control-monad-failure-mtl (empty) → 0.5.0

raw patch · 5 files changed

+150/−0 lines, 5 filesdep +basedep +mtlsetup-changed

Dependencies added: base, mtl

Files

• Control/Monad/Failure.hs +3/−0
• Control/Monad/Failure/Class.hs +39/−0
• Control/Monad/Failure/MTL.hs +80/−0
• Setup.hs +2/−0
• control-monad-failure-mtl.cabal +26/−0

@@ -0,0 +1,3 @@+module Control.Monad.Failure (module Control.Monad.Failure.Class) where++import Control.Monad.Failure.Class

@@ -0,0 +1,39 @@+{-# LANGUAGE Rank2Types #-}+{-# LANGUAGE DeriveDataTypeable #-}+{-# LANGUAGE FlexibleContexts #-}+{-| Defines the class @MonadFailure@ for monads which can fail.+-}+module Control.Monad.Failure.Class where++import Control.Exception (throw, Exception)+import Data.Typeable++class Monad m => MonadFailure e m where+    failure :: e -> m a++class MonadFailure e m => WrapFailure e m where+    -- | 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.+    wrapFailure :: (forall eIn. Exception eIn => eIn -> e) -> m a -> m a++-- --------------+-- base instances+-- --------------++instance MonadFailure e Maybe where failure _ = Nothing+instance MonadFailure e []    where failure _ = []++instance Exception e => MonadFailure e IO where+  failure = Control.Exception.throw++-- | Call 'failure' with a 'String'.+failureString :: MonadFailure StringException m => String -> m a+failureString = failure . StringException++newtype StringException = StringException String+    deriving Typeable+instance Show StringException where+    show (StringException s) = "StringException: " ++ s+instance Exception StringException

@@ -0,0 +1,80 @@+{-# LANGUAGE MultiParamTypeClasses #-}+{-# LANGUAGE UndecidableInstances #-}+{-# LANGUAGE FlexibleInstances #-}+{-# OPTIONS_GHC -fno-warn-orphans #-}++module Control.Monad.Failure.MTL (module Control.Monad.Failure.Class) where++import Control.Monad.Failure.Class++import Control.Monad.Error+import Control.Monad.List+import Control.Monad.Reader+import Control.Monad.State.Lazy     as Lazy+import Control.Monad.State.Strict   as Strict+import Control.Monad.Writer.Lazy    as Lazy+import Control.Monad.Writer.Strict  as Strict+import Control.Monad.RWS.Lazy       as Lazy+import Control.Monad.RWS.Strict     as Strict+import Data.Monoid++-- -----------------------+-- MonadFailure Instances+-- -----------------------++instance (Error e) => MonadFailure e (Either e) where+  failure = Left++instance (Error e, Monad m) => MonadFailure e (ErrorT e m) where+  failure = throwError++instance MonadFailure e m => MonadFailure e (ListT m) where+  failure = lift . failure++instance MonadFailure e m => MonadFailure e (ReaderT r m) where+  failure = lift . failure++instance (Monoid w, MonadFailure e m) => MonadFailure e (Lazy.WriterT w  m) where+  failure = lift . failure++instance MonadFailure e m => MonadFailure e (Lazy.StateT s m) where+  failure = lift . failure++instance (Monoid w, MonadFailure e m) => MonadFailure e (Lazy.RWST r w s m) where+  failure = lift . failure++instance (Monoid w, MonadFailure e m) => MonadFailure e (Strict.WriterT w  m) where+  failure = lift . failure++instance MonadFailure e m => MonadFailure e (Strict.StateT s m) where+  failure = lift . failure++instance (Monoid w, MonadFailure e m) => MonadFailure e (Strict.RWST r w s m) where+  failure = lift . failure++-- ---------------------+-- WrapFailure instances+-- ---------------------++instance WrapFailure e m => WrapFailure e (ListT m) where+  wrapFailure f = ListT . wrapFailure f . runListT++instance WrapFailure e m => WrapFailure e (ReaderT r m) where+  wrapFailure f m = ReaderT $ \r -> wrapFailure f (runReaderT m r)++instance (WrapFailure e m, Monoid w) => WrapFailure e (Lazy.WriterT w m) where+  wrapFailure f = Lazy.WriterT . wrapFailure f . Lazy.runWriterT+++-- all the following instances require undecidable instances+instance WrapFailure e m => WrapFailure e (Lazy.StateT s m) where+  wrapFailure f m = Lazy.StateT $ \s -> wrapFailure f (Lazy.runStateT m s)++instance (WrapFailure e m, Monoid w) => WrapFailure e (Lazy.RWST r w s m) where+  wrapFailure f m = Lazy.RWST $ \r s -> wrapFailure f (Lazy.runRWST m r s)++instance WrapFailure e m => WrapFailure e (Strict.StateT s m) where+  wrapFailure f m = Strict.StateT $ \s -> wrapFailure f (Strict.runStateT m s)++instance (WrapFailure e m, Monoid w) => WrapFailure e (Strict.RWST r w s m) where+  wrapFailure f m = Strict.RWST $ \r s -> wrapFailure f (Strict.runRWST m r s)

@@ -0,0 +1,2 @@+import Distribution.Simple+main = defaultMain

@@ -0,0 +1,26 @@+name: control-monad-failure-mtl+version: 0.5.0+Cabal-Version:  >= 1.6+build-type: Simple+license: PublicDomain+author: Pepe Iborra, Michael Snoyman, Nicolas Pouillard+maintainer: pepeiborra@gmail.com+homepage: http://github.com/pepeiborra/control-monad-failure+description: A class for monads which can fail with an error.+synopsis: A class for monads which can fail with an error.+category: Control, Monads+stability: experimental++Library+  buildable: True+  build-depends: base >= 4 && < 5, mtl+  ghc-options: -Wall+  extensions:  MultiParamTypeClasses, FlexibleInstances+  exposed-modules:+     Control.Monad.Failure+     Control.Monad.Failure.Class+     Control.Monad.Failure.MTL++source-repository head+  type:     git+  location: git://github.com/pepeiborra/control-monad-failure.git