gistfile1.hs

{-# LANGUAGE TemplateHaskell #-}
{-# LANGUAGE MultiParamTypeClasses #-}
{-# LANGUAGE DefaultSignatures #-}
{-# LANGUAGE TypeFamilies #-}
{-# LANGUAGE FunctionalDependencies #-}
module MonadBase where

import Language.Haskell.TH

class (Monad m, Monad t) => MonadBase m t | t -> m where
  liftBase :: m a -> t a
  default liftBase :: (m ~ t) => m a -> t a
  liftBase = id

makeMonadBase :: Name -> Q [Dec]
makeMonadBase n = return
  [ InstanceD
      []
      (AppT (AppT (ConT ''MonadBase) (ConT n)) (ConT n))
      []
  ]

{-# LANGUAGE TemplateHaskell #-}
{-# LANGUAGE MultiParamTypeClasses #-}
module Main where

import MonadBase

makeMonadBase ''IO

main :: IO ()
main = liftBase $ putStrLn "You lift me UP!!!!"