Implement Show instance for Karel #3

Manually merged
mfocko merged 2 commits from show-instance into main 2020-11-15 16:56:55 +01:00
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@ -15,6 +15,10 @@ data Karel = Karel
}
deriving (Eq)
xor :: Bool -> Bool -> Bool
xor True a = not a
xor False a = a
getHeader :: Karel -> String
getHeader karel = unlines [
printf " %8s %s %s %s" "POSITION" "FACING" "BEEP-BAG" "BEEP-POS",
@ -50,32 +54,27 @@ mapCell karel x y
| otherwise = " . "
where beepersAt = getBeepersAt (x, y) $ karelWorld karel
mapWall :: Karel -> Int -> Int -> String
mapWall karel x y = leftPart <> rightPart
where
world = karelWorld karel
(width, height) = worldDimensions world
wallAtNorth = hasWallAt (x, y) North world
vWallAbove = hasWallAt (x, y + 1) East world
vWallBelow = hasWallAt (x, y - 1) East world
vWallAt = hasWallAt (x, y) East world
verticalWall = vWallAt && vWallAbove
wallEnds = wallAtNorth && (not $ hasWallAt (x + 1, y) North world)
wallStarts = wallAtNorth && x > 1 && (not $ hasWallAt (x - 1, y) North world)
noVWall = not (hasWallAt (x, y) West world || hasWallAt (x, y + 1) West world)
(northWall:eastWall:westWall:_) = map (\d -> hasWallAt (x, y) d world) [North, East, West]
(northWallOnLeft:northWallOnRight:_) = map (\d -> hasWallAt (x + d, y) North world) [-1, 1]
(eastWallAbove:westWallAbove:_) = map (\d -> hasWallAt (x, y + 1) d world) [East, West]
verticalWall = eastWall && eastWallAbove
wallEnds = northWall && not northWallOnRight
wallStarts = northWall && x > 1 && not northWallOnLeft
leftPart
| wallStarts && noVWall = "+-"
| wallAtNorth = "--"
| wallStarts && not (westWall || westWallAbove) = "+-"
| northWall = "--"
| otherwise = " "
rightPart
| wallAtNorth && wallEnds && verticalWall = "-|"
| wallEnds = "-+"
| wallAtNorth && (vWallAbove) = "-+"
| wallAtNorth = "--"
| verticalWall && hasWallAt (x+1, y) North world = " +"
| northWall && wallEnds && verticalWall = "-|"
| wallEnds || (northWall && eastWallAbove) = "-+"
| northWall = "--"
| (verticalWall && northWallOnRight) || (eastWall `xor` eastWallAbove) = " +"
| verticalWall = " |"
| not vWallAbove && vWallAt = " +"
| not vWallAt && vWallAbove = " +"
| otherwise = " "
getRow :: Karel -> Int -> String
@ -89,7 +88,7 @@ getRow karel row
mapWall karel column row
| column <- [1..width]
]
line = (printf "%2d |" row) <> foldl1 (<>) [
line = printf "%2d |" row <> foldl1 (<>) [
position <> wall
| column <- [1..width],
let wall = if hasWallAt (column, row) East world then "|" else " ",