>> I propose really basic functionality, that can be enhanced in future -
>> step by step. This proposal doesn't contain any controversial feature or
>> syntax, I hope. It is related to PLpgSQL only, but described feature can be
>> used from any PL languages with implemented interface.
> I think it would make sense to implement the interface in at least one of
> our other supported PLs. I'm not entirely clear how well this will match up
> with, say, plperl, but I'd be interested to see.
The minimalistic interface can be based on get/set functions. We can do
necessary transformations there.