csv.hs

{-# LANGUAGE ScopedTypeVariables #-}

import qualified Data.ByteString.Lazy as BL
import Data.Csv
import qualified Data.Vector as V
import Control.Arrow
import Data.List
import Data.Function


combine :: [(String,Int)] -> [(String, Int)]
combine = map ((fst . head)  &&& (sum . map snd)) . groupBy ((==) `on` fst) . sort 

main :: IO ()
main = do
    csvData <- BL.readFile "/home/atondwal/src/lh-prover/popl18/z3pbe.csv"
    case decode NoHeader csvData of
        Left err -> putStrLn err
        Right v -> BL.putStr $ encode $ combine $ V.toList v