transformers-0.5.5.0: Concrete functor and monad transformers

Copyright(c) Ross Paterson 2012
LicenseBSD-style (see the file LICENSE)
Maintainer[email protected]
Stabilityexperimental
Portabilityportable
Safe HaskellSafe
LanguageHaskell98

Control.Monad.Signatures

Description

Signatures for monad operations that require specialized lifting. Each signature has a uniformity property that the lifting should satisfy.

Synopsis
  • type CallCC m a b = ((a -> m b) -> m a) -> m a
  • type Catch e m a = m a -> (e -> m a) -> m a
  • type Listen w m a = m a -> m (a, w)
  • type Pass w m a = m (a, w -> w) -> m a

Documentation

type CallCC m a b = ((a -> m b) -> m a) -> m a Source #

Signature of the callCC operation, introduced in Control.Monad.Trans.Cont. Any lifting function liftCallCC should satisfy

  • lift (f k) = f' (lift . k) => lift (cf f) = liftCallCC cf f'

type Catch e m a = m a -> (e -> m a) -> m a Source #

Signature of the catchE operation, introduced in Control.Monad.Trans.Except. Any lifting function liftCatch should satisfy

  • lift (cf m f) = liftCatch (lift . cf) (lift f)

type Listen w m a = m a -> m (a, w) Source #

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

  • lift . liftListen = liftListen . lift

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

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

  • lift . liftPass = liftPass . lift