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

On Fri, Jan 26, 2024 at 4:55 PM Sutou Kouhei <kou@clear-code.com> wrote:
>
> Hi,
>
> In <CAEG8a3KhS6s1XQgDSvc8vFTb4GkhBmS8TxOoVSDPFX+MPExxxQ@mail.gmail.com>
>   "Re: Make COPY format extendable: Extract COPY TO format implementations" on Fri, 26 Jan 2024 16:41:50 +0800,
>   Junwang Zhao <zhjwpku@gmail.com> wrote:
>
> > CopyToProcessOption()/CopyFromProcessOption() can only handle
> > single option, and store the options in the opaque field,  but it can not
> > check the relation of two options, for example, considering json format,
> > the `header` option can not be handled by these two functions.
> >
> > I want to find a way when the user specifies the header option, customer
> > handler can error out.
>
> Ah, you want to use a built-in option (such as "header")
> value from a custom handler, right? Hmm, it may be better
> that we call CopyToProcessOption()/CopyFromProcessOption()
> for all options including built-in options.
>
Hmm, still I don't think it can handle all cases, since we don't know
the sequence of the options, we need all the options been parsed
before we check the compatibility of the options, or customer
handlers will need complicated logic to resolve that, which might
lead to ugly code :(

>
> Thanks,
> --
> kou



--
Regards
Junwang Zhao