#!/usr/bin/env nix-script
#!>haskell

{- Calculate words frequency. Use in a pipe. -}

import Data.List
import Data.Ord  (comparing)
import Data.Map  (toList, fromListWith)

freqs = sort' . toList . fromListWith (+) . map t
  where
    t x = (x, 1)
    sort' = reverse . sortBy (comparing snd)

pretty = intercalate "\n" . map line
  where line (x, y) = x ++ ": " ++ show y

best = filter ((>50) . snd)

main = interact (pretty . freqs . words)