Re: Rethinking plpgsql's assignment implementation

On 12/11/20 12:21, Tom Lane wrote:
> solution I adopted was just to invent a new CoercionContext value
> COERCION_PLPGSQL, representing "use pl/pgsql's rules".  (Basically
> what that means nowadays is to apply CoerceViaIO if assignment cast
> lookup doesn't find a cast pathway.)

That seems like a rule that might be of use in other PLs or extensions;
could it have a more generic name, COERCION_FALLBACK or something?

> is now quoted, but the "SET n:" bit in front of it might confuse people,
> especially if we don't document this new syntax (which I'm inclined not
> to, since it's useless in straight SQL).

If it's true that the only choices for n: are 1: or 2:, maybe it would look
less confusing in an error message to, hmm, decree that this specialized SET
form /always/ takes a two-component name, but accept something special like
ROUTINE.x (or UNNAMED.x or NULL.x or something) for the case where there
isn't a qualifying label in the plpgsql source?

It's still a strange arbitrary creation, but might give more of a hint of
its meaning if it crops up in an error message somewhere.

Regards,
-Chap