#!/usr/bin/env runhaskell

-- import Text.Pandoc.Pretty
-- import Text.Pandoc.JSON
import Text.Pandoc.Pretty
import Text.Pandoc.JSON
import qualified Text.Pandoc.Walk as W
import System.IO
import qualified Data.Aeson as A
import qualified Data.ByteString.Lazy as BL

extract_title :: Pandoc -> String
extract_title d@(Pandoc m _) = do
  title <- render Nothing $ cat $ map pretty (docTitle m)
  return title
    where pretty :: Inline -> Doc
          pretty (Str s) = text s
          pretty Space = space
          pretty _ = empty

main :: IO ()
main = do
  input <- BL.getContents
  let title = (W.query extract_title :: Pandoc -> String) . either error id . A.eitherDecode' $ input
  putStrLn title