1.hs

replace' :: Eq b => b -> b -> [b] -> [b]
replace' a b = map (\x -> if (a == x) then b else x)

main = do
  f <- readFile "1input"
  let l = lines $ replace' '+' ' ' f
  map (read::String->Int) l
  putStrLn "hi"

1.hs:13:3: error:
    • Couldn't match type ‘[]’ with ‘IO’
      Expected type: IO Int
        Actual type: [Int]
    • In a stmt of a 'do' block: map (read :: String -> Int) l
      In the expression:
        do f <- readFile "1input"
           let l = lines $ replace' '+' ' ' f
           map (read :: String -> Int) l
           putStrLn "hi"
      In an equation for ‘main’:
          main
            = do f <- readFile "1input"
                 let l = ...
                 map (read :: String -> Int) l
                 ....
   |
13 |   map (read::String->Int) l