+++ /dev/null
-module a10
-
-import StdEnv
-
-import Data.Functor
-import Control.Applicative
-import Control.Monad
-import Data.Maybe
-import Data.Error
-
-:: BM a b = {t :: a->b, f :: b->a, t2 :: A.c t:(t c a)->t c b, f2 :: A.c t:(t b c)->t a c}
-bm = {t = id, f = id, t2 = id, f2 = id}
-
-:: Action b a
- = MoveToShip (BM b High) (BM a High)
- | MoveToQuay (BM b High) (BM a High)
- | MoveUp (BM b Low) (BM a High)
- | MoveDown (BM b High) (BM a Low)
- | Lock (BM b Low) (BM a Low)
- | Unlock (BM b Low) (BM a Low)
- | Wait (BM b a)
- | E.i: (:.) infixl 1 (Action b i) (Action i a)
- | WhileContainerBelow (BM b a) (Action a a)
-:: High = High
-:: Low = Low
-
-moveToShip = MoveToShip bm bm
-moveToQuay = MoveToQuay bm bm
-moveUp = MoveUp bm bm
-moveDown = MoveDown bm bm
-lock = Lock bm bm
-unlock = Unlock bm bm
-wait = Wait bm
-whileContainerBelow = WhileContainerBelow bm
-
-:: State =
- { onShip :: [String]
- , onQuay :: [String]
- , craneUp :: Bool
- , craneOnQuay :: Bool
- , locked :: Maybe String
- }
-
-state0 =
- { onShip = []
- , onQuay = ["apples","beer","camera's"]
- , craneUp = True
- , craneOnQuay = True
- , locked = Nothing
- }
-
-// ================
-:: Sem a = Sem ((MaybeErrorString State) -> MaybeErrorString State)
-
-
-eval :: (Action i f) State -> MaybeErrorString State
-eval (MoveToShip b1 b2) s = pure {s & craneOnQuay = False}
-eval (MoveToQuay b1 b2) s = pure {s & craneOnQuay = True}
-eval (MoveUp b1 b2) s = pure {s & craneUp = True}
-eval (MoveDown b1 b2) s = pure {s & craneUp = False}
-eval (Lock b1 b2) s=:{locked=Nothing}
- | s.craneOnQuay =
- =
-eval (Lock b1 b2) s=:{locked=Nothing} = Error ("Cannot lock new container, craner contains " + container)
-eval (Lock b1 b2) s=:{locked=(Just _)} = Error ("Cannot lock new container, craner contains " + container)
- Nothing
- | s.craneOnQuay
- = case s.onQuay of
- [c:r] = pure {s & onQuay = r, locked = Just c}
- [] = Error "Cannot lock container on empty quay"
- = case s.onShip of
- [c:r] = pure {s & onShip = r, locked = Just c}
- [] = Error "Cannot lock container on empty ship"
- Just container
- = Error ("Cannot lock new container, craner contains " + container)
-eval (Unlock b1 b2) s =case s.locked of
- Just container | s.craneOnQuay
- = Result {s & onQuay = [container:s.onQuay], locked = Nothing}
- = Result {s & onShip = [container:s.onShip], locked = Nothing}
- Nothing = Error "Cannot unlock container, craner contains nothing"
- Wait bm = Result s
- a :. b = eval b (eval a r)
- WhileContainerBelow bm action
- | s.craneOnQuay && not (isEmpty s.onQuay) ||
- not s.craneOnQuay && not (isEmpty s.onShip)
- = eval (action :. WhileContainerBelow bm action) r
- = r
-*/
-
-Start = 42