Unstandard way of zipping conduits.

gistfile1.hs

import Data.Functor.Identity
import Control.Applicative
import Control.Monad
import Control.Monad.Trans
import Control.Monad.Trans.Maybe
-- From the monad-loops package
import Control.Monad.Loops 
import Data.Void
import Data.Conduit
import Data.Conduit.List

zippedSource :: Monad m => Sink a (ConduitM b Void (ConduitM () (a,b) m)) ()
zippedSource = let mpair = (,) <$> MaybeT await <*> MaybeT (lift await)
            in whileJust_ (runMaybeT mpair) $ lift . lift . yield

-- This has a scary type
zip' s1 s2 = s2 $$ (s1 $$ zippedSource)


resultList :: [(Int,Char)]
resultList = let zipped = zip' (sourceList [1, 2, 3]) (sourceList ['a', 'b', 'c'])
    in runIdentity (zipped $$ consume)