-- Hoogle documentation, generated by Haddock
-- See Hoogle, http://www.haskell.org/hoogle/


-- | Tiny library to replace classic if/else
--   
@package RichConditional
@version 0.1.0.0

module Control.RichConditional

-- | Instances of this class provide a test on some type a with an
--   alternative case for when it fails. If it passes, it gives a value of
--   type b; otherwise, it gives a value of type c.
class TotalIf a b c
decide :: TotalIf a b c => a -> Decision b c

-- | Instances of this class provide a test on some type a. If it passes,
--   it gives a value of type b; otherwise, it gives Nothing.
class PartialIf a b
indicate :: PartialIf a b => a -> Indication b

-- | A conditional using a TotalIf instance. This is just like the function
--   <a>either</a> which decomposes an Either, except that the Either is
--   produced through a TotalIf instance determined by the types of the
--   cases.
ifElse :: TotalIf a b c => a -> (b -> d) -> (c -> d) -> d

-- | A conditional using a PartialIf instance. This is just like the
--   function <a>maybe</a> which decomposes a Maybe, except that the Maybe
--   is produced through an PartialIf instance determined by the type of
--   the positive case.
inCase :: PartialIf a b => a -> (b -> c) -> c -> c

-- | Like <a>guard</a> but with a bonus: if the condition passes, you
--   actually get a hold of some new information.
ensure :: (Monad m, MonadPlus m, PartialIf a b) => a -> m b

-- | Like <a>ensure</a> but for the positive case (Left) of a TotalIf.
--   Requires a proxy on the negative type in order to disambiguate.
ensurePositive :: (Monad m, MonadPlus m, TotalIf a b c) => a -> u c -> m b

-- | Like <a>ensure</a> but for the negative case (Right) of a TotalIf.
--   Requires a proxy on the positive type in order to disambiguate.
ensureNegative :: (Monad m, MonadPlus m, TotalIf a b c) => a -> u b -> m c
instance TotalIf (Either a b) a b
instance PartialIf (Maybe a) a