temporary functions (and other object types)

Hi,

A customer of ours has the need for temporary functions.  The use case
is writing test cases for their databases: the idea being that their
code creates a temp function which then goes away automatically at
session end, just like a temp table.  It's said that this makes things
generally easier for the test harness.

Other object types that would also be useful to have as temp-able are
types, domains and casts; and perhaps (if someone sees a need)
aggregates and operators.  Other objects are not necessary, but if
someone thinks that some more stuff should be made temp-able, we'd try
to go for as general a solution as possible.  But these aren't critical;
functions are the main pain point.

I haven't looked at the code at all to see how this would be
implemented; I'm basically asking whether there would be objections to
having this feature in core.

-- 
Álvaro Herrera <alvherre@alvh.no-ip.org>