murb/workbook

# frozen_string_literal: true

module Workbook
  # Used in cases col or rowspans are used
  class NilValue
    # initialize this special nilvalue with a reason
    # @param [String] reason (currently only :covered, in case this cell is coverd because an adjecant cell spans over it)
    def initialize reason
      self.reason = reason
    end

    # returns the value of itself (nil)
    # @return [NilClass] nil
    def value
      nil
    end

    def <=> other
      value <=> other
    end

    attr_reader :reason

    # set the reason why this value is nil
    def reason= reason
      if reason == :covered
        @reason = reason
      else
        raise "invalid reason given"
      end
    end
  end
end