Re: Make COPY format extendable: Extract COPY TO format implementations

Hi,

In <CAD21AoDkoGL6yJ_HjNOg9cU=aAdW8uQ3rSQOeRS0SX85LPPNwQ@mail.gmail.com>
  "Re: Make COPY format extendable: Extract COPY TO format implementations" on Fri, 8 Dec 2023 15:42:06 +0900,
  Masahiko Sawada <sawada.mshk@gmail.com> wrote:

> So a custom COPY extension would not be able to define SQL functions
> just like arrow(internal) for example. We might need to define a rule
> like the function returning copy_in/out_handler must be defined as
> <method name>_to(internal) and <method_name>_from(internal).

We may not need to add "_to"/"_from" suffix by checking both
of argument type and return type. Because we use different
return type for copy_in/out_handler.

But the current LookupFuncName() family doesn't check return
type. If we use this approach, we need to improve the
current LookupFuncName() family too.


Thanks,
-- 
kou