Re: proposal: new polymorphic types - commontype and commontypearray

From: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
To: Pavel Stehule <pavel(dot)stehule(at)gmail(dot)com>
Cc: Dmitry Dolgov <9erthalion6(at)gmail(dot)com>, Greg Stark <stark(at)mit(dot)edu>, David Steele <david(at)pgmasters(dot)net>, Robert Haas <robertmhaas(at)gmail(dot)com>, PostgreSQL Hackers <pgsql-hackers(at)postgresql(dot)org>
Subject: Re: proposal: new polymorphic types - commontype and commontypearray
Date: 2020-03-15 16:48:09
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Pavel Stehule <pavel(dot)stehule(at)gmail(dot)com> writes:
> Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> napsal:
>> Yeah, that's what I said. But does it really add anything beyond the
>> proposed text "A function returning a polymorphic type must have at least
>> one matching polymorphic argument"? I don't think it'd be terribly
>> helpful to say "A function returning anyelement must have at least one
>> anyelement, anyarray, anynonarray, anyenum, or anyrange argument", and
>> for sure such an error message would be a pain to maintain.

> The error message in your first patch is ok for all types without anyrange.
> A behave of this type is more strict and +/- different than from other
> polymorphic types.

Well, here's a version that does it like that, but personally I find these
messages too verbose and not an improvement on what I had before.

(This is also rebased over the stuff I committed yesterday.)

regards, tom lane

Attachment Content-Type Size
0001-refactoring-2.patch text/x-diff 24.3 KB
0002-add-anycompatible-2.patch text/x-diff 60.8 KB

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