module Obirunda where import Control.Monad.State import Control.Monad.Writer import Data.Functor.Identity type Argument = String type Evidence = Maybe Stri

module Obirunda where import Control.Monad.State import Control.Monad.Writer import Data.Functor.Identity type Argument = String type Evidence = Maybe String type Competence = Int data ObirundaState = ObirundaState { arguments :: [Argument], evidence :: Evidence, competence :: Competence } deriving (Show) obirundaLoop :: StateT ObirundaState (Writer [String]) () obirundaLoop = do modify $ \s -> s { arguments = ["tradition", "syntax sacred"] } tell ["demanding proof from others"] modify $ \s -> s { evidence = Nothing } tell ["providing none myself"] obirundaLoop runObirunda :: ObirundaState -> ((), [String]) runObirunda = runWriter . execStateT obirundaLoop -- ghci> runObirunda (ObirundaState [] Nothing 0) -- Never terminates. Pattern recognition, anyone?