class Holidays::DateCalculator::DayOfMonth

see www.irt.org/articles/js050/index.htm<br>–
=> 28
Holidays::Factory::DateCalculator.day_of_month_calculator.call(2008, 1, :last, 1)
Last Monday of January, 2008:
=> 18
Holidays::Factory::DateCalculator.day_of_month_calculator.call(2008, 12, :third, :thursday)
Third Thursday of December, 2008:
=> 7
Holidays::Factory::DateCalculator.day_of_month_calculator.call(2008, 1, :first, :monday)
First Monday of January, 2008:
===== Examples
Returns an integer.
(Saturday) or as a symbol (e.g. :monday).
[wday] Day of the week as an integer from 0 (Sunday) to 6
:fourth, :fifth or :last.
[week] One of :first, :second, :third,
[month] Integer from 1-12.
[year] Integer.
==== Parameters
week.
Calculate day of the month based on the week number and the day of the

def call(year, month, week, wday) 

def call(year, month, week, wday)
  raise ArgumentError, "Week parameter must be one of Holidays::WEEKS (provided #{week})." unless weeks.include?(week) or weeks.has_value?(week)
  unless wday.kind_of?(Numeric) and wday.between?(0,6) or day_symbols.index(wday)
    raise ArgumentError, "Wday parameter must be an integer between 0 and 6 or one of Holidays::DAY_SYMBOLS."
  end
  week = weeks[week] if week.kind_of?(Symbol)
  wday = day_symbols.index(wday) if wday.kind_of?(Symbol)
  # :first, :second, :third, :fourth or :fifth
  if week > 0
    return ((week - 1) * 7) + 1 + ((wday - Date.civil(year, month,(week-1)*7 + 1).wday) % 7)
  end
  days = month_lengths[month-1]
  days = 29 if month == 2 and Date.leap?(year)
  return days - ((Date.civil(year, month, days).wday - wday + 7) % 7) - (7 * (week.abs - 1))
end

def day_symbols 

def day_symbols
  Holidays::DAY_SYMBOLS
end

def month_lengths 

def month_lengths
  Holidays::MONTH_LENGTHS
end

def weeks 

def weeks
  Holidays::WEEKS
end