Generate help text if no default mode was specified about cmdargs HOT 2 CLOSED

import System.Console.CmdArgs (cmdArgsRun)
import System.Console.CmdArgs.Explicit(helpText, HelpFormat(..))

main :: IO()
main = do
  args <- getArgs
  if null args then exitWithHelp
  else parse =<< cmdArgsRun mode

exitWithHelp :: IO a
exitWithHelp = do
  putStr $ show $ helpText [] HelpFormatAll mode
  exitSuccess