Control.Failure

| failure-0.1.0.1: A simple type class for success/failure computations. | Contents | Index
Control.Failure
Contents
Type class Wrapping failures Convenience `String` failure Convert `Failure`s into concrete types
Description
Type classes for returning failures.
Synopsis
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
type Error f
try :: Failure (Error f) f' => f a -> f' a
data NothingException = NothingException
data NullException = NullException
Type class
class Monad f => Failure e f where
Methods
failure :: e -> f v
Instances
Exception e => Failure e IO |
Failure e [] |
Failure e Maybe |
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
newtype StringException
Constructors
StringException String |
Instances
Show StringException |
Typeable StringException |
Exception StringException |
failureString :: Failure StringException m => String -> m a
Call `failure` with a `String`.
Convert `Failure`s into concrete types
class Try f where
Associated Types
type Error f
Methods
try :: Failure (Error f) f' => f a -> f' a
Instances
Try [] |
Try Maybe |
Try (Either e) |
data NothingException
Constructors
NothingException |
Instances
Show NothingException |
Typeable NothingException |
Exception NothingException |
data NullException
Constructors
NullException |
Instances
Show NullException |
Typeable NullException |
Exception NullException |
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