Named Fields

gistfile1.hs

module Main where

data Option =
  Option
  { option1 :: String
  , option2 :: Maybe String
  , option3 :: Maybe String
  } deriving (Show)


opt = Option
      { option1 = "Option1"
      , option2 = Nothing
      , option3 = Just "Option3"
      }

getOption3 :: Option -> String
getOption3 (Option _ _ (Nothing)) = ""
getOption3 (Option _ _ (Just x)) = x

getOption2 :: Option -> String
getOption2 (Option {option2 = Nothing}) = ""
getOption2 (Option {option2 = Just x}) = x

main = putStrLn $ show $ getOption2 opt