class Eigen < Formula
  desc "C++ template library for linear algebra"
  homepage "https://eigen.tuxfamily.org/"
  url "https://bitbucket.org/eigen/eigen/get/3.3.5.tar.bz2"
  sha256 "7352bff3ea299e4c7d7fbe31c504f8eb9149d7e685dec5a12fbaa26379f603e2"
  head "https://bitbucket.org/eigen/eigen", :using => :hg

  bottle do
    cellar :any_skip_relocation
    sha256 "2d341f7f61d359f16052ad4943d92f44be362ac978c435797785739e1ce0bdf8" => :mojave
    sha256 "058b1692b9ccb2e54d062cd1ef947ee89984cc5f818202100284218d6e3a3b32" => :high_sierra
    sha256 "058b1692b9ccb2e54d062cd1ef947ee89984cc5f818202100284218d6e3a3b32" => :sierra
    sha256 "058b1692b9ccb2e54d062cd1ef947ee89984cc5f818202100284218d6e3a3b32" => :el_capitan
  end

  depends_on "cmake" => :build

  def install
    mkdir "eigen-build" do
      args = std_cmake_args
      args << "-Dpkg_config_libdir=#{lib}" << ".."
      system "cmake", *args
      system "make", "install"
    end
    (share/"cmake/Modules").install "cmake/FindEigen3.cmake"
  end

  test do
    (testpath/"test.cpp").write <<~EOS
      #include <iostream>
      #include <Eigen/Dense>
      using Eigen::MatrixXd;
      int main()
      {
        MatrixXd m(2,2);
        m(0,0) = 3;
        m(1,0) = 2.5;
        m(0,1) = -1;
        m(1,1) = m(1,0) + m(0,1);
        std::cout << m << std::endl;
      }
    EOS
    system ENV.cxx, "test.cpp", "-I#{include}/eigen3", "-o", "test"
    assert_equal %w[3 -1 2.5 1.5], shell_output("./test").split
  end
end