code: def eval_stdin():
      'evaluate expressions read from stdin'
      cmd = ['plash', 'eval']
      p = subprocess.Popen(cmd, stdin=sys.stdin, stdout=sys.stdout)
      exit = p.wait()
      if exit:
          raise subprocess.CalledProcessError(exit, cmdf eval_stdin():
      'evaluate expressions read from stdin'
      cmd = ['plash', 'eval']
      p = subprocess.Popen(cmd, stdin=sys.stdin, stdout=sys.stdout)
      exit = p.wait()
      if exit:
          raise subprocess.CalledProcessError(exit, cmd)
docs: evaluate expressions read from stdin