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


-- | Composable, hierarchical errors.
--   
--   An Applicative Functor with error accumulation. Built in tree like
--   error type meant for gathering and reporting errors to users.
@package error-or
@version 0.1.0.0


-- | Provides composable and hierarchical errors, with pretty printing. The
--   errors are accumulated in a tree like structure, <a>ErrorAcc</a>.
--   <a>ErrorAcc</a> is disigned to be read by humans, via <a>pretty</a>,
--   not dispatched on by code. Using <a>toE</a> to convert an
--   <a>ErrorOr</a> to IO throws (in case it holds an error) a
--   <a>PrettyErrAcc</a> that uses <a>pretty</a> in the show instance.
module Data.ErrorOr

-- | Use 'Applicative'\'s <a>sequenceA</a> and <tt>sequenceA_</tt> to
--   compose <a>ErrorOr</a>s as opposed to <a>Monad</a> derived functions
--   like <a>sequence</a>.
newtype ErrorOr a
ErrorOr :: Either ErrorAcc a -> ErrorOr a
[errorOrToEither] :: ErrorOr a -> Either ErrorAcc a

-- | Could be defined as 'err = fail . Text.pack'
err :: Text -> ErrorOr a

-- | Annotate the error with context information.
tag :: Text -> ErrorOr a -> ErrorOr a
pattern Error :: ErrorAcc -> ErrorOr a
pattern OK :: a -> ErrorOr a
isOK :: ErrorOr a -> Bool
isError :: ErrorOr a -> Bool

-- | Like <tt>fromRight</tt>
fromOK :: ErrorOr a -> a

-- | Convert between functors that hold error info.
class ErrorConv t s
toE :: ErrorConv t s => t a -> s a
data ErrorAcc
Message :: Text -> ErrorAcc
List :: Seq ErrorAcc -> ErrorAcc
Tag :: Text -> ErrorAcc -> ErrorAcc

-- | Pretty print the error.
pretty :: Int -> ErrorAcc -> Text

-- | A wrapper over <a>ErrorAcc</a> to provide human readable exceptions.
--   (Exception class' displayException does not seem to be used by GHC)
--   <a>https://stackoverflow.com/questions/55490766/why-doesn-t-ghc-use-my-displayexception-method</a>
newtype PrettyErrAcc
PrettyErrAcc :: ErrorAcc -> PrettyErrAcc
[unPrettyErrAcc] :: PrettyErrAcc -> ErrorAcc
instance Data.Traversable.Traversable Data.ErrorOr.ErrorOr
instance Data.Foldable.Foldable Data.ErrorOr.ErrorOr
instance GHC.Base.Functor Data.ErrorOr.ErrorOr
instance GHC.Classes.Ord a => GHC.Classes.Ord (Data.ErrorOr.ErrorOr a)
instance GHC.Classes.Eq a => GHC.Classes.Eq (Data.ErrorOr.ErrorOr a)
instance GHC.Read.Read a => GHC.Read.Read (Data.ErrorOr.ErrorOr a)
instance GHC.Show.Show a => GHC.Show.Show (Data.ErrorOr.ErrorOr a)
instance GHC.Classes.Ord Data.ErrorOr.ErrorAcc
instance GHC.Classes.Eq Data.ErrorOr.ErrorAcc
instance GHC.Read.Read Data.ErrorOr.ErrorAcc
instance GHC.Show.Show Data.ErrorOr.ErrorAcc
instance Data.ErrorOr.ErrorConv Data.ErrorOr.ErrorOr GHC.Types.IO
instance Data.ErrorOr.ErrorConv GHC.Maybe.Maybe Data.ErrorOr.ErrorOr
instance GHC.Show.Show Data.ErrorOr.PrettyErrAcc
instance GHC.Exception.Type.Exception Data.ErrorOr.PrettyErrAcc
instance GHC.Base.Applicative Data.ErrorOr.ErrorOr
instance GHC.Base.Semigroup a => GHC.Base.Semigroup (Data.ErrorOr.ErrorOr a)
instance (GHC.Base.Semigroup (Data.ErrorOr.ErrorOr a), GHC.Base.Monoid a) => GHC.Base.Monoid (Data.ErrorOr.ErrorOr a)
instance GHC.Base.Monad Data.ErrorOr.ErrorOr
instance Control.Monad.Fail.MonadFail Data.ErrorOr.ErrorOr
instance GHC.Base.Semigroup Data.ErrorOr.ErrorAcc