| Safe Haskell | Safe |
|---|---|
| Language | Haskell98 |
Control.Failure
Description
Type classes for returning failures.
- class Monad f => Failure e f where
- failure :: e -> f v
- class Failure e f => WrapFailure e f where
- wrapFailure :: (forall eIn. Exception eIn => eIn -> e) -> f a -> f a
- newtype StringException = StringException String
- failureString :: Failure StringException m => String -> m a
- class Try f where
- data NothingException = NothingException
- data NullException = NullException
Type class
Wrapping failures
class Failure e f => WrapFailure e f where
Methods
wrapFailure :: (forall eIn. Exception eIn => eIn -> e) -> f a -> f a
Wrap the failure value, if any, with the given function. This is useful in particular when you want all the exceptions returned from a certain library to be of a certain type, even if they were generated by a different library.
Instances
| Exception e => WrapFailure e IO |
Convenience String failure
failureString :: Failure StringException m => String -> m a