Class: WhenEaster

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

Class Method Summary collapse

Class Method Details

.find(year = nil) ⇒ Object

WhenEaster.find

> In the year 2011, the Roman Easter is on 24 April. n In the year 2011, the Greek Easter is on 24 April.



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# File 'lib/when_easter.rb', line 4

def self.find(year = nil)
  roman_date = self.roman_easter(year)
  greek_date = self.greek_easter(year)
  return "In the year #{roman_date.year}, the Roman Easter is on #{roman_date.strftime("%d %B")}. \nIn the year #{greek_date.year}, the Roman Easter is on #{greek_date.strftime("%d %B")}."
end

.find_greek(year) ⇒ Object

WhenEaster.find_greek

> In the year 2011, the Greek Easter is on 24 April.



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# File 'lib/when_easter.rb', line 19

def self.find_greek(year)
  date = self.greek_easter(year)
  return "In the year #{date.year}, the Greek Easter is on #{date.strftime("%d %B")}."
end

.find_roman(year = nil) ⇒ Object

WhenEaster.find_roman

> In the year 2011, the Roman Easter is on 24 April.



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# File 'lib/when_easter.rb', line 12

def self.find_roman(year = nil)
  date = self.roman_easter(year)
  return "In the year #{date.year}, the Roman Easter is on #{date.strftime("%d %B")}."
end

.greek_easter(year = nil) ⇒ Object

WhenEaster.greek_easter

> Sun Apr 24 00:00:00 +0200 2011



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# File 'lib/when_easter.rb', line 57

def self.greek_easter(year = nil)
  year = Time.now.year if year.nil?
  year = year.to_i if year.is_a?(String)
  a = year % 19
  b = year % 4
  c = year % 7
  d = (19 * a + 16) % 30
  e = (2 * b + 4 * c + 6 * d) % 7;
  easter = 3 + d + e;
  if easter <= 30
    Time.local(year, 4, easter)
  else
    Time.local(year, 5, (easter - 30))
  end
end

.roman_easter(year = nil) ⇒ Object

WhenEaster.roman_easter

> Sun Apr 24 00:00:00 +0200 2011



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# File 'lib/when_easter.rb', line 25

def self.roman_easter(year = nil)
  year = Time.now.year if year.nil?
  year = year.to_i if year.is_a?(String)
  g = year % 19 +1
  s = (year -1600) / 100 - (year-1600) / 400
  l = (((year - 1400) / 100) * 8) / 25
  
  p_2 = (3-11*g +s -l) % 30
  if p_2 == 29 || (p_2 == 28 && g > 11) 
    p = p_2 -1
  else
    p= p_2
  end
  
  d= (year + year / 4 - year / 100 + year / 400) % 7
  d_2 = (8-d) % 7
  
  p_3 = (80 + p) % 7
  x_2 = d_2 - p_3
  
  x = (x_2 -1) % 7 +1
  e = p+x
  
  if e < 11 
    Time.local(year,3,e+21)
  else
    Time.local(year,4,e-10)
  end
end