Модуль:Календарь

Материал из свободной русской энциклопедии «Традиция»
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Модуль для календарных расчётов.

Функции:

Пасхалия 
Функция для расчёта Пасхи и привязанных к ней праздников
десятилетие 
Функция для расчёта десятилетия, которому принадлежит год
пасхалия 
Функция для расчёта Пасхи и привязанных к ней праздников

local m = {}
 
local CalendarData = {
    defaultMethod = 2,        -- default method of Easter date calculation when Easter type is not given
    defaultFormat = "d.m.Y",  -- default date output format
    noFormat      = "none",   -- prevent from final date formatting
    defaultOffset = 0,        -- the Easter date
    minimumOffset = -63,      -- Septuagesima
    maximumOffset = 68,       -- Feast of the Sacred Heart

    decadeSuffix  = "-е",     -- Напр., 1990-е.
    BC            = "до н. э.",
 
    -- API:
    -- Easter:
    apiEaster            = "пасхалия",  -- public function name
    argYear              = 1,           -- index or name of the argument with year
    argEasterMethod      = "пасхалия",  -- index or name of the argument with calculation method
    argEasterOffset      = "день",      -- index or name of the argument with offset in days relative to the calculated Easter Sunday
    argEasterFormat      = "формат",    -- index or name of the argument with date output format (#time style)
    -- Decades:
    apiDecade            = "десятилетие",
    argYearOffset        = 2,
 
    -- errors
    errorMissingYear       = "Не указан год",
    errorInvalidYear       = "Аргумент «год» неверен: '%s'",
    errorNo0thYear         = "Нулевого года не бывает",
    errorInvalidOffset     = "Аргумент «дни» ошибочен: '%s'",
    errorInvalidMethod     = "Аргумент «пасхалия» ошибочен: '%s'",
    errorYearOutOfRange    = "Пасха рассчитывается только с 326 по 4099 годы; указан год %d",
    errorIncorrectMethod   = "Западная и православная пасхалии отделяются от юлианской только с 1583; указан год %d",
    errorUnknownMethod     = "Неизвестный метод: %d",
    errorInvalidYearOffset = "Аргумент «сдвиг» неверен: '%s'",
 
    methods = {
        ["юлианская"]     = 1,
        ["восточная"]     = 2,
        ["православная"]  = 2, -- alias for Eastern
        ["западная"]      = 3,
        ["римская"]       = 3, -- alias for Roman
    },
 
    relativeDates = {
        ["Семидесятница"]            = -63,
        ["Sexagesima"]               = -56,
        ["Fat Thursday"]             = -52,
        ["Прощёное воскресенье"]     = -49,
        ["Чистый понедельник"]       = -48,
        ["Пепельная среда"]          = -46,
        ["Вербное воскресенье"]      =  -7,
        ["Чистый четверг"]           =  -3,
        ["Великий четверг"]          =  -3,
        ["Страстная пятница"]        =  -2,
        ["Великая суббота"]          =  -1, 
        ["Пасха"]                    =   0,
        ["Пасхальный понедельник"]   =   1,
        ["Вознесение"]               =  39,
        ["Отдание Пасхи"]            =  39,
        ["Пятидесятница"]            =  49,
        ["Corpus Christi"]           =  60,
    },
}
 
local function formatCalendarError (message, ...)
    if select('#', ... ) > 0 then
        message = string.format(message, ...)
    end
    return "<span class=\"error\">" .. message .. "</span>"
end
 
local function loadYear(year)
    if not year then
        return false, formatCalendarError (CalendarData.errorMissingYear)
    end
    local result = tonumber(year)
    if not result or math.floor(result) ~= result then
        return false, formatCalendarError (CalendarData.errorInvalidYear, year)
    end
    if result == 0 then
        return false, formatCalendarError (CalendarData.errorNo0thYear, year)
    end

    return true, result
end
 
local function loadEasterMethod(method, year)
    local result = CalendarData.defaultMethod
    if method then
        result = CalendarData.methods[method]
        if not result then
            return false, formatCalendarError (CalendarData.errorInvalidMethod, method)
        end
    end
 
    if year < 1583 then
        result = 1
    end
 
    return true, result
end
 
local function loadEasterOffset(day)
    if not day then
        return true, ""
    end
 
    local data = CalendarData.relativeDates
    local offset = tonumber(day)
    if not offset then
        offset = data[day]
    end
    if not offset or offset ~= math.floor(offset) or offset < CalendarData.minimumOffset or offset > CalendarData.maximumOffset then
        return false, formatCalendarError (CalendarData.errorInvalidOffset, day)
    end

    if offset < -1 then
        return true, string.format(" %d days", offset)
    elseif offset == -1 then
        return true, " -1 day"
    elseif offset == 0 then
        return true, ""
    elseif offset == 1 then
        return true, " +1 day"
    else -- if offset > 1 then
        return true, string.format(" +%d days", offset)
    end
end
 
local function loadEasterFormat(fmt)
    if fmt == CalendarData.noFormat then
        return true, nil
    elseif not fmt then
        return true, CalendarData.defaultFormat
    else
        return true, fmt
    end
end
 
--[[
 PURPOSE:     This function returns Easter Sunday day and month
              for a specified year and method.
 
 INPUTS:      Year   - Any year between 326 and 4099.
              Method - 1 = the original calculation based on the
                           Julian calendar
                       2 = the original calculation, with the
                           Julian date converted to the
                           equivalent Gregorian calendar
                       3 = the revised calculation based on the
                           Gregorian calendar
 
 OUTPUTS:     None.
 
 RETURNS:     0, error message - Error; invalid arguments
              month, day       - month and day of the Sunday
 
 NOTES:
              The code is translated from DN OSP 6.4.0 sources.
              The roots of the code might be found in
              http://www.gmarts.org/index.php?go=415
 
 ORIGINAL NOTES:
 
              This algorithm is an arithmetic interpretation
              of the 3 step Easter Dating Method developed
              by Ron Mallen 1985, as a vast improvement on
              the method described in the Common Prayer Book
 
              Published Australian Almanac 1988
              Refer to this publication, or the Canberra Library
              for a clear understanding of the method used
 
              Because this algorithm is a direct translation of
              the official tables, it can be easily proved to be
              100% correct
 
              It's free! Please do not modify code or comments!
]]
local function calculateEasterDate(year, method)
    if year < 326 or year > 4099 then
        -- Easter dates are valid for years between 326 and 4099
        return 0, formatCalendarError  (CalendarData.errorYearOutOfRange, year)
    end
    if year < 1583 and method ~= 1 then
        -- Western or Orthodox Easter is valid since 1583
        return 0, formatCalendarError  (CalendarData.errorIncorrectMethod, year)
    end
 
    -- intermediate result
    local firstDig = math.floor(year / 100)
    local remain19 = year % 19
    local temp = 0
    -- table A to E results
    local tA = 0
    local tB = 0
    local tC = 0
    local tD = 0
    local tE = 0
     -- Easter Sunday day
    local d = 0
 
    if method == 1 or method == 2 then
        -- calculate PFM date
        tA   = ((225 - 11 * remain19) % 30) + 21
        -- find the next Sunday
        tB   = (tA - 19) % 7
        tC   = (40 - firstDig) % 7
        temp = year % 100
        tD   = (temp + math.floor(temp / 4)) % 7
        tE   = ((20 - tB - tC - tD) % 7) + 1
        d    = tA + tE
        if method == 2 then
            -- convert Julian to Gregorian date
            -- 10 days were skipped in the Gregorian calendar from 5-14 Oct 1582
            temp = 10
            -- only 1 in every 4 century years are leap years in the Gregorian
            -- calendar (every century is a leap year in the Julian calendar)
            if year > 1600 then
                temp = temp + firstDig - 16 - math.floor((firstDig - 16) / 4)
            end
            d = d + temp
        end
    elseif method == 3 then
        -- calculate PFM date
        temp = math.floor((firstDig - 15) / 2)  + 202 - 11 * remain19
        if firstDig > 26 then
            temp = temp - 1
        end
        if firstDig > 38 then
            temp = temp - 1
        end
        if firstDig == 21 or firstDig == 24 or firstDig == 25 or firstDig == 33 or firstDig == 36 or firstDig == 37 then
            temp = temp - 1
        end
        temp = temp % 30
        tA   = temp + 21
        if temp == 29 then
            tA = tA - 1
        end
        if temp == 28 and remain19 > 10 then
            tA = tA - 1
        end
        -- find the next Sunday
        tB   = (tA - 19) % 7
        tC   = (40 - firstDig) % 4
        if tC == 3 then
            tC = tC + 1
        end
        if tC > 1 then
            tC = tC + 1
        end
        temp = year % 100
        tD   = (temp + math.floor(temp / 4)) % 7
        tE   = ((20 - tB - tC - tD) % 7) + 1
        d    = tA + tE
    else
        -- Unknown method
        return 0, formatEeasteError(CalendarData.errorUnknownMethod, method)
    end
    if d > 61 then
        -- when the oryginal calculation os converted to the Gregorian
        -- calendar, Easter Sunday can occur in May
        return 5, d - 61
    elseif d > 31 then
        return 4, d - 31
    else
        return 3, d
    end
end
 
local function Easter (args)
    local ok
    local year
    ok, year = loadYear (args[CalendarData.argYear])
    if not ok then
        return year
    end
 
    local method
    ok, method = loadEasterMethod (args[CalendarData.argEasterMethod], year)
    if not ok then
        return method
    end
 
    local offset
    ok, offset = loadEasterOffset (args[CalendarData.argEasterOffset])
    if not ok then
        return offset
    end
 
    local format
    ok, format = loadEasterFormat (args[CalendarData.argEasterFormat])
    if not ok then
        return format
    end
 
    local month, day = calculateEasterDate (year, method)
    if month == 0 then
        return day
    end
 
    local result = string.format("%04d-%02d-%02d%s", year, month, day, offset)
    if format then
        result = mw.language.getContentLanguage():formatDate(format, result)
    end
 
    return result
end
 
-- Общий синтаксис, с "пасхалия":
m [CalendarData.apiEaster] = function (frame)
    return Easter (frame.args)
end

-- Сокращённый синтаксис, без "пасхалия":
for holiday, _ in pairs (CalendarData.relativeDates) do
    m [holiday] = function (frame)
        local args = frame.args
        args [CalendarData.argEasterOffset] = holiday
        return Easter (args)
    end
end

-- "десятилетие":
local function calculateDecade (year)
    local ret = ""
    local end_of_prev_decade = (year - 1) - (year - 1) % 10
    if year > 0 then
        -- AD:
        ret = tostring (end_of_prev_decade) .. CalendarData.decadeSuffix
    else
        -- BC:
--        end_of_prev_decade = end_of_prev_decade
        ret = tostring (-end_of_prev_decade) .. CalendarData.decadeSuffix
           .. " " .. CalendarData.BC
    end
    return ret        
end

local function loadYearOffset (offset)
    if not offset then
        return true, 0
    end
    local result = tonumber (offset)
    if not result or math.floor (result) ~= result then
        return false, formatCalendarError (CalendarData.errorInvalidYearOffset, offset)
    end
 
    return true, result
end

local function Decade (args)
    local ok
    local year
    ok, year = loadYear (args [CalendarData.argYear])
    if not ok then
        return year
    end
 
    local offset
    ok, offset = loadYearOffset (args [CalendarData.argYearOffset])
    if not ok then
        return offset
    end
  
    return calculateDecade (year + offset)
end

m [CalendarData.apiDecade] = function (frame)
    return Decade (frame.args)
end
 
return m