Greatest/Least functions?

As far as I can tell, Postgres has no equivalent to greatest and least
functions in Oracle.  Yes, you can do the same thing with a case statement,
but at the expense of writing MUCH longer SQL statements.

Is this something that is on or can be added to the 'to do' list?

I could write a series of user-defined functions to do specific
comparisons (such as comparing several dates and returning the greatest
one) but there doesn't appear to be a way to write a user function with a
variable number of parameters, either, so I guess I'd have to define a
series of them with 2,3,4,... parameters.
--
Mike Nolan