class Sass::BaseEnvironment

def inherited_hash_writer(name)
  class_eval <<-RUBY, __FILE__, __LINE__ + 1
    def set_#{name}(name, value)
      name = name.tr('_', '-')
      @#{name}s[name] = value unless try_set_#{name}(name, value)
    end
    def try_set_#{name}(name, value)
      @#{name}s ||= {}
      if @#{name}s.include?(name)
        @#{name}s[name] = value
        true
      elsif @parent && !@parent.global?
        @parent.try_set_#{name}(name, value)
      else
        false
      end
    end
    protected :try_set_#{name}
    def set_local_#{name}(name, value)
      @#{name}s ||= {}
      @#{name}s[name.tr('_', '-')] = value
    end
    def set_global_#{name}(name, value)
      global_env.set_#{name}(name, value)
    end
  RUBY
end