atondwal

{-# LANGUAGE OverloadedStrings #-}
{-# LANGUAGE FlexibleInstances #-}
{-# LANGUAGE MonadComprehensions #-}
{-# LANGUAGE LambdaCase #-}

import Control.Applicative
import Control.Monad.State.Strict
import Data.Function (on)
import Data.Foldable (foldrM)
import Data.Attoparsec