jsaddle1.hs

#!/usr/bin/env nix-shell
#! nix-shell -p "haskell.packages.ghc822.ghcWithPackages (p: with p; with haskell.lib; [(doJailbreak (dontCheck jsaddle-warp))])"
#! nix-shell -i "runghc"

{-# language OverloadedStrings #-}

import            Control.Monad.IO.Class
import            Language.Javascript.JSaddle.Warp
import            Language.Javascript.JSaddle
import            Language.Javascript.JSaddle.Debug
import            Control.Concurrent
import            Control.Monad
import            Data.Text
import            Control.Concurrent.MVar

main = run 3197 $ do
  result <- liftIO newEmptyMVar
  deRefVal $ call (eval "(function(f) {f('Hello');})") global [fun $ \ _ _ [arg1] -> do
    valToText arg1 >>= (liftIO . putMVar result)
    ]
  liftIO $ takeMVar result