# File lib/runt/daterange.rb, line 43
    def gap(obj)

      return EMPTY if self.overlap? obj

      lower=nil
      higher=nil

      if((self<=>obj)<0)
        lower=self
        higher=obj
      else
        lower=obj
        higher=self
      end

      return DateRange.new((lower.end_expr+1),(higher.start_expr-1))
    end