Re: BETWEEN SYMMETRIC/ASYMMETRIC

From: "Christopher Kings-Lynne" <chriskl(at)familyhealth(dot)com(dot)au>
To: "Tom Lane" <tgl(at)sss(dot)pgh(dot)pa(dot)us>
Cc: "Gavin Sherry" <swm(at)linuxworld(dot)com(dot)au>, "Hackers" <pgsql-hackers(at)postgresql(dot)org>
Subject: Re: BETWEEN SYMMETRIC/ASYMMETRIC
Date: 2002-04-11 03:00:11
Message-ID: GNELIHDDFBOCMGBFGEFOOEBFCCAA.chriskl@familyhealth.com.au
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> "Christopher Kings-Lynne" <chriskl(at)familyhealth(dot)com(dot)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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