failure-0.1.0.1: A simple type class for success/failure computations. Source code Contents Index

Control.Failure

Contents Type class Wrapping failures Convenience String failure Convert Failures 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 Source

Methods failure :: e -> f v Source Instances Exception e => Failure e IO Failure e [] Failure e Maybe

Wrapping failures

class Failure e f => WrapFailure e f where Source

Methods wrapFailure :: (forall eIn. Exception eIn => eIn -> e) -> f a -> f a Source 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 Source

Constructors StringException String Instances Show StringException Typeable StringException Exception StringException

failureString :: Failure StringException m => String -> m a Source

Call failure with a String.

Convert Failures into concrete types

class Try f where Source

Associated Types type Error f Source Methods try :: Failure (Error f) f' => f a -> f' a Source Instances Try [] Try Maybe Try (Either e)

data NothingException Source

Constructors NothingException Instances Show NothingException Typeable NothingException Exception NothingException

data NullException Source

Constructors NullException Instances Show NullException Typeable NullException Exception NullException

Produced by Haddock version 2.6.0