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From: Tom Lane <tgl@sss.pgh.pa.us>
To: Paul Ramsey <pramsey@cleverelephant.ca>
cc: PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>
Subject: Re: Allowing extensions to supply operator-/function-specific info
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Comments: In-reply-to Paul Ramsey <pramsey@cleverelephant.ca>
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Paul Ramsey <pramsey@cleverelephant.ca> writes:
> I had what seemed to be working code except for a couple rare cases,
> but when I fixed those cases it turned out that I had a major problem:
> building a <var> OP <const> expression works fine, but building a
> <const> OP <var> expression returns me an error.

Yup, you're not supposed to do that.  The output expression *must* have
the index key on the left, it's up to you to commute the operator if
needed to make that happen.

			regards, tom lane