Pony example of just piping stdin to stdout.

pipe.pony

actor Main
  let env: Env
  new create(env': Env) =>
    env = env'
    env.input(notify())
  
  be print(data: ByteSeq val) =>
    env.out.print(data)
  
  fun tag notify(): StdinNotify iso^ =>
    object iso is StdinNotify
      let parent: Main = this
      fun ref apply(data: Array[U8] iso) =>
        parent.print(consume data)
    end