# File lib/sass/script/functions.rb, line 632
    def rgb(red, green, blue)
      if calc?(red) || calc?(green) || calc?(blue)
        return unquoted_string("rgb(#{red}, #{green}, #{blue})")
      end
      assert_type red, :Number, :red
      assert_type green, :Number, :green
      assert_type blue, :Number, :blue

      color_attrs = [[red, :red], [green, :green], [blue, :blue]].map do |(c, name)|
        if c.is_unit?("%")
          c.value * 255 / 100.0
        elsif c.unitless?
          c.value
        else
          raise ArgumentError.new("Expected #{c} to be unitless or have a unit of % but got #{c}")
        end
      end

      # Don't store the string representation for function-created colors, both
      # because it's not very useful and because some functions aren't supported
      # on older browsers.
      Sass::Script::Value::Color.new(color_attrs)
    end