yuppie is working on a xonsh formula for Homebrew

xonsh.rb

class Xonsh < Formula
  homepage "http://xonsh.org"
  url "https://github.com/scopatz/xonsh/archive/0.1.0.tar.gz"
  sha256 "c77dc7176bd9035e90a448d5a208d4d176535545335678443769602f59f170b6"

  depends_on :python3

  resource "ply" do
    url "https://pypi.python.org/packages/source/p/ply/ply-3.6.tar.gz"
    sha256 "61367b9eb2f4b819f69ea116750305270f1df8859992c9e356d6a851f25a4b47"
  end

  def install
    version = Language::Python.major_minor_version "python3"
    ENV["PYTHONPATH"] = lib/"python#{version}/site-packages"
    ENV.prepend_create_path "PYTHONPATH", libexec/"lib/python#{version}/site-packages"

    resource("ply").stage do
      system "python3", *Language::Python.setup_install_args(libexec)
    end

    system "python3", *Language::Python.setup_install_args(libexec)
    bin.env_script_all_files(prefix, :PYTHONPATH => ENV["PYTHONPATH"])
  end

  test do
    system "false"
  end
end