Control.Monad.Trans.Lift.Pass

Lifting the pass operation.

Documentation

class MonadTrans t => LiftPass t where

The class of monad transformers capable of lifting pass.

Methods

liftPass :: Monad m => Pass w m (StT t a) -> Pass w (t m) a

Lift the pass operation. Should satisfy the uniformity property

• lift . liftPass = liftPass . lift

Instances

LiftPass MaybeT

LiftPass IdentityT

Monoid w' => LiftPass (WriterT w')

Monoid w' => LiftPass (WriterT w')

LiftPass (ExceptT e)

LiftPass (StateT s)

LiftPass (StateT s)

LiftPass (ReaderT r)

Monoid w' => LiftPass (RWST r w' s)

Monoid w' => LiftPass (RWST r w' s)

type Pass w m a = m (a, w -> w) -> m a

Signature of the pass operation, introduced in Control.Monad.Trans.Writer. Any lifting function liftPass should satisfy

• lift . liftPass = liftPass . lift

defaultLiftPass

Arguments

:: (Monad m, LiftPass n)

=> (forall x. n m x -> t m x)

Monad constructor

-> (forall o x. t o x -> n o x)

Monad deconstructor

-> Pass w m (StT n a)

-> Pass w (t m) a

Default definition for the liftPass method.

module Control.Monad.Trans.Class