Question

我最近完成了我学校所需的蛇和梯子游戏，但我的同伴可以完美地编译这段代码而我一遍又一遍地得到同样的错误。我尝试了很多不同的方法，但我不确定还能做些什么。

我尝试下载Haskell的早期版本，但没有帮助。我还使用“cabal安装镜头”安装了镜头包，并使用ghci导入了Control.Lens包 - ＆gt;在编译程序之前导入Control.Lens。

当我尝试编译代码时，出现以下错误。文件名是Main.hs

ghc -o main Main.hs
[1 of 1] Compiling Main               ( Main.hs, Main.o )

Main.hs:6:1: parse error on input module

我也在下面附上我的代码。感谢任何愿意提供帮助的人。

module Main where

import Data.List
import Data.Sequence
import Data.Foldable
import Control.Lens

data Game = G Int Int Int [Int] [Bool] [Bool] [Bool] [Int] [Property] Int
data Property = Int | E | A | D
displayRow game@(G rows cols nplayers pos e a d drolls props turn) n = unlines [ '+' : concat (replicate n "---+") , '|' : concat (replicate n "   |")]
display game@(G 0 cols nplayers pos e a d drolls props turn) = ""
display game@(G rows cols nplayers pos e a d drolls props turn) = (displayRow game cols) ++ display (G (rows - 1) cols nplayers pos e a d drolls props turn)
go game@(G rows cols nplayers pos e a d drolls props 0) _ = display game
go game@(G rows cols nplayers pos e a d drolls props turn) i
  | elem (rows*cols) pos = display game 
  | nplayers == i = go (G rows cols nplayers pos e a d drolls props (turn - 1)) 0 
  | otherwise = go (move (G rows cols nplayers pos' e a d (tail drolls) props turn) i roll) (i + 1) where
    roll = if d!!i then 2*(head drolls) else (head drolls)
move (G rows cols nplayers pos e a d drolls props turn) i j = case (elemIndex posij pos) of
  Just k -> (move (G rows cols nplayers pos' e' a' d' drolls props turn) k 1) 
  Nothing -> (G rows cols nplayers pos' e' a' d' drolls props turn) 
  where
    posij = if (pos!!i + j) > rows*cols then rows*cols else pos!!i + j 
    pos'
      | props!!posij > posij = if e!!i then pos & ix i .~ (2*(props!!posij) - posij) else pos & ix i .~ (props!!posij)
      | props!!posij < posij = if a!!i then pos & ix i .~ posij else pos & ix i .~ (props!!posij)
      | otherwise = pos & ix i .~ posij
    e'
      | props!!posij > posij = if e!!i then e & ix i .~ False else e
      | props!!posij == E = e & ix i .~ True
      | otherwise = e
    a'
      | props!!posij < posij = if a!!i then a & ix i .~ False else a
      | props!!posij == A = a & ix i .~ True
      | otherwise = a
    d' = if (props!!posij) == D then (d & ix i .~ True) else (d & ix i .~ False)
instance Show Game where
  show game@(G rows cols nplayers pos e a d drolls props turn) = go game 0 
build (l:ls) = build' (G 0 0 0 [] [] [] [] [] [] 0) (l:ls) where
  build' game (l:ls) = build' (update game l) ls
  build' game [] = game
  update (G rows cols nplayers pos e a d drolls props turn) s = case (words s) of
                    "board":l -> G (nums!!0) (nums!!1) nplayers pos e a d drolls [i | i <- [0..(nums!!0)*(nums!!1)]] turn
                    "players":l -> G rows cols (nums!!0) [0 | _ <- [1..(nums!!0)]] [False | _ <- [1..(nums!!0)]] [False | _ <- [1..(nums!!0)]] [False | _ <- [1..(nums!!0)]] drolls props turn
                    "dice":l -> G rows cols nplayers pos e a d (cycle nums) props turn
                    "ladder":l -> G rows cols nplayers pos e a d drolls (props & ix (nums!!0) .~ (nums!!1)) turn
                    "snake":l -> G rows cols nplayers pos e a d drolls (props & ix (nums!!0) .~ (nums!!1)) turn
                    "powerup":"escalator":l -> G rows cols nplayers pos e a d drolls (over (elements (flip elem nums)) (const E) props) turn
                    "powerup":"antivenom":l -> G rows cols nplayers pos e a d drolls (over (elements (flip elem nums)) (const A) props) turn
                    "powerup":"double":l -> G rows cols nplayers pos e a d drolls (over (elements (flip elem nums)) (const D) props) turn
                    "turns":l -> G rows cols nplayers pos e a d nums props (turn + (nums!!0)) where
                      nums = map read l :: [Int]
readFrom input = build (lines input)
main = do
  input <- getContents
  putStr $ show $ readFrom input

Answer 1

module行必须高于导入
不需要在模块行where之后缩进所有内容
在每个函数/数据decl / instance之间添加一个空行以便于阅读
在每个功能上提供类型签名
在写完之前不要等待编译，你应该逐步编译和测试，这样你就可以轻松地修复设计缺陷
使用-Wall标记进行编译，为您提供有关可提高可读性的更改的合理建议

一旦你将其清理成可行的状态，你就可以看到你得到了什么类型的错误，并努力修复它们。

Haskell - 获得多个解析错误

1 个答案: