| Copyright | (C) 2016-2025 David M. Johnson (@dmjio) |
|---|---|
| License | BSD3-style (see the file LICENSE) |
| Maintainer | David M. Johnson <code@dmj.io> |
| Stability | experimental |
| Portability | non-portable |
| Safe Haskell | Safe-Inferred |
| Language | Haskell2010 |
Miso.State
Description
Similar to how one manages state in React,
miso applications manage state with the State monad.
The State Monad works well with MonadState lenses as seen in Lens and the lens library.
updateModel :: Action -> Effect Model Action updateModel (AddOne event) = do modify (+1) io_ (consoleLog "Added One!")
This module re-exports select combinators from RWS and serves as a placeholder to add new state management combinators.
Synopsis
- ask :: MonadReader r m => m r
- modify :: MonadState s m => (s -> s) -> m ()
- modify' :: MonadState s m => (s -> s) -> m ()
- get :: MonadState s m => m s
- gets :: MonadState s m => (s -> a) -> m a
- put :: MonadState s m => s -> m ()
- tell :: MonadWriter w m => w -> m ()
Documentation
ask :: MonadReader r m => m r #
Retrieves the monad environment.
modify :: MonadState s m => (s -> s) -> m () #
Monadic state transformer.
Maps an old state to a new state inside a state monad. The old state is thrown away.
Main> :t modify ((+1) :: Int -> Int)
modify (...) :: (MonadState Int a) => a ()This says that modify (+1) acts over any
Monad that is a member of the MonadState class,
with an Int state.
modify' :: MonadState s m => (s -> s) -> m () #
A variant of modify in which the computation is strict in the
new state.
Since: mtl-2.2
get :: MonadState s m => m s #
Return the state from the internals of the monad.
gets :: MonadState s m => (s -> a) -> m a #
Gets specific component of the state, using a projection function supplied.
put :: MonadState s m => s -> m () #
Replace the state inside the monad.
tell :: MonadWriter w m => w -> m () #
tell ww.