC
Date
Msg-id GNELIHDDFBOCMGBFGEFOOEBFCCAA.chriskl@familyhealth.com.au
Whole thread Raw
In response to Re: BETWEEN SYMMETRIC/ASYMMETRIC  (Tom Lane <tgl@sss.pgh.pa.us>)
Responses Re: BETWEEN SYMMETRIC/ASYMMETRIC  (Tom Lane <tgl@sss.pgh.pa.us>)
Re: BETWEEN SYMMETRIC/ASYMMETRIC  (Bruce Momjian <pgman@candle.pha.pa.us>)
List pgsql-hackers
> "Christopher Kings-Lynne" <chriskl@familyhealth.com.au> writes:
> > Also, Tom (or anyone): in regards to your previous email,
> should I just go
> > back to using opt_symmetry to shorten the number of productions, since I
> > have to make them reserved words anyway?
>
> Might as well.  No point in writing more productions if it doesn't buy
> anything.

Since it's really just two ways of writing the same thing, wouldn't bison
just produce the exact same C code?  I'll rewrite it anyway for elegance,
but just wondering...

> BTW, I've forgotten whether your patch is purely syntactic or not,
> but I'd really like to see someone fix things so that BETWEEN has its
> own expression node tree type and is not expanded into some ugly
> "A>=B and A<=C" equivalent.  This would (a) allow it to be
> reverse-listed reasonably, and (b) eliminate redundant evaluations of
> the subexpressions.

It is purely syntactic.  Anyone want to give me a quick hint on how to make
a new node tree type for BETWEEN?  What does reverse-listing mean as well?

Chris



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