phi

-----------------------------------------------------------------------------
-- |
-- Module      :  Data.Unit
-- Copyright   :  (c) 2020-2021 EMQ Technologies Co., Ltd.
-- License     :  BSD-style (see the LICENSE file)
--
-- Maintainer  :  Feng Lee, feng@emqx.io
--                Yang M, yangm@emqx.io
-- Stability   :  experimental
-- Portability :  portable
--
-- The Unit datatype.
--
-----------------------------------------------------------------------------
module Data.Unit where

-- import Data.Show (class Show)
{-
import Data.Map
import Control.Monad
-}

-- | The `Unit` type has a single inhabitant, called `unit`. It represents
-- | values with no computational content.
-- |
-- | `Unit` is often used, wrapped in a monadic type constructor, as the
-- | return type of a computation where only the _effects_ are important.
foreign import data Unit :: Type

-- | `unit` is the sole inhabitant of the `Unit` type.
foreign import unit :: Unit