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{-# LANGUAGE NoImplicitPrelude #-}
{-# OPTIONS_HADDOCK not-home #-}
-- | Maybe type
module GHC.Maybe
( Maybe (..)
)
where
import GHC.Num.Integer () -- See Note [Depend on GHC.Num.Integer] in GHC.Base
import GHC.Classes
default ()
-------------------------------------------------------------------------------
-- Maybe type
-------------------------------------------------------------------------------
-- | The 'Maybe' type encapsulates an optional value. A value of type
-- @'Maybe' a@ either contains a value of type @a@ (represented as @'Just' a@),
-- or it is empty (represented as 'Nothing'). Using 'Maybe' is a good way to
-- deal with errors or exceptional cases without resorting to drastic
-- measures such as 'Prelude.error'.
--
-- The 'Maybe' type is also a monad. It is a simple kind of error
-- monad, where all errors are represented by 'Nothing'. A richer
-- error monad can be built using the 'Data.Either.Either' type.
--
data Maybe a = Nothing | Just a
deriving ( Eq -- ^ @since 2.01
, Ord -- ^ @since 2.01
)
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