75 lines
1.7 KiB
Haskell
75 lines
1.7 KiB
Haskell
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{-# LANGUAGE LambdaCase #-}
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module Internal.Karel where
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import Internal.Types
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import Internal.World
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data Karel = Karel
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{ karelPosition :: Vector,
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karelDirection :: Direction,
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karelBeepers :: Int,
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karelWorld :: World
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}
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deriving (Show, Eq)
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stepVector :: Direction -> Vector
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stepVector = \case
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North -> (0, 1)
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East -> (1, 0)
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South -> (0, -1)
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West -> (-1, 0)
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leftTurn :: Direction -> Direction
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leftTurn = \case
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North -> West
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West -> South
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South -> East
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East -> North
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changeBeepers :: Int -> Karel -> Karel
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changeBeepers db robot
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| checkedCount <= 0 = error ("There are no beepers to " ++ msg)
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| otherwise =
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robot
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{ karelBeepers = inBag + db,
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karelWorld = setBeepersAt position (atPosition - db) world
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}
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where
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(position, world) = (karelPosition robot, karelWorld robot)
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inBag = karelBeepers robot
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atPosition = getBeepersAt position world
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(checkedCount, msg) =
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if db == 1 then (atPosition, "pick up") else (inBag, "put down")
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defaultKarel :: World -> Karel
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defaultKarel world =
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Karel
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{ karelPosition = (1, 1),
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karelDirection = East,
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karelBeepers = 0,
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karelWorld = world
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}
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initialPosition :: Vector -> Karel -> Karel
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initialPosition pos robot
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| not $ positionWithinWorld (karelWorld robot) pos = error "Invalid position"
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| otherwise =
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robot
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{ karelPosition = pos
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}
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initialDirection :: Direction -> Karel -> Karel
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initialDirection dir robot =
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robot
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{ karelDirection = dir
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}
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initialBeepersInBag :: Int -> Karel -> Karel
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initialBeepersInBag beepers robot
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| beepers < 0 = error "Invalid count of beepers"
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| otherwise =
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robot
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{ karelBeepers = beepers
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}
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