Combining MSFs with the continuation monad

[ivanperez-keera]

I've long had an idea of using MSFs with the continuation monad.

A while back I put this little piece of code together:

{-# LANGUAGE ExistentialQuantification #-}
{-# LANGUAGE RankNTypes                #-}
import Control.Monad.Cont
import Data.Functor.Identity
import Data.MonadicStreamFunction
import Data.MonadicStreamFunction.InternalCore

f :: MSF (Cont Bool) Int Float
f = go
  where
    go = MSF $ \x -> pure (7.0, go)

data Cont' a = forall b . Cont' (Cont (b, MSF Cont' a b) a)

evalContMSF :: MSF Cont' a b
            -> MSF Identity a b
evalContMSF msf = MSF $ \a -> do
  let Cont' cont = unMSF msf a
      (b, msf') = runCont cont id
  return (b, evalContMSF msf')

unaryOp :: Int -> Int
unaryOp = (*4)
       .> (+ 5)

(.>) = flip (.)

I never really pursued it further. I'd be glad to see others push in this direction, or figure out what great things could be done, or whether it's just completely useless.

Happy to also collaborate if that's an option for me (depends on legal issues, etc.).