Module:Date: Difference between revisions

    (enhanced version of Module:Age which will be replaced by this module as it provides generic date functions)
     
    (formatted output and strftime)
    Line 45: Line 45:
    local function is_leap_year(year, calname)
    local function is_leap_year(year, calname)
    -- Return true if year is a leap year.
    -- Return true if year is a leap year.
    if calname == 'JCAL' then
    if calname == 'Julian' then
    return year % 4 == 0
    return year % 4 == 0
    end
    end
    Line 66: Line 66:
    -- http://www.tondering.dk/claus/cal/julperiod.php#formula
    -- http://www.tondering.dk/claus/cal/julperiod.php#formula
    -- Testing shows this works for all dates from year -9999 to 9999!
    -- Testing shows this works for all dates from year -9999 to 9999!
    -- JDN 0 is the 24-hour period starting at noon UTC on
    -- JDN 0 is the 24-hour period starting at noon UTC on Monday
    --    1 January 4713 BC  = (-4712, 1, 1)  Julian calendar
    --    1 January 4713 BC  = (-4712, 1, 1)  Julian calendar
    --  24 November 4714 BC = (-4713, 11, 24) Gregorian calendar
    --  24 November 4714 BC = (-4713, 11, 24) Gregorian calendar
    Line 76: Line 76:
    local a = floor((14 - date.month)/12)
    local a = floor((14 - date.month)/12)
    local y = date.year + 4800 - a
    local y = date.year + 4800 - a
    if date.calname == 'JCAL' then
    if date.calname == 'Julian' then
    offset = floor(y/4) - 32083
    offset = floor(y/4) - 32083
    else
    else
    Line 104: Line 104:
    local jd = date.jd
    local jd = date.jd
    local limits  -- min/max limits for date ranges −9999-01-01 to 9999-12-31
    local limits  -- min/max limits for date ranges −9999-01-01 to 9999-12-31
    if calname == 'JCAL' then
    if calname == 'Julian' then
    limits = { -1931076.5, 5373557.5 }
    limits = { -1931076.5, 5373557.49999 }
    elseif calname == 'GCAL' then
    elseif calname == 'Gregorian' then
    limits = { -1930999.5, 5373484.5 }
    limits = { -1930999.5, 5373484.49999 }
    else
    else
    limits = { 1, 0 }  -- impossible
    limits = { 1, 0 }  -- impossible
    end
    end
    if not (limits[1] <= jd and jd < limits[2]) then
    if not (limits[1] <= jd and jd <= limits[2]) then
    date.isvalid = false
    date.isvalid = false
    return
    return
    Line 138: Line 138:
    end
    end
    local b, c
    local b, c
    if calname == 'JCAL' then
    if calname == 'Julian' then
    b = 0
    b = 0
    c = jdn + 32082
    c = jdn + 32082
    Line 154: Line 154:
    end
    end


    local function date_text(date)
    local function make_option_table(options)
    -- Return formatted string from given date.
    -- If options is a string, return a table with its settings.
    -- Otherwise return options (it should already be a table).
    if type(options) == 'string' then
    -- Example: 'am:AM era:BC'
    local result = {}
    for item in options:gmatch('%S+') do
    local lhs, rhs = item:match('^(%w+):(.*)$')
    if lhs then
    result[lhs] = rhs
    end
    end
    return result
    end
    return options
    end
     
    local function strftime(date, format, options)
    -- Return date formatted as a string using codes similar to those
    -- in the C strftime library function.
    if not date.isvalid then
    if not date.isvalid then
    return '(invalid)'
    return '(invalid)'
    end
    end
    local time = ''
    local codes = {
    if date.hastime then
    a = { field = 'dayabbr' },
    if date.second > 0 then
    A = { field = 'dayname' },
    time = string.format(' %02d:%02d:%02d',
    b = { field = 'monthabbr' },
    date.hour,
    B = { field = 'monthname' },
    date.minute,
    u = { fmt = '%d'  , field = 'dowiso' },
    date.second
    w = { fmt = '%d'  , field = 'dow' },
    )
    d = { fmt = '%02d', field = 'day' },
    else
    m = { fmt = '%02d', field = 'month' },
    time = string.format(' %02d:%02d',
    Y = { fmt = '%04d', field = 'year' },
    date.hour,
    H = { fmt = '%02d', field = 'hour' },
    date.minute
    M = { fmt = '%02d', field = 'minute' },
    )
    S = { fmt = '%02d', field = 'second' },
    j = { fmt = '%03d', field = 'doy' },
    I = { fmt = '%02d', field = 'hour', special = 'hour12' },
    p = { field = 'hour', special = 'am' },
    X = { fmt = '%02d:%02d:%02d', field = 'hour', special = 'hms' },
    ['-d'] = { fmt = '%d', field = 'day' },
    ['-m'] = { fmt = '%d', field = 'month' },
    ['-Y'] = { fmt = '%d', field = 'year' },
    ['-j'] = { fmt = '%d', field = 'doy' },
    }
    options = make_option_table(options or date.options)
    local amopt = options.am
    local eraopt = options.era
    local function replace_code(id)
    local code = codes[id]
    if code then
    local fmt = code.fmt
    local value = date[code.field]
    local special = code.special
    if special then
    if special == 'hour12' then
    value = value % 12
    value = value == 0 and 12 or value
    elseif special == 'hms' then
    return string.format(fmt, value, date.minute, date.second)
    elseif special == 'am' then
    local ap = ({
    ['a.m.'] = { 'a.m.', 'p.m.' },
    ['AM'] = { 'AM', 'PM' },
    ['A.M.'] = { 'A.M.', 'P.M.' },
    })[amopt] or { 'am', 'pm' }
    return value < 12 and ap[1] or ap[2]
    end
    end
    if code.field == 'year' then
    if eraopt == 'BCMINUS' or eraopt == 'BCNEGATIVE' then
    local sign
    if value >= 0 then
    sign = ''
    else
    sign = eraopt == 'BCMINUS' and MINUS or '-'
    value = -value
    end
    return sign .. string.format(fmt, value)
    end
    if value <= 0 then
    value = 1 - value
    end
    end
    return fmt and string.format(fmt, value) or value
    end
    end
    end
    end
    local y = date.year
    local function replace_property(id)
    local sign = ''
    local result = date[id]
    if y < 0 then
    if type(result) == 'string' then
    sign = MINUS
    if id == 'era' and result ~= '' then
    y = -y
    -- Assume era follows a date.
    return '&nbsp;' .. result
    end
    return result
    end
    if type(result) == 'number' then
    return tostring(result)
    end
    if type(result) == 'boolean' then
    return result and '1' or '0'
    end
    -- This occurs, for example, if id is the name of a function.
    return nil
    end
    end
    return string.format('%s%04d-%02d-%02d%s',
    local PERCENT = '\127PERCENT\127'
    sign,
    return (format
    y,
    :gsub('%%%%', PERCENT)
    date.month,
    :gsub('%%{(%w+)}', replace_property)
    date.day,
    :gsub('%%(-?%a)', replace_code)
    time
    :gsub(PERCENT, '%%')
    )
    )
    end
    end
    local function date_text(date, fmt, options)
    -- Return formatted string from given date.
    if not (type(date) == 'table' and date.isvalid) then
    return '(invalid)'
    end
    if type(fmt) ~= 'string' then
    fmt = '%Y-%m-%d'
    if date.hastime then
    if date.second > 0 then
    fmt = fmt .. ' %H:%M:%S'
    else
    fmt = fmt .. ' %H:%M'
    end
    end
    return strftime(date, fmt, options or { era = 'BCMINUS' })
    end
    if fmt:find('%', 1, true) then
    return strftime(date, fmt, options)
    end
    local t = collection()
    for item in fmt:gmatch('%S+') do
    local f
    if item == 'hm' then
    f = '%H:%M'
    elseif item == 'hms' then
    f = '%H:%M:%S'
    elseif item == 'ymd' then
    f = '%Y:%m:%d%{era}'
    elseif item == 'mdy' then
    f = '%B %-d, %Y%{era}'
    elseif item == 'dmy' then
    f = '%-d %B %Y%{era}'
    else
    return '(invalid format)'
    end
    t:add(f)
    end
    return strftime(date, t:join(' '), options)
    end
    local day_info = {
    -- 0=Sun to 6=Sat
    [0] = { 'Sun', 'Sunday' },
    { 'Mon', 'Monday' },
    { 'Tue', 'Tuesday' },
    { 'Wed', 'Wednesday' },
    { 'Thu', 'Thursday' },
    { 'Fri', 'Friday' },
    { 'Sat', 'Saturday' },
    }
    local month_info = {
    -- 1=Jan to 12=Dec
    { 'Jan', 'January' },
    { 'Feb', 'February' },
    { 'Mar', 'March' },
    { 'Apr', 'April' },
    { 'May', 'May' },
    { 'Jun', 'June' },
    { 'Jul', 'July' },
    { 'Aug', 'August' },
    { 'Sep', 'September' },
    { 'Oct', 'October' },
    { 'Nov', 'November' },
    { 'Dec', 'December' },
    }


    local function month_number(text)
    local function month_number(text)
    Line 242: Line 388:
    return nil
    return nil
    end
    end
    local era_text = {
    -- options.era = { year<0  , year>0 }
    ['BCMINUS']    = { MINUS  , ''    },
    ['BCNEGATIVE'] = { '-'    , ''    },
    ['BC']        = { 'BC'    , ''    },
    ['B.C.']      = { 'B.C.'  , ''    },
    ['BCE']        = { 'BCE'  , ''    },
    ['B.C.E.']    = { 'B.C.E.', ''    },
    ['AD']        = { 'BC'    , 'AD'  },
    ['A.D.']      = { 'B.C.'  , 'A.D.' },
    ['CE']        = { 'BCE'  , 'CE'  },
    ['C.E.']      = { 'B.C.E.', 'C.E.' },
    }


    -- Metatable for some operations on dates.
    -- Metatable for some operations on dates.
    -- For Lua 5.1, __lt does not work if the metatable is an anonymous table.
    -- For Lua 5.1, __lt does not work if the metatable is an anonymous table.
    local Date  -- forward declaration
    local datemt = {
    local datemt = {
    __eq = function (lhs, rhs)
    __eq = function (lhs, rhs)
    Line 263: Line 424:
    __index = function (self, key)
    __index = function (self, key)
    local value
    local value
    if key == 'jd' or key == 'jdz' then
    if key == 'dayabbr' then
    value = day_info[self.dow][1]
    elseif key == 'dayname' then
    value = day_info[self.dow][2]
    elseif key == 'dow' then
    value = (self.jd + 1) % 7  -- day-of-week 0=Sun to 6=Sat
    elseif key == 'dowiso' then
    value = (self.jd % 7) + 1  -- ISO day-of-week 1=Mon to 7=Sun
    elseif key == 'doy' then
    local first = Date(self.year, 1, 1, self.calname).jd
    value = self.jd - first + 1  -- day-of-year 1 to 366
    elseif key == 'era' then
    -- Era text from year and options.
    local eraopt = self.options.era
    local sign
    if self.year == 0 then
    sign = (eraopt == 'BCMINUS' or eraopt == 'BCNEGATIVE') and 2 or 1
    else
    sign = self.year > 0 and 2 or 1
    end
    value = era_text[eraopt][sign]
    elseif key == 'gsd' then
    -- GSD = 1 from 00:00:00 to 23:59:59 on 1 January 1 AD Gregorian calendar,
    -- which is JDN = 1721426, and is from jd 1721425.5 to 1721426.49999.
    value = math.floor(self.jd - 1721424.5)
    elseif key == 'jd' or key == 'jdz' then
    local jd, jdz = julian_date(self)
    local jd, jdz = julian_date(self)
    rawset(self, 'jd', jd)
    rawset(self, 'jd', jd)
    rawset(self, 'jdz', jdz)
    rawset(self, 'jdz', jdz)
    return key == 'jd' and jd or jdz
    return key == 'jd' and jd or jdz
    elseif key == 'gsd' then
    -- GSD = 1 from 00:00:00 to 23:59:59 on 1 January 1 AD Gregorian calendar,
    -- which is JDN = 1721426, and is from jd 1721425.5 to 1721426.49999.
    value = math.floor(self.jd - 1721424.5)
    elseif key == 'is_leap_year' then
    elseif key == 'is_leap_year' then
    value = is_leap_year(self.year, self.calname)
    value = is_leap_year(self.year, self.calname)
    elseif key == 'monthabbr' then
    value = month_info[self.month][1]
    elseif key == 'monthname' then
    value = month_info[self.month][2]
    end
    end
    if value ~= nil then
    if value ~= nil then
    Line 294: Line 480:
    Date('04:30:59 1 April 1995', 'julian')
    Date('04:30:59 1 April 1995', 'julian')
    ]]
    ]]
    local function Date(...)
    function Date(...) -- for forward declaration above
    -- Return a table to hold a date assuming a uniform calendar always applies (proleptic).
    -- Return a table to hold a date assuming a uniform calendar always applies (proleptic).
    -- If invalid, return an empty table which is regarded as invalid.
    -- If invalid, return an empty table which is regarded as invalid.
    local calendars = { julian = 'JCAL', Julian = 'JCAL', gregorian = 'GCAL', Gregorian = 'GCAL' }
    local calendars = { julian = 'Julian', gregorian = 'Gregorian' }
    local result = {
    local result = {
    isvalid = false,   -- false avoids __index lookup
    isvalid = false, -- false avoids __index lookup
    calname = 'GCAL',  -- default is Gregorian calendar
    calname = 'Gregorian',  -- default is Gregorian calendar
    hastime = false,   -- true if input sets a time
    hastime = false, -- true if input sets a time
    hour = 0,         -- always set hour/minute/second so don't have to handle nil
    hour = 0, -- always set hour/minute/second so don't have to handle nil
    minute = 0,
    minute = 0,
    second = 0,
    second = 0,
    Line 308: Line 494:
    return days_in_month(self.year, month, self.calname)
    return days_in_month(self.year, month, self.calname)
    end,
    end,
    -- Valid option settings are:
    -- am: 'am', 'a.m.', 'AM', 'A.M.'
    -- era: 'BCMINUS', 'BCNEGATIVE', 'BC', 'B.C.', 'BCE', 'B.C.E.', 'AD', 'A.D.', 'CE', 'C.E.'
    options = { am = 'am', era = 'BC' },
    text = date_text,
    text = date_text,
    }
    }
    Line 315: Line 505:
    for _, v in ipairs({...}) do
    for _, v in ipairs({...}) do
    v = strip_to_nil(v)
    v = strip_to_nil(v)
    local vlower = type(v) == 'string' and v:lower() or nil
    if v == nil then
    if v == nil then
    -- Ignore empty arguments after stripping so modules can directly pass template parameters.
    -- Ignore empty arguments after stripping so modules can directly pass template parameters.
    elseif calendars[v] then
    elseif calendars[vlower] then
    result.calname = calendars[v]
    result.calname = calendars[vlower]
    else
    else
    local num = tonumber(v)
    local num = tonumber(v)
    Line 376: Line 567:
    result.hastime = true
    result.hastime = true
    end
    end
    result.calname = 'GCAL'  -- ignore any given calendar name
    result.calname = 'Gregorian'  -- ignore any given calendar name
    result.isvalid = true
    result.isvalid = true
    elseif argtype == 'setdate' then
    elseif argtype == 'setdate' then
    Line 418: Line 609:
    -- TODO Replace with something using Julian dates?
    -- TODO Replace with something using Julian dates?
    --      Who checks for isvalid()?
    --      Who checks for isvalid()?
    --      Handle calname == 'JCAL'
    --      Handle calname == 'Julian'
    local calname = 'GCAL'  -- TODO fix
    local calname = 'Gregorian'  -- TODO fix
    local isnegative
    local isnegative
    if date2 < date1 then
    if date2 < date1 then
    Retrieved from "https://nonbinary.wiki/wiki/Module:Date"