Ron Mayer <ron@cheapcomplexdevices.com> writes:
> Would formatting functions for intervals such as...
> to_iso8601basic_char(interval) -- return ISO-8601 basic fmt interval
> to_iso8601basic_char(timestamp) -- return ISO-8601 basic fmt date/time
> would be better than a new GUC variable?
I could see arguments for both --- in the timestamp world we have
DateStyle to control the default output format, plus to_char when you
want something different. I'd suggest continuing with your plan of
providing GUC control over the default interval format (just use a
separate GUC variable, please, for orthogonality). If you want to add
an explicit formatting function later, you can do that too.
BTW, I do not recall exactly why Karel wants to deprecate
to_char(interval), but I don't think it's because of any fundamental
objection to the notion of a formatting function. I think it was
because the present definition is badly designed and needs to be
replaced with a different API.
regards, tom lane
