Control.Monad.Supply.Class

See Control.Monad.Supply for documentation.

Documentation

class Monad m => MonadSupply s f m | m -> s, m -> f where

The MonadSupply class provides access to the functions needed to construct supply-consuming computations in a monad transformer stack.

Methods

supply :: (s -> f a) -> m a

Supply a construction function with an s value from the supply, the f in the function's type refers to the monad wrapped by SupplyT.

provide :: (s -> a) -> m a

Provide a non-monadic construction function with an s value from the supply and automatically lift its result into the f monad that SupplyT wraps.

Instances

MonadSupply s f m => MonadSupply s f (MaybeT m)

MonadSupply s f m => MonadSupply s f (ListT m)

MonadSupply s f m => MonadSupply s f (IdentityT m)

(Monoid w, MonadSupply s f m) => MonadSupply s f (WriterT w m)

(Monoid w, MonadSupply s f m) => MonadSupply s f (WriterT w m)

MonadSupply s f m => MonadSupply s f (StateT s m)

MonadSupply s f m => MonadSupply s f (StateT s m)

MonadSupply s f m => MonadSupply s f (ReaderT r m)

(Error e, MonadSupply s f m) => MonadSupply s f (ErrorT e m)

MonadSupply s f m => MonadSupply s f (ContT r m)

(Functor m, Monad m) => MonadSupply s m (SupplyT s m)

(Monoid w, MonadSupply s f m) => MonadSupply s f (RWST r w s m)

(Monoid w, MonadSupply s f m) => MonadSupply s f (RWST r w s m)

demand :: MonadSupply s f m => m s

Demand an s value from the supply.