Rosetta Code

Discordian date

Convert Gregorian dates into the Discordian calendar.

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Sourcerosettacode/popular/discordian_date.vibe
def leap_year?(year: int) -> bool
  if year % 400 == 0
    true
  elsif year % 100 == 0
    false
  else
    year % 4 == 0
  end
end

def day_of_year(year: int, month: int, day: int) -> int
  lengths = [31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31]
  total = 0
  index = 0

  while index < month - 1
    total = total + lengths.fetch(index)
    index = index + 1
  end

  if month > 2 && leap_year?(year)
    total = total + 1
  end

  total + day
end

def discordian_date(year: int, month: int, day: int) -> hash<string, int | string>
  if leap_year?(year) && month == 2 && day == 29
    return {
      year: year + 1166,
      holiday: "St. Tib's Day"
    }
  end

  day_index = day_of_year(year, month, day) - 1
  if leap_year?(year) && day_index > 59
    day_index = day_index - 1
  end

  seasons = ["Chaos", "Discord", "Confusion", "Bureaucracy", "The Aftermath"]
  weekdays = ["Sweetmorn", "Boomtime", "Pungenday", "Prickle-Prickle", "Setting Orange"]

  {
    year: year + 1166,
    weekday: weekdays.fetch(day_index % 5),
    day: (day_index % 73) + 1,
    season: seasons.fetch(day_index // 73)
  }
end

def run -> array<hash<string, int | string>>
  [
    discordian_date(2024, 2, 29),
    discordian_date(2026, 3, 8),
    discordian_date(2025, 9, 19)
  ]
end

Output

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