freer tests

Main.hs

{-# LANGUAGE GADTs #-}
{-# LANGUAGE FlexibleContexts #-}
{-# LANGUAGE TypeOperators #-}
{-# LANGUAGE DataKinds #-}



module Main where


import Control.Monad.Freer
import Control.Monad.Freer.Reader
import Control.Monad.Freer.State


main :: IO ()
main = do
  print $ run $ flip runReader "go" $ runState (foo "blah") 4


foo :: String -> Eff '[State Int, Reader String] Bool
foo str = do
  v <- get
  s <- ask

  if s == "go"
     then put (2 :: Int)
     else return ()

  if v > (3  :: Int)
     then return True
     else return False