hoist-error 0.2.0.1 → 0.2.1.0

raw patch · 3 files changed

+71/−51 lines, 3 filesdep ~basePVP: major bump suggested

API removals or changes: PVP suggests a major version bump

Dependency ranges changed: base

API changes (from Hackage documentation)

Files

• changelog.md +5/−0
• hoist-error.cabal +1/−1
• src/Control/Monad/Error/Hoist.hs +65/−50

@@ -1,3 +1,8 @@+0.2.1.0++* Removed unicode syntax and variables+* Added Control.Monad.Error.Hoist.hoistErrorM (= flip (<%!?>))+ 0.2.0.1  * Import `eitherT` when using old EitherT instance.

@@ -1,5 +1,5 @@ name:                hoist-error-version:             0.2.0.1+version:             0.2.1.0 synopsis:            Some convenience facilities for hoisting errors into a monad description:         Provides a typeclass and useful combinators for hoisting errors into a monad. license:             MIT

@@ -3,7 +3,7 @@ {-# LANGUAGE FunctionalDependencies #-} {-# LANGUAGE GADTs                  #-} {-# LANGUAGE MultiParamTypeClasses  #-}-{-# LANGUAGE UnicodeSyntax          #-}+ -- | 'HoistError' extends 'MonadError' with 'hoistError', which enables lifting -- of partiality types such as 'Maybe' and @'Either' e@ into the monad. --@@ -34,6 +34,7 @@  module Control.Monad.Error.Hoist   ( HoistError(..)+  , hoistErrorM   , (<%?>)   , (<%!?>)   , (<?>)@@ -63,95 +64,109 @@ -- information carried by the partiality type @t@, and @e'@ represents the type -- of error expected in the monad @m@. ---class Monad m ⇒ HoistError m t e e' | t → e where+class Monad m => HoistError m t e e' | t -> e where -  -- | Given a conversion from the error in @t α@ to @e'@, we can hoist the+  -- | Given a conversion from the error in @t a@ to @e'@, we can hoist the   -- computation into @m@.   --   -- @-  -- hoistError :: 'MonadError' e m -> (() -> e) -> 'Maybe'       a -> m a-  -- hoistError :: 'MonadError' e m -> (a  -> e) -> 'Either'  a   b -> m b-  -- hoistError :: 'MonadError' e m -> (a  -> e) -> 'ExceptT' a m b -> m b+  -- 'hoistError' :: 'MonadError' e m -> (() -> e) -> 'Maybe'       a -> m a+  -- 'hoistError' :: 'MonadError' e m -> (a  -> e) -> 'Either'  a   b -> m b+  -- 'hoistError' :: 'MonadError' e m -> (a  -> e) -> 'ExceptT' a m b -> m b   -- @   hoistError-    ∷ (e → e')-    → t α-    → m α+    :: (e -> e')+    -> t a+    -> m a -instance MonadError e m ⇒ HoistError m Maybe () e where+instance MonadError e m => HoistError m Maybe () e where   hoistError f = maybe (throwError $ f ()) return -instance MonadError e' m ⇒ HoistError m (Either e) e e' where+instance MonadError e' m => HoistError m (Either e) e e' where   hoistError f = either (throwError . f) return  #if MIN_VERSION_either(5,0,0) -- Control.Monad.Trans.Either was removed from @either@ in version 5. #else-instance (m ~ n, MonadError e' m) ⇒ HoistError m (EitherT e n) e e' where+instance (m ~ n, MonadError e' m) => HoistError m (EitherT e n) e e' where   hoistError f = eitherT (throwError . f) return #endif  #if MIN_VERSION_mtl(2,2,2)-instance MonadError e' m ⇒ HoistError m (Except e) e e' where+instance MonadError e' m => HoistError m (Except e) e e' where   hoistError f = either (throwError . f) return . runExcept -instance MonadError e' m ⇒ HoistError m (ExceptT e m) e e' where+instance MonadError e' m => HoistError m (ExceptT e m) e e' where   hoistError f = either (throwError . f) return <=< runExceptT #else -- 'ErrorT' was renamed to 'ExceptT' in mtl 2.2.2-instance MonadError e' m ⇒ HoistError m (ErrorT e m) e e' where+instance MonadError e' m => HoistError m (ErrorT e m) e e' where   hoistError f = either (throwError . f) return <=< runErrorT #endif +-- | A version of 'hoistError' that operates on values already in the monad.+--+-- @+-- 'hoistErrorM' :: 'MonadError' e m => (() -> e) -> m ('Maybe'       a) ->           m a+-- 'hoistErrorM' :: 'MonadError' e m => (a  -> e) -> m ('Either'  a   b) ->           m b+-- 'hoistErrorM' :: 'MonadError' e m => (a  -> e) ->    'ExceptT' a m b  -> 'ExceptT' a m b+-- @+hoistErrorM+  :: HoistError m t e e'+  => (e -> e')+  -> m (t a)+  -> m a+hoistErrorM e m = do+  x <- m+  hoistError e x+ -- | A flipped synonym for 'hoistError'. -- -- @--- '<%?>' :: 'MonadError' e m => 'Maybe'       a -> (() -> e) ->             m a--- '<%?>' :: 'MonadError' e m => 'Either'  a   b -> (a  -> e) ->             m b--- '<%?>' :: 'MonadError' e m => 'ExceptT' a m b -> (a  -> e) -> 'ExceptT' a m b+-- ('<%?>') :: 'MonadError' e m => 'Maybe'       a -> (() -> e) ->           m a+-- ('<%?>') :: 'MonadError' e m => 'Either'  a   b -> (a  -> e) ->           m b+-- ('<%?>') :: 'MonadError' e m => 'ExceptT' a m b -> (a  -> e) -> 'ExceptT' a m b -- @ (<%?>)-  ∷ HoistError m t e e'-  ⇒ t α-  → (e → e')-  → m α+  :: HoistError m t e e'+  => t a+  -> (e -> e')+  -> m a (<%?>) = flip hoistError  infixl 8 <%?> {-# INLINE (<%?>) #-} --- | A version of '<%?>' that operates on values already in the monad.+-- | A flipped synonym for 'hoistErrorM'. -- -- @--- '<%!?>' :: 'MonadError' e m => m ('Maybe'       a) -> (() -> e) ->             m a--- '<%!?>' :: 'MonadError' e m => m ('Either'  a   b) -> (a  -> e) ->             m b--- '<%!?>' :: 'MonadError' e m =>    'ExceptT' a m b  -> (a  -> e) -> 'ExceptT' a m b+-- ('<%!?>') :: 'MonadError' e m => m ('Maybe'       a) -> (() -> e) ->           m a+-- ('<%!?>') :: 'MonadError' e m => m ('Either'  a   b) -> (a  -> e) ->           m b+-- ('<%!?>') :: 'MonadError' e m =>    'ExceptT' a m b  -> (a  -> e) -> 'ExceptT' a m b -- @ (<%!?>)-  ∷ HoistError m t e e'-  ⇒ m (t α)-  → (e → e')-  → m α-m <%!?> e = do-  x ← m-  x <%?> e+  :: HoistError m t e e'+  => m (t a)+  -> (e -> e')+  -> m a+(<%!?>) = flip hoistErrorM  infixl 8 <%!?> {-# INLINE (<%!?>) #-} --- | A version of 'hoistError' that ignores the error in @t α@ and replaces it--- with a new one in @e'@.+-- | A version of '<%?>' that ignores the error in @t a@ and replaces it+-- with a new one. -- -- @--- '<?>' :: 'MonadError' e m => 'Maybe'       a -> e ->             m a--- '<?>' :: 'MonadError' e m => 'Either'  a   b -> e ->             m b--- '<?>' :: 'MonadError' e m => 'ExceptT' a m b -> e -> 'ExceptT' a m b+-- ('<?>') :: 'MonadError' e m => 'Maybe'       a -> e ->           m a+-- ('<?>') :: 'MonadError' e m => 'Either'  a   b -> e ->           m b+-- ('<?>') :: 'MonadError' e m => 'ExceptT' a m b -> e -> 'ExceptT' a m b -- @ (<?>)-  ∷ HoistError m t e e'-  ⇒ t α-  → e'-  → m α+  :: HoistError m t e e'+  => t a+  -> e'+  -> m a m <?> e = m <%?> const e  infixl 8 <?>@@ -160,17 +175,17 @@ -- | A version of '<?>' that operates on values already in the monad. -- -- @--- '<!?>' :: 'MonadError' e m => m ('Maybe'       a) -> e ->             m a--- '<!?>' :: 'MonadError' e m => m ('Either'  a   b) -> e ->             m b--- '<!?>' :: 'MonadError' e m =>    'ExceptT' a m b  -> e -> 'ExceptT' a m b+-- ('<!?>') :: 'MonadError' e m => m ('Maybe'       a) -> e ->           m a+-- ('<!?>') :: 'MonadError' e m => m ('Either'  a   b) -> e ->           m b+-- ('<!?>') :: 'MonadError' e m =>    'ExceptT' a m b  -> e -> 'ExceptT' a m b -- @ (<!?>)-  ∷ HoistError m t e e'-  ⇒ m (t α)-  → e'-  → m α+  :: HoistError m t e e'+  => m (t a)+  -> e'+  -> m a m <!?> e = do-  x ← m+  x <- m   x <?> e  infixl 8 <!?>