Haskell Formatting Issue

Question

main :: IO ()
main = do 
    contents <- readFile "text.txt"
    let database = (read contents :: [Film])
    putStr "Please enter your username: "
    userName <- getLine
    menu database        
    where menu newDb = do putStrLn "\nPlease select an option:"
                          putStrLn "1: Display all films currently in the database"
                          putStrLn "2: Add a new film to the database"
                          putStrLn "3: Search for films by director"
                          putStrLn "5: Exit"
                          putStr "\nSelected option: "
                          option <- getLine
                          case option of 
                                        "1" -> putStrLn(formatDatabase newDb)
                                        "2" -> do putStr "Name of film: "
                                               title <- getLine
                                               putStr "Name of director: "
                                               director <- getLine
                                               putStr "Year of release: "
                                               year <- getLine
                                               putStrLn(formatDatabase $ addFilm title director (read year) [] newDb)
                                        "3" -> do putStr "Name of director: "
                                               director <- getLine
                                               putStrLn $ formattedByDirector director
                          menu newDb

Returns error:

Parse error in pattern: putStr

On the line: "2" -> do putStr "Name of film: "

Answer 1

Please do not indent your code in the manner found in many textbooks. It looks nice on paper, but is terrible for actually working with.

Here's a much more sane style guide: https://github.com/tibbe/haskell-style-guide

Answer 2

You must indent the lines in the do block all to the level of the first token after the do. The same applies to the case 3.

case option of 
  "1" -> putStrLn(formatDatabase newDb)
  "2" -> do putStr "Name of film: "
            title <- getLine
            putStr "Name of director: "
            director <- getLine
            putStr "Year of release: "
            year <- getLine
            putStrLn(formatDatabase $ addFilm title director (read year) [] newDb)
  "3" -> do putStr "Name of director: "
            director <- getLine
            putStrLn $ formattedByDirector director