| Copyright | Copyright (c) 2008--2015 wren gayle romano |
|---|---|
| License | BSD |
| Maintainer | wren@community.haskell.org |
| Stability | perpetually unstable |
| Portability | semi-portable (MPTCs) |
| Safe Haskell | Safe-Inferred |
| Language | Haskell98 |
Control.Monad.State.UnificationExtras
Contents
Description
This module defines some extra functions for Control.Monad.State.Lazy. This package really isn't the proper place for these, but we need them to be somewhere.
TODO: patch transformers/mtl-2 with these functions.
Synopsis
- liftReader :: Reader e a -> State e a
- liftReaderT :: Monad m => ReaderT e m a -> StateT e m a
- modify' :: MonadState s m => (s -> s) -> m ()
- localState :: MonadState s m => m a -> m a
Additional functions for MTL
liftReader :: Reader e a -> State e a Source #
Lift a reader into a state monad. More particularly, this
allows disabling mutability in a local context within State.
liftReaderT :: Monad m => ReaderT e m a -> StateT e m a Source #
Lift a reader into a state monad. More particularly, this
allows disabling mutability in a local context within StateT.
modify' :: MonadState s m => (s -> s) -> m () Source #
A strict version of modify.
localState :: MonadState s m => m a -> m a Source #
Run a state action and undo the state changes at the end.