| Safe Haskell | None |
|---|---|
| Language | Haskell2010 |
Foundation.Monad
- class Monad m => MonadIO m where
- class Monad m => MonadFailure m where
- class Monad m => MonadThrow m where
- class MonadThrow m => MonadCatch m where
- class MonadCatch m => MonadBracket m where
- generalBracket :: m a -> (a -> b -> m ignored1) -> (a -> SomeException -> m ignored2) -> (a -> m b) -> m b
- class MonadTrans trans where
- newtype Identity a :: * -> * = Identity {
- runIdentity :: a
Documentation
class Monad m => MonadFailure m where
Monad that can represent failure
Similar to MonadFail but with a parametrized Failure linked to the Monad
Associated Types
type Failure m
The associated type with the MonadFailure, representing what failure can be encoded in this monad
Instances
| MonadFailure Maybe | |
| MonadFailure (Either a) | |
| MonadFailure m => MonadFailure (ReaderT r m) | |
| (Functor m, MonadFailure m) => MonadFailure (StateT s m) | |
| MonadFailure m => MonadFailure (Conduit i o m) | |
| Monad state => MonadFailure (Builder collection mutCollection step state err) |
class Monad m => MonadThrow m where
Monad that can throw exception
Methods
throw :: Exception e => e -> m a
Throw immediatity an exception.
Only a MonadCatch monad will be able to catch the exception using catch
Instances
| MonadThrow IO | |
| MonadThrow m => MonadThrow (ResourceT m) | |
| MonadThrow m => MonadThrow (ReaderT r m) | |
| (Functor m, MonadThrow m) => MonadThrow (StateT s m) | |
| MonadThrow m => MonadThrow (Conduit i o m) |
class MonadThrow m => MonadCatch m where
Monad that can catch exception
Instances
| MonadCatch IO | |
| MonadCatch m => MonadCatch (ResourceT m) | |
| MonadCatch m => MonadCatch (ReaderT r m) | |
| (Functor m, MonadCatch m) => MonadCatch (StateT s m) | |
| MonadCatch m => MonadCatch (Conduit i o m) |
class MonadCatch m => MonadBracket m where
Monad that can ensure cleanup actions are performed even in the case of exceptions, both synchronous and asynchronous. This usually excludes continuation-based monads.
Methods
Arguments
| :: m a | acquire some resource |
| -> (a -> b -> m ignored1) | cleanup, no exception thrown |
| -> (a -> SomeException -> m ignored2) | cleanup, some exception thrown. The exception will be rethrown |
| -> (a -> m b) | inner action to perform with the resource |
| -> m b |
A generalized version of the standard bracket function which allows distinguishing different exit cases.
Instances
| MonadBracket IO | |
| MonadBracket m => MonadBracket (ResourceT m) |
class MonadTrans trans where
Basic Transformer class
Methods
lift :: Monad m => m a -> trans m a
Lift a computation from an inner monad to the current transformer monad
Instances
| MonadTrans ResourceT | |
| MonadTrans (ReaderT r) | |
| MonadTrans (StateT s) | |
| MonadTrans (Conduit i o) |
newtype Identity a :: * -> *
Identity functor and monad. (a non-strict monad)
Since: 4.8.0.0
Constructors
| Identity | |
Fields
| |
Instances
| Monad Identity | |
| Functor Identity | |
| MonadFix Identity | |
| Applicative Identity | |
| Foldable Identity | |
| Traversable Identity | |
| Generic1 Identity | |
| MonadZip Identity | |
| Eq a => Eq (Identity a) | |
| Data a => Data (Identity a) | |
| Ord a => Ord (Identity a) | |
| Read a => Read (Identity a) | This instance would be equivalent to the derived instances of the
|
| Show a => Show (Identity a) | This instance would be equivalent to the derived instances of the
|
| Generic (Identity a) | |
| type Rep1 Identity = D1 D1Identity (C1 C1_0Identity (S1 S1_0_0Identity Par1)) | |
| type Rep (Identity a) = D1 D1Identity (C1 C1_0Identity (S1 S1_0_0Identity (Rec0 a))) |