1
2
3
4
5
6
7
8
9
data Promise f a = PendingPromise f | ResolvedPromise a | BrokenPromise deriving (Show)
instance Monad (Promise f) where
return a = ResolvedPromise a
BrokenPromise >>= _ = BrokenPromise
PendingPromise a >>= _ = PendingPromise a
ResolvedPromise a >>= f = f a
main = putStr "Compiled!"
XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
runghc main.cpp

Compiled!