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

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



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# File 'lib/weekday.rb', line 38

def self.method_missing(m, *args)
  # first_thursdays(year)
  count_s,weekday = m.to_s.split('_')
  if DAYNAMESS.include?(weekday) and args.size == 1
    unless COUNTWORDS.include?(count_s)
      raise NoMethodError, "undefined method `#{m}'"
    end
    count = COUNTWORDS.index(count_s)+1
    wnum = DAYNAMESS.index(weekday)
    year = args[0]
    result = []
    1.upto(12) do |month|
	result << self.send(count_s+"_"+DAYNAMES[wnum],year,month) 
    end
    return result
  end
  # end first_thursdays
  # 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

.nth(count, weekday, year, month) ⇒ Object

just another notation if you have to calculate the weekdays programmatically

  • count: 1..5 first, second; -1 last

  • weekday: 0: sunday, 1: monday, … 6: saturday

  • year

  • month

Raises:

  • (ArgumentError) 


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# File 'lib/weekday.rb', line 142

def Weekday.nth(count, weekday, year, month)
  raise ArgumentError unless count >= 1 and count <=5 or count == -1
  if count == -1
    s = COUNTWORDS.last + '_' + DAYNAMES[weekday]
  else
    s = COUNTWORDS[count-1] + '_' + DAYNAMES[weekday]
  end
  self.send(s,year,month)
end