不可见的压痕错误导致GHCi中的负载故障

Question

我遇到了棘手的缩进造成的问题,这里的代码看起来 是VI:

  1 import Data.List
  2 myQuickSort [] = []
  3 myQuickSort (x:xs) = myQuickSort smaller ++ [x] ++ myQuickSort bigger
  4     where   smaller = filter ( < x ) xs
  5             bigger  = filter ( >=x ) xs

但是在./cat 3.hs之后,看起来,

root@pierr-desktop:/opt/playGround/haskell# cat 3.hs 
import Data.List
myQuickSort [] = []
myQuickSort (x:xs) = myQuickSort smaller ++ [x] ++ myQuickSort bigger
    where   smaller = filter ( < x ) xs
                    bigger  = filter ( >=x ) xs

然后将其加载到ghci中

GHCi, version 6.8.2: http://www.haskell.org/ghc/  :? for help
Loading package base ... linking ... done.
Prelude> :l 3.hs
[1 of 1] Compiling Main             ( 3.hs, interpreted )

3.hs:5:11: parse error on input `='
Failed, modules loaded: none.
Prelude> 

编程haskell时如何捕获这个不可见的缩进错误？

编辑:这样写,错误就会出现.它是一种推荐的方式来编写where binding - 把变量放在不同的行中吗？

   myQuickSort [] = []
   myQuickSort (x:xs) = myQuickSort smaller ++ [x] ++ myQuickSort bigger
       where
       smaller = filter (<x) xs
       bigger =  filter (>=x) xs

Answer 1

也许这是一个标签问题.制表符可能看起来与一定数量的空格相同,但Haskell不会认为它们是相同的