{-# LANGUAGE DataKinds #-} {-# LANGUAGE OverloadedStrings #-} {-# LANGUAGE TemplateHaskell #-} import Control.Monad.Logger import Options.Declarative test :: Cmd "verbosity test" () test = do $logDebug "this is debug level" $logInfo "this is info level" $logWarn "this is warn level" $logError "this is error level" main :: IO () main = run_ test