# File lib/multiruby.rb, line 153
  def self.matching_versions url, matching=nil
    file = URI.parse(url).read

    map = {
      "preview" => "beta",
      "rc"      => "beta2",
      "p"       => "release",
      "tar"     => "aargh",
      "gz"      => "aargh",
    }

    versions = file.scan(/href="(ruby.*tar.gz)"/).flatten.sort_by { |s|
      s.scan(/\d+|[a-z]+/).map { |a| Integer(a) rescue map[a] || a }
    }

    versions = versions.grep(/#{Regexp.escape(matching)}/) if matching

    versions
  end