使用IO与Ncurses的
问题描述:
我想使用UI.NCurses使用IO与Ncurses的
https://john-millikin.com/software/haskell-ncurses/reference/haskell-ncurses/latest/
对于一些简单的寻路教训 的问题是我有一个随机的诠释,当然它返回一个IO诠释 然后手段我有一个IO TerrianType然后导致一个IO阵列TerrianType
问题是我需要解决这些在主要,所以他们可以打印到屏幕使用drawString。我包括下面的代码:我想你混淆了[IO TerrianType]
和IO [TerrianType]
module Main where
2 import UI.NCurses
3 import Control.Monad
4 import Control.Monad.IO.Class
5 import System.Random
6
7 -- Tutorials
8 -- working on several path findng algorithims
9 -- http://www.redblobgames.com/pathfinding/a-star/introduction.html
10
11 -- | The 'Compass' data type provides breadcrumbs from the goal to the start.
12 data Compass = N | S | E | W deriving (Show, Eq)
13
14 -- | 'Cartogram' is a structure of compass directions that mirrors the terrian.
15 type Cartogram = [Compass]
16
17 -- | 'TerrianType' determines how hard a cell is to traverse.
18 data TerrianType = Sand | Forest | Goal deriving (Show, Eq)
19
20 -- | 'Terrian' is a collection of TerrianTypes with a single goal.
21 type Terrian = [IO TerrianType]
22
23 -- | 'roll' gets a random int from 1 to the parameter
24 roll :: Int -> IO Int
25 roll m
26 | m <= 0 = getStdRandom (randomR (1,1))
27 | m > 0 = getStdRandom (randomR (1,m))
28
29 -- | 'getRandomTerrian' gets a random TerrianType
30 getRandomTerrian :: IO TerrianType
31 getRandomTerrian = do
32 r <- roll 3
33 case r of
34 1 -> return Forest
35 2 -> return Sand
36 3 -> return Goal
37 _ -> return Sand
38
39 -- | 'constructTerrian' constructs a Terrian array of random TerrianTypes
40 constructTerrian :: Int -> Int -> Terrian
41 constructTerrian n1 n2 = take (n1 * n2) $ repeat getRandomTerrian
42
43 drawShow a = (drawString . show) a
44
45 --showString :: t -> String
46 --showString t = show t
47
48 main :: IO()
49 main = do
50 runCurses $ do
51 setEcho False
52 w <- defaultWindow
53 updateWindow w $ do
54 moveCursor 1 1
55 mapM drawShow (constructTerrian 5 5)
56 render
57 waitFor w (\ev -> ev == EventCharacter 'q' || ev == EventCharacter 'Q')58
59 waitFor :: Window -> (Event -> Bool) -> Curses()
60 waitFor w p = loop where
61 loop = do
62 ev <- getEvent w Nothing
63 case ev of
64 Nothing -> loop
65 Just ev' -> if p ev' then return() else loop
• No instance for (Show (IO TerrianType))
arising from a use of ‘drawShow’
• In the first argument of ‘mapM’, namely ‘drawShow’
In a stmt of a 'do' block: mapM drawShow (constructTerrian 5 5)
In the second argument of ‘($)’, namely
‘do { moveCursor 1 1;
mapM drawShow (constructTerrian 5 5) }’
答
。
在您的代码中,您生成了一个[IO TerrianType]
,它是IO操作的列表。当你mapM
那,你必须运行如果你想访问他们的TerrianType
并打印它的行动。
所以,你可能需要像
drawShow :: (IO TerrianType) -> IO()
drawShow a = a >>= drawString . show
但是,我不知道是否[IO TerrianType]
是开始用正确的事情。除了使用
constructTerrian :: Int -> Int -> [IO TerrianType]
,你现在正在做的,你应该移到
constructTerrian :: Int -> Int -> IO [TerrianType]
,并相应地修改代码。第一个代码不计算随机值,但仅返回将滚动随机值的IO操作列表。也许你现在想要滚动它们,并产生一个值列表,正如第二种类型所暗示的那样。
嘿泰克斯我会给那一枪。不知道我是否可以做IO [TerrianType],因为IO来自随机Int,但会尝试 – liminal18
是:无法匹配预期类型'IO Terrian' 与实际类型'[IO TerrianType]' •在表达式中:采取(n1 * n2)$重复getRandomTerrian – liminal18
好越来越近谢谢。 – liminal18