def colorize_null(params = {}, &block)
      component[:null_colorizer] = (params[:using] or block)
      component[:null_colorizer] ||= proc do |value|
        params[:with]
      end
    end
def colorize_null(params = {}, &block)
      component[:null_colorizer] = (params[:using] or block)
      component[:null_colorizer] ||= proc do |value|
        params[:with]
      end
    end
Defines a colorizer to null values.

 === Args

 +params+::
   A hash with params in case a block is not given:
     - :using defines the component to use
     - :with defines the format to use