bsp2csv in Haskell

bcp2csv.hs

import System.Environment
import Data.List.Split
import Data.List.Utils
import Data.List

-- usage: $ ./bcp2csv input.txt output.txt
main :: IO ()
main = do
  args <- getArgs
  input <- readFile $ head args
  let outputFilename = args !! 1
  writeFile outputFilename . unlines . map joinWithCommas $ parseAndEscapeBCP input

-- runs the escaping code on the nested list data structure generated by parseBCP.
parseAndEscapeBCP :: String -> [[String]]
parseAndEscapeBCP input = map (map (quoteIfNecessary . escapeQuotes)) $ parseBCP input

-- parses BCP file into nested Lists. top level is lines, next level is fields.
parseBCP :: String -> [[String]]
parseBCP input = map splitFields $ splitLines input

splitLines :: String -> [String]
splitLines input = splitOn "&$&" input

splitFields :: String -> [String]
splitFields input = splitOn "#&#" input

escapeQuotes :: String -> String
escapeQuotes input
    | '"' `elem` input = replace "\"" "\"\"\"" input
    | otherwise = input

quoteIfNecessary :: String -> String
quoteIfNecessary input
    | '\n' `elem` input || ',' `elem` input || '"' `elem` input = wrapInQuotes input
    | otherwise = input

wrapInQuotes :: String -> String
wrapInQuotes input = "\"" ++ input ++ "\"" 

joinWithCommas :: [String] -> String
joinWithCommas list = intercalate "," list