gistfile1.txt

require "execjs"

class ExecJS::ExternalRuntime
  def exec_runtime(filename)
    r, w = IO.pipe
    pid = Kernel.spawn("#{binary} #{filename}", :out => w, :err=>[:child, :out])
    puts "#{binary} PID: #{pid}"
    w.close
    Process.wait(pid)

    output = r.read
    r.close

    puts "output: #{output.inspect}"
    puts "last command: #{$?.inspect}"
    if $?.success?
      output
    else
      raise exec_runtime_error(output)
    end
  end
end

ExecJS.compile(File.read('/tmp/uglify.js'))