    # File lib/compass/sass_extensions/functions/gradient_support.rb, line 358
        def grad_position(color_list, index, default, radial = Sass::Script::Bool.new(false))
          assert_type color_list, :List
          stop = color_list.value[index.value - 1].stop
          if stop && radial.to_bool
            orig_stop = stop
            if stop.unitless?
              if stop.value <= 1
                # A unitless number is assumed to be a percentage when it's between 0 and 1
                stop = stop.times(Sass::Script::Number.new(100, ["%"]))
              else
                # Otherwise, a unitless number is assumed to be in pixels
                stop = stop.times(Sass::Script::Number.new(1, ["px"]))
              end
            end
            if stop.numerator_units == ["%"] && color_list.value.last.stop && color_list.value.last.stop.numerator_units == ["px"]
              stop = stop.times(color_list.value.last.stop).div(Sass::Script::Number.new(100, ["%"]))
            end
            Compass::Logger.new.record(:warning, "Webkit only supports pixels for the start and end stops for radial gradients. Got: #{orig_stop}") if stop.numerator_units != ["px"]
            stop.div(Sass::Script::Number.new(1, stop.numerator_units, stop.denominator_units))
          elsif stop
            stop
          else
            default
          end
        end