Haskell读入一个字符串，把它转换成数字

toint :: String->Inttoint' :: Char->Inttoint' s|s=='1' =1|s=='2' =2|s=='3' =3|s=='4' =4|s=='5' =5|s=='6' =6|s=='7' =7|s=='8' =8|s=='9' =9|s=='0' =0|otherwise = 0toint (s:xs)=if null xs then toint' s else (toint xs)*10+(toint' s)puts = doline <- getLineprint (toint (reverse line));puts

Haskell好像对缩进要求很严