Look Ma, no callbacks! (Using PureScript's Aff Monad with NodeJS.)

Main.purs

module Main where

import Prelude
import Control.Monad.Aff (attempt, forkAff, launchAff)
import Control.Monad.Eff (Eff)
import Control.Monad.Eff.Class (liftEff)
import Control.Monad.Eff.Console (CONSOLE, log)
import Control.Monad.Eff.Exception (EXCEPTION)
import Data.Either (Either(..))
import Node.Encoding (Encoding(..))
import Node.FS (FS)
import Node.FS.Aff (readTextFile)

main :: forall e. Eff ( exception :: EXCEPTION
                      , fs        :: FS 
                      , console   :: CONSOLE| e) Unit
main = void $ launchAff do
  _ <- forkAff $ do
          greet <- attempt $ readTextFile UTF8 "./greet.txt"
          case greet of
            Left err  -> liftEff $ log "Error, yo!"
            Right res -> liftEff $ log res
  liftEff $ log "The last shall be first."