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{-# LANGUAGE OverloadedStrings, DeriveGeneric #-}
import qualified Data.ByteString.Lazy as BL
import Data.Csv
import Data.Text (Text)
import qualified Data.Vector as V
import GHC.Generics
data Person = Person
{ name :: !String
, salary :: !Int
}
deriving Generic
instance FromNamedRecord Person
instance ToNamedRecord Person
instance DefaultOrdered Person
persons :: [Person]
persons = [Person "John" 50000, Person "Jane" 60000]
main :: IO ()
main = do
BL.writeFile "salaries.csv" $ encodeDefaultOrderedByName persons
csvData <- BL.readFile "salaries.csv"
case decodeByName csvData of
Left err -> putStrLn err
Right (_, v) -> V.forM_ v $ \ p ->
putStrLn $ name p ++ " earns " ++ show (salary p) ++ " dollars"
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