class Sass::BaseEnvironment

def inherited_hash_reader(name)
  class_eval <<-RUBY, __FILE__, __LINE__ + 1
    def #{name}(name)
      _#{name}(name.tr('_', '-'))
    end
    def _#{name}(name)
      (@#{name}s && @#{name}s[name]) || @parent && @parent._#{name}(name)
    end
    protected :_#{name}
    def is_#{name}_global?(name)
      return !@parent if @#{name}s && @#{name}s.has_key?(name)
      @parent && @parent.is_#{name}_global?(name)
    end
  RUBY
end