liftM2

liftM2 :: Monad m => (a1 -> a2 -> r) -> m a1 -> m a2 -> m r
base Control.Monad GHC.Base, ghc-internal GHC.Internal.Base GHC.Internal.Control.Monad
Promote a function to a monad, scanning the monadic arguments from left to right.

Examples

>>> liftM2 (+) [0,1] [0,2]
[0,2,1,3]

>>> liftM2 (+) (Just 1) Nothing
Nothing

>>> liftM2 (+) (+ 3) (* 2) 5
18
liftM2 :: Monad m => (a1 -> a2 -> r) -> m a1 -> m a2 -> m r
base-compat Control.Monad.Compat, protolude Protolude.Monad, streaming Streaming, rio RIO.Prelude, base-prelude BasePrelude, classy-prelude ClassyPrelude, Cabal-syntax Distribution.Compat.Prelude, universum Universum.Monad.Reexport, ihaskell IHaskellPrelude, base-compat-batteries Control.Monad.Compat, rebase Rebase.Prelude, hledger Hledger.Cli.Script, massiv-test Test.Massiv.Utils, LambdaHack Game.LambdaHack.Core.Prelude, cabal-install-solver Distribution.Solver.Compat.Prelude, faktory Faktory.Prelude, can-i-haz Control.Monad.Except.CoHas Control.Monad.Reader.Has, vcr Imports, verset Verset, yesod-paginator Yesod.Paginator.Prelude, distribution-opensuse OpenSuse.Prelude, hledger-web Hledger.Web.Import
Promote a function to a monad, scanning the monadic arguments from left to right. For example, 
liftM2 (+) [0,1] [0,2] = [0,2,1,3]
liftM2 (+) (Just 1) Nothing = Nothing
liftM2 :: MonadParallel m => (a -> b -> c) -> m a -> m b -> m c
monad-parallel Control.Monad.Parallel
Like liftM2, but evaluating its two monadic arguments in parallel.
liftM2 :: Monad m => a1 -> a2 -> r -> m a1 -> m a2 -> m r
control-monad-free Control.Monad.Free
Promote a function to a monad, scanning the monadic arguments from left to right. For example, 
liftM2 (+) [0,1] [0,2] = [0,2,1,3]
liftM2 (+) (Just 1) Nothing = Nothing
data LiftM2
first-class-families Fcf Fcf.Combinators
type family LiftM2 (a :: a1 ~> a2 ~> r) (a4 :: m a1) (a5 :: m a2) :: m r
singletons-base Control.Monad.Singletons
liftM2' :: Monad m => (a -> b -> c) -> m a -> m b -> m c
protolude Protolude.Monad
data LiftM2Sym0 (a :: TyFun a1 ~> a2 ~> r m a1 ~> m a2 ~> m r)
singletons-base Control.Monad.Singletons
data LiftM2Sym1 (a6989586621679271130 :: a1 ~> a2 ~> r) (b :: TyFun m a1 m a2 ~> m r)
singletons-base Control.Monad.Singletons
data LiftM2Sym2 (a6989586621679271130 :: a1 ~> a2 ~> r) (a6989586621679271131 :: m a1) (c :: TyFun m a2 m r)
singletons-base Control.Monad.Singletons
type family LiftM2Sym3 (a6989586621679271130 :: a1 ~> a2 ~> r) (a6989586621679271131 :: m a1) (a6989586621679271132 :: m a2) :: m r
singletons-base Control.Monad.Singletons
sLiftM2 :: forall a1 a2 r (m :: Type -> Type) (t1 :: a1 ~> (a2 ~> r)) (t2 :: m a1) (t3 :: m a2) . SMonad m => Sing t1 -> Sing t2 -> Sing t3 -> Sing (LiftM2 t1 t2 t3)
singletons-base Control.Monad.Singletons
mrgLiftM2 :: (MonadTryMerge m, Mergeable a, Mergeable b, Mergeable c) => (a -> b -> c) -> m a -> m b -> m c
grisette Grisette.Lib.Control.Monad Grisette.Unified.Lib.Control.Monad
liftM2 with MergingStrategy knowledge propagation.