Control.Monad.Error.Map

This module provides generic functions set useful for errortype-parameterized monads and monad transformers, such as Get. Example:

pSign :: Parser (Maybe Char) Bool
pSign = do
  c <- pChar ?>> return Nothing
  case c of
    '+' -> return False
    '-' -> return True
    x -> throwError (Just x)

pSignedNumber :: Parser String Int
pSignedNumber = do
  is_negative <- fromMaybe False <$> option'' pSign
  value <- foldl1 (\ !a !b -> a * 10 + b) <$> many1'' pDigit ?>> return "digit or sign expected"
  return $ if is_negative then -value else value

Documentation

class (MonadError e m_e, MonadError e' m_e') => MonadMapError e m_e e' m_e' | m_e -> e, m_e' -> e', m_e e' -> m_e', m_e' e -> m_e where

Minimal complete definition

mapError

Methods

mapError :: (e -> e') -> m_e a -> m_e' a

Instances

MonadMapError e (Either e) e' (Either e')

Defined in Control.Monad.Error.Map

Methods

mapError :: (e -> e') -> Either e a -> Either e' a

Monad m => MonadMapError e (ExceptT e m) e' (ExceptT e' m)

Defined in Control.Monad.Error.Map

Methods

mapError :: (e -> e') -> ExceptT e m a -> ExceptT e' m a

MonadMapError e m_e e' m_e' => MonadMapError e (ConduitT i o m_e) e' (ConduitT i o m_e')

Defined in Control.Monad.Error.Map

Methods

mapError :: (e -> e') -> ConduitT i o m_e a -> ConduitT i o m_e' a

Monad m => MonadMapError e (GetC s i e m) e' (GetC s i e' m)

Defined in Data.Conduit.Parsers.GetC

Methods

mapError :: (e -> e') -> GetC s i e m a -> GetC s i e' m a

(?=>>) :: (MonadMapError e m_e (Either e e') m_Either_e_e', MonadMapError Void m_Void (Either e e') m_Either_e_e', MonadMapError (Either e e') m_Either_e_e' e' m_e') => m_e a -> (e -> m_Void e') -> m_e' a infixl 1

(?>>) :: (MonadMapError () m_Unit (Maybe e) m_Maybe_e, MonadMapError Void m_Void (Maybe e) m_Maybe_e, MonadMapError (Maybe e) m_Maybe_e e m_e) => m_Unit a -> m_Void e -> m_e a infixl 1

option'' :: (MonadPlus m_Unit, MonadMapError e m_e () m_Unit, MonadMapError () m_Unit e' m_e') => m_e a -> m_e' (Maybe a)

many'' :: (MonadPlus m_Unit, MonadMapError e m_e () m_Unit, MonadMapError () m_Unit e' m_e') => m_e a -> m_e' [a]

many1'' :: (MonadPlus m_Unit, MonadMapError e m_e () m_Unit, MonadMapError () m_Unit e m_e) => m_e a -> m_e (NonEmpty a)

manyTill'' :: (MonadPlus m_Unit, MonadMapError e' m_e' () m_Unit, MonadMapError () m_Unit e m_e) => m_e a -> m_e' b -> m_e [a]

sepBy'' :: (MonadPlus m_Unit, MonadMapError e m_e () m_Unit, MonadMapError () m_Unit e'' m_e'', MonadMapError e' m_e' () m_Unit, MonadMapError () m_Unit () m_Unit) => m_e a -> m_e' s -> m_e'' [a]

sepBy1'' :: (MonadPlus m_Unit, MonadMapError e m_e () m_Unit, MonadMapError () m_Unit e m_e, MonadMapError e' m_e' () m_Unit, MonadMapError () m_Unit () m_Unit) => m_e a -> m_e' s -> m_e (NonEmpty a)

skipMany'' :: (MonadPlus m_Unit, MonadMapError e m_e () m_Unit, MonadMapError () m_Unit e' m_e') => m_e a -> m_e' ()

skipMany1'' :: (MonadPlus m_Unit, MonadMapError e m_e () m_Unit, MonadMapError () m_Unit e m_e) => m_e a -> m_e ()