-----------------------------------------------------------------------------
-- |
-- Module      :  System.Env
-- 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 System Environment module.
--
-----------------------------------------------------------------------------
module System.Env where

import Data.Maybe (Maybe)
import Data.Unit (Unit)
import Control.Monad (IO)

-- | Get all the the environment variables.
foreign import getAllEnv :: IO (List (String, String))

-- | Get the value of the environment variable.
foreign import getEnv :: String -> IO String

-- | Lookup the value of the environment variable,
-- return Nothing if there is no such value.
foreign import lookupEnv :: String -> IO (Maybe String)

-- | Set the environment variable to value.
foreign import setEnv :: String -> String -> IO ()

-- | Unset the environment variable.
foreign import unsetEnv :: String -> IO ()