Re: Boolean operators without commutators vs. ALL/ANY

From: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
To: Robert Haas <robertmhaas(at)gmail(dot)com>
Cc: Florian Pflug <fgp(at)phlo(dot)org>, PG Hackers <pgsql-hackers(at)postgresql(dot)org>
Subject: Re: Boolean operators without commutators vs. ALL/ANY
Date: 2011-06-13 13:49:49
Message-ID: 15471.1307972989@sss.pgh.pa.us
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Robert Haas <robertmhaas(at)gmail(dot)com> writes:
> On Sun, Jun 12, 2011 at 11:44 PM, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:
>> There are syntactic reasons not to do that. It'd be a lot easier just
>> to provide a commutator operator for ~.

> Details?

Well, for one, it becomes unobvious what

A op ANY (B) op C

means. This has come up before, and I seem to recall that we identified
some more-compelling problems, but that's the best I can do before
consuming any caffeine.

In any case, if you dig around enough to notice all the infrastructure
that's involved with this, you'll definitely come to the conclusion that
it'd be a lot less work to just add the missing commutator operators.

regards, tom lane

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