From: | William White <bwhite(at)frognet(dot)net> |
---|---|
To: | Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> |
Cc: | pgsql-general(at)postgresql(dot)org |
Subject: | Re: Question about rtrees (overleft replacing left in nodes) |
Date: | 2004-03-31 21:21:19 |
Message-ID: | 406B364F.2040000@frognet.net |
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Lists: | pgsql-general pgsql-patches |
Tom Lane wrote:
> Right, but what about the existing operators --- what is a more correct
> way to document them?
Ouch.
Appealing to J.F. Allen's terminology ("An Interval-Based Representation
of Temporal Knowledge", Comm ACM 26(11) 832-43), overleft could be
called "left or finishes" (implying all other related conditions, of
which there are a bunch) but this relies too heavily on time notation I
think. "right boundary left of right boundary" is accurate but rather
verbose, "rightoverleft" too confusing. Of course, I suspect most
people will see the operator, not the C function name; if they see the
latter they can read the code anyway.
Perhaps document as S &< T iff S "does not extend to the right
of/beyond" (the right boundary of) T? And either leave the C functions
as-is or give them reasonable names; in either case, "a.high.x <=
b.high.x" is just as clear as any comment.
-- Bill
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