brew/Library/Homebrew/compat/macos.rb

module MacOS
  def xcode_folder
    Xcode.folder
  end

  def xcode_prefix
    Xcode.prefix
  end

  def xcode_installed?
    Xcode.installed?
  end

  def xcode_version
    Xcode.version
  end

  def clt_installed?
    CLT.installed?
  end

  def clt_version?
    CLT.version
  end

  def x11_installed?
    X11.installed?
  end

  def x11_prefix
    X11.prefix
  end

  def leopard?
    version == 10.5
  end

  def snow_leopard?
    version >= 10.6
  end
  alias_method :snow_leopard_or_newer?, :snow_leopard?

  def lion?
    version >= 10.7
  end
  alias_method :lion_or_newer?, :lion?

  def mountain_lion?
    version >= 10.8
  end
  alias_method :mountain_lion_or_newer?, :mountain_lion?

  def macports_or_fink_installed?
    not MacOS.macports_or_fink.empty?
  end
end