Class: Weekday

Inherits:
Object
  • Object
show all
Defined in:
lib/weekday.rb

Constant Summary collapse

COUNTWORDS = 
%w(first second third fourth fifth last)
DAYNAMES = 
%w(sunday monday tuesday wednesday thursday friday saturday)
DAYNAMESS = 
%w(sundays mondays tuesdays wednesdays thursdays fridays saturdays)
PREV = 
%w(nil nil) + COUNTWORDS
ILLEGAL_ARGUMENTS = 
"illegal month or year number"
DAYS_PER_WEEK = 
7

Class Method Summary collapse

Class Method Details

.method_missing(m, *args) ⇒ Object

Weekday.method_missing implements the methods like

  • Weekday.second_tuesday(2010,12) or

  • Weekday.last_monday(2010,11)

The return value is a date object or nil if there is no Nth Xday in this month

  • Weekday.mondays(2011,2) returns an array of all mondays in this month

  • Weekday.first_monday(2011) returns the very first monday in this year

  • Weekday.last_monday(2011) returns the very last monday in this year

  • Weekday.mondays(2011) returns all mondays in this year as an array of Date objects



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# File 'lib/weekday.rb', line 36

def self.method_missing(m, *args)
  # self.mondays .. self.sundays
  if DAYNAMESS.include?(m.to_s)
    wnum = DAYNAMESS.index(m.to_s)
    raise ArgumentError, ILLEGAL_ARGUMENTS unless args[0] or args[1]
    # mondays .. sundays without a month => calculate complete year
    unless args[1]
	result = []
	1.upto(12) do |mm|
 result = (result + self.send(m,args[0],mm)).flatten
	end
	return result
    end
    begin
      d = Date.new(args[0],args[1])
    rescue ArgumentError
      raise ArgumentError, ILLEGAL_ARGUMENTS
    end
    result = []
    while d.month == args[1] do
      if d.wday == wnum
        result << d
        loop do
          d += DAYS_PER_WEEK
          break if not d.month == args[1]
          result << d
        end
      end
      d += 1
    end
    return result
  end
  count,weekday = m.to_s.split('_')
  unless COUNTWORDS.include?(count)
    raise NoMethodError, "undefined method `#{m}'"
  end
  count = COUNTWORDS.index(count)+1
  wnum = DAYNAMES.index(weekday)
  unless wnum
    raise NoMethodError, "undefined method `#{m}'"
  end
  # self.last_monday .. self.last_sunday
  if count == COUNTWORDS.index(COUNTWORDS[-1])+1
    args[1] = 12 if args[1] == nil # december if no month was given at
                                   # last_xxx(year)
    d = Date.new(args[0],args[1],-1)
    while not d.wday == wnum do
      d -= 1
    end
    return d
  end
  case count
  when 1
    # at least a year must be given
    raise ArgumentError, ILLEGAL_ARGUMENTS unless args[0] or args[1]
    args[1] = 1 if args[1] == nil # january if no month was given at
                                  # first_xxx(year)
    begin
      d = Date.new(args[0],args[1],1)
    rescue ArgumentError
      raise ArgumentError, ILLEGAL_ARGUMENTS
    end
    while not d.wday == wnum do
      d += 1
    end
    return d
  when 2..5
    m_name = (PREV[count] + '_' + weekday).to_sym
    prev = self.send((PREV[count] + '_' + weekday), args[0], args[1])
    result = if prev
      prev + DAYS_PER_WEEK
    else
      nil
    end
    unless result and result.month == args[1]
      result = nil
    end
    return result
  else
    raise NoMethodError, "undefined method `#{m}'"
  end
end