module CALCULATION_INTERVAL

A method for calculating the number of sitting days in both Houses during an interval.

We pass the start and end dates of the interval.

   def calculate_sitting_days_in_interval( start_date, end_date )

We set the date to start counting from to the start date.

     date = @start_date

Whilst the date is not later than the end date ...

     while date <= @end_date

If the date is a Commons sitting day ...

       if date.is_commons_actual_sitting_day?

... we increment the Commons sitting day count.

         @commons_sitting_day_count += 1

       end

If the date is a Lords sitting day ...

       if date.is_lords_actual_sitting_day?

... we increment the Lords sitting day count.

         @lords_sitting_day_count += 1

       end

We continue to the next day.

       date = date.next_day

     end

   end

 end