app.hs

runStoryApp :: Comonad w => StoryApp a -> CoStoryAppT w b -> (a, b)
runStoryApp = pairEffect (,)

runStory :: Comonad w => Story a -> CoStoryT w b -> (a, b)
runStory = pairEffect (,)

mkCoStoryApp :: Comonad w
             => w b
             -> (w b -> Character -> ChangeType -> w b)
             -> (forall x y . (forall a. Story a -> b)
                           -> w b
                           -> StoryApp x
                           -> StoryApp y
                           -> w b)
             -> (w b -> w b)
             -> CoStoryAppT w b
mkCoStoryApp start changeH interruptH macguffinH =
    fix $ flip coiterT start . next . flip runStoryApp
  where
    next run w =
        CoStoryF
            (changeH w)
            (interruptH (unsafeCoerce run) w)
            (macguffinH w)

mkCoStory :: Comonad w
          => w b
          -> (w b -> Character -> ChangeType -> (ChangeResult, w b))
          -> (forall x y . (forall a. Story a -> (a, b))
                        -> w b
                        -> Story x
                        -> Story y
                        -> (y, w b))
          -> (w b -> (Desirable, w b))
          -> CoStoryT w b
mkCoStory start changeH interruptH macguffinH =
    fix $ flip coiterT start . next . flip runStory
  where
    next run w =
        CoStoryF
            (changeH w)
            (interruptH (unsafeCoerce run) w)
            (macguffinH w)