=?ISO-8859-2?Q?pasman_pasma=F1ski?= <pasman(dot)p(at)gmail(dot)com> writes:
> I propose to add "accumulative" flag to a function definition. This
> flag would be set for function f(x) which is accumulative and
> immutable.
Maybe you'd better define what you mean by "accumulative" ...
> This flag allows to use an index on x for clauses containing f(x):
> where f(x) = const
> where f(x) > const
... because it's sure not clear how you would get that to work.
regards, tom lane