6 Apr
2007
6 Apr
'07
5:26 a.m.
On 4/5/07, Albert Y. C. Lai <trebla@vex.net> wrote:
Dan Weston wrote:
What is it called if it's both?
Then we say "the argument occurs in both positive and negative positions" or "the argument occurs in both covariant and contravariant positions". There doesn't seem to be a shorter name. I want to note that this kind of thing drives OOP crazy.
I know that types like
data T = T (T -> T)
are inhabitated by things other than bottom (like id or \_ -> undefined), but can it be useful for *anything*? Cheers, -- Felipe.