Prologue.Control.Monad.Trans

Documentation

type PrimMonadTransInvariants t m = (MonadTransInvariants t m, PrimState m ~ PrimState (t m))

type MonadTransInvariants t m = (Monad m, Monad (t m), MonadTrans t)

type family MonadTranses (ts :: [(* -> *) -> * -> *]) :: Constraint where ...

Equations

MonadTranses '[] = ()

MonadTranses (t ': ts) = (MonadTrans t, MonadTranses ts)

lift2 :: (Monad (t1 m), Monad m, MonadTranses '[t1, t2]) => m a -> t2 (t1 m) a

Warning: You should not use lift2 in production code. Use monad transformer stack instead. If you really need it in a very specific use case, use _lift2_ instead.

_lift2_ :: (Monad (t1 m), Monad m, MonadTranses '[t1, t2]) => m a -> t2 (t1 m) a

lift3 :: (Monad (t2 (t1 m)), Monad (t1 m), Monad m, MonadTranses '[t1, t2, t3]) => m a -> t3 (t2 (t1 m)) a

Warning: You should not use lift3 in production code. Use monad transformer stack instead. If you really need it in a very specific use case, use _lift3_ instead.

_lift3_ :: (Monad (t2 (t1 m)), Monad (t1 m), Monad m, MonadTranses '[t1, t2, t3]) => m a -> t3 (t2 (t1 m)) a

lift4 :: (Monad (t3 (t2 (t1 m))), Monad (t2 (t1 m)), Monad (t1 m), Monad m, MonadTranses '[t1, t2, t3, t4]) => m a -> t4 (t3 (t2 (t1 m))) a

Warning: You should not use lift4 in production code. Use monad transformer stack instead. If you really need it in a very specific use case, use _lift4_ instead.

_lift4_ :: (Monad (t3 (t2 (t1 m))), Monad (t2 (t1 m)), Monad (t1 m), Monad m, MonadTranses '[t1, t2, t3, t4]) => m a -> t4 (t3 (t2 (t1 m))) a

lift5 :: (Monad (t4 (t3 (t2 (t1 m)))), Monad (t3 (t2 (t1 m))), Monad (t2 (t1 m)), Monad (t1 m), Monad m, MonadTranses '[t1, t2, t3, t4, t5]) => m a -> t5 (t4 (t3 (t2 (t1 m)))) a

Warning: You should not use lift5 in production code. Use monad transformer stack instead. If you really need it in a very specific use case, use _lift5_ instead.

_lift5_ :: (Monad (t4 (t3 (t2 (t1 m)))), Monad (t3 (t2 (t1 m))), Monad (t2 (t1 m)), Monad (t1 m), Monad m, MonadTranses '[t1, t2, t3, t4, t5]) => m a -> t5 (t4 (t3 (t2 (t1 m)))) a

class MonadTrans (t :: (* -> *) -> * -> *) where

The class of monad transformers. Instances should satisfy the following laws, which state that lift is a monad transformation:

• lift . return = return

• lift (m >>= f) = lift m >>= (lift . f)

Minimal complete definition

lift

Methods

lift :: Monad m => m a -> t m a

Lift a computation from the argument monad to the constructed monad.

Instances

MonadTrans MaybeT

Defined in Control.Monad.Trans.Maybe

Methods

lift :: Monad m => m a -> MaybeT m a

MonadTrans Free

This is not a true monad transformer. It is only a monad transformer "up to retract".

Defined in Control.Monad.Free

Methods

lift :: Monad m => m a -> Free m a

MonadTrans Yoneda

Defined in Data.Functor.Yoneda

Methods

lift :: Monad m => m a -> Yoneda m a

MonadTrans (IdentityT :: (* -> *) -> * -> *)

Defined in Control.Monad.Trans.Identity

Methods

lift :: Monad m => m a -> IdentityT m a

MonadTrans (ExceptT e)

Defined in Control.Monad.Trans.Except

Methods

lift :: Monad m => m a -> ExceptT e m a

MonadTrans (FreeT f)

Defined in Control.Monad.Trans.Free

Methods

lift :: Monad m => m a -> FreeT f m a

Alternative f => MonadTrans (CofreeT f)

Defined in Control.Comonad.Trans.Cofree

Methods

lift :: Monad m => m a -> CofreeT f m a

MonadTrans (ErrorT e)

Defined in Control.Monad.Trans.Error

Methods

lift :: Monad m => m a -> ErrorT e m a