Re: Question about rtrees (overleft replacing left in nodes) - Mailing list pgsql-general

From William White
Subject Re: Question about rtrees (overleft replacing left in nodes)
Date
Msg-id 406B364F.2040000@frognet.net
Whole thread Raw
In response to Question about rtrees (overleft replacing left in nodes)  ("bwhite" <bwhite@frognet.net>)
List pgsql-general
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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