Yaml example

gistfile1.hs

{-# LANGUAGE OverloadedStrings #-}
module Main where

import Data.Yaml
import System.Environment
import Control.Applicative

data Whatever = Foo { courses :: [String], required :: Int } deriving Show

instance FromJSON Whatever where
   parseJSON (Object v) = Foo <$> (v .: "courses") <*> (v .: "required") 
   parseJSON _ = fail "Fucked!"

printWhatever :: [Whatever] -> IO ()
printWhatever = mapM_ print

main = fmap head getArgs >>= decodeFile >>= \(Just x) -> printWhatever x