Module:Time
Documentation for this module may be created at Module:Time/doc
require('strict')
local getArgs = require ('Module:Arguments').getArgs
local tz = {}; -- holds local copy of the specified timezone table from tz_data{}
local cfg = {}; -- for internationalization
--[[--------------------------< I S _ S E T >------------------------------------------------------------------
Whether variable is set or not. A variable is set when it is not nil and not empty.
]]
local function is_set( var )
return not (nil == var or '' == var);
end
--[[--------------------------< S U B S T I T U T E >----------------------------------------------------------
Populates numbered arguments in a message string using an argument table.
]]
local function substitute (msg, args)
return args and mw.message.newRawMessage (msg, args):plain() or msg;
end
--[[--------------------------< E R R O R _ M S G >------------------------------------------------------------
create an error message
]]
local function error_msg (msg, arg)
return substitute (cfg.err_msg, substitute (cfg.err_text[msg], arg))
end
--[[--------------------------< D E C O D E _ D S T _ E V E N T >----------------------------------------------
extract ordinal, day-name, and month from daylight saving start/end definition string as digits:
Second Sunday in March
returns
2 0 3
Casing doesn't matter but the form of the string does:
<ordinal> <day> <any single word> <month> – all are separated by spaces
]]
local function decode_dst_event (dst_event_string)
local ord, day, month;
dst_event_string = dst_event_string:lower(); -- force the string to lower case because that is how the tables above are indexed
ord, day, month = dst_event_string:match ('([%a%d]+)%s+(%a+)%s+%a+%s+(%a+)');
if not (is_set (ord) and is_set (day) and is_set (month)) then -- if one or more of these not set, then pattern didn't match
return nil;
end
return cfg.ordinals[ord], cfg.days[day], cfg.months[month];
end
--[[--------------------------< G E T _ D A Y S _ I N _ M O N T H >--------------------------------------------
Returns the number of days in the month where month is a number 1–12 and year is four-digit Gregorian calendar.
Accounts for leap year.
]]
local function get_days_in_month (year, month)
local days_in_month = {31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31};
year = tonumber (year); -- force these to be numbers just in case
month = tonumber (month);
if (2 == month) then -- if February
if (0 == (year%4) and (0 ~= (year%100) or 0 == (year%400))) then -- is year a leap year?
return 29; -- if leap year then 29 days in February
end
end
return days_in_month [month];
end
--[[--------------------------< G E T _ D S T _ M O N T H _ D A Y >--------------------------------------------
Return the date (month and day of the month) for the day that is the ordinal (nth) day-name in month (second
Friday in June) of the current year
timestamp is today's date-time number from os.time(); used to supply year
timezone is the timezone parameter value from the template call
Equations used in this function taken from Template:Weekday_in_month
]]
local function get_dst_month_day (timestamp, start)
local ord, weekday_num, month;
local first_day_of_dst_month_num;
local last_day_of_dst_month_num;
local days_in_month;
local year;
if true == start then
ord, weekday_num, month = decode_dst_event (tz.dst_begins); -- get start string and convert to digits
else
ord, weekday_num, month = decode_dst_event (tz.dst_ends); -- get end string and convert to digits
end
if not (is_set (ord) and is_set (weekday_num) and is_set (month)) then
return nil; -- could not decode event string
end
year = os.date ('%Y', timestamp);
if -1 == ord then -- j = t + 7×(n + 1) - (wt - w) mod 7 -- if event occurs on the last day-name of the month ('last Sunday of October')
days_in_month = get_days_in_month (year, month);
last_day_of_dst_month_num = os.date ('%w', os.time ({['year']=year, ['month']=month, ['day']=days_in_month}));
return month, days_in_month + 7*(ord + 1) - ((last_day_of_dst_month_num - weekday_num) % 7);
else -- j = 7×n - 6 + (w - w1) mod 7
first_day_of_dst_month_num = os.date ('%w', os.time ({['year']=year, ['month']=month, ['day']=1}))
return month, 7 * ord - 6 + (weekday_num - first_day_of_dst_month_num) % 7; -- return month and calculated date
end
end
--[[--------------------------< G E T _ U T C _ O F F S E T >--------------------------------------------------
Get utc offset in hours and minutes, convert to seconds. If the offset can't be converted return nil.
TODO: return error message?
TODO: limit check this? +/-n hours?
]]
local function get_utc_offset ()
local sign;
local hours;
local minutes;
sign, hours, minutes = mw.ustring.match (tz.utc_offset, '([%+%-±−]?)(%d%d):(%d%d)');
if '-' == sign then sign = -1; else sign = 1; end
if is_set (hours) and is_set (minutes) then
return sign * ((hours * 3600) + (minutes * 60));
else
return nil; -- we require that all timezone tables have what appears to be a valid offset
end
end
--[[--------------------------< M A K E _ D S T _ T I M E S T A M P S >----------------------------------------
Return UTC timestamps for the date/time of daylight saving time events (beginning and ending). These timestamps
will be compared to current UTC time. A dst timestamp is the date/time in seconds UTC for the timezone at the
hour of the dst event.
For dst rules that specify local event times, the timestamp is the sum of:
timestamp = current year + dst_month + dst_day + dst_time (all in seconds) local time
Adjust local time to UTC by subtracting utc_offset:
timestamp = timestamp - utc_offset (in seconds)
For dst_end timestamp, subtract an hour for DST
timestamp = timestamp - 3600 (in seconds)
For dst rules that specify utc event time the process is the same except that utc offset is not subtracted.
]]
local function make_dst_timestamps (timestamp)
local dst_begin, dst_end; -- dst begin and end time stamps
local year; -- current year
local dst_b_month, dst_e_month, dst_day; -- month and date of dst event
local dst_hour, dst_minute; -- hour and minute of dst event on year-dst_month-dst_day
local invert = false; -- flag to pass on when dst_begin month is numerically larger than dst_end month (southern hemisphere)
local utc_offset;
local utc_flag;
year = os.date ('%Y', timestamp); -- current year
utc_offset = get_utc_offset (); -- in seconds
if not is_set (utc_offset) then -- utc offset is a required timezone property
return nil;
end
dst_b_month, dst_day = get_dst_month_day (timestamp, true); -- month and day that dst begins
if not is_set (dst_b_month) then
return nil;
end
dst_hour, dst_minute = tz.dst_time:match ('(%d%d):(%d%d)'); -- get dst time
utc_flag = tz.dst_time:find ('[Uu][Tt][Cc]%s*$'); -- set flag when dst events occur at a specified utc time
dst_begin = os.time ({['year'] = year, ['month'] = dst_b_month, ['day'] = dst_day, ['hour'] = dst_hour, ['min'] = dst_minute}); -- form start timestamp
if not is_set (utc_flag) then -- if dst events are specified to occur at local time
dst_begin = dst_begin - utc_offset; -- adjust local time to utc by subtracting utc offset
end
dst_e_month, dst_day = get_dst_month_day (timestamp, false); -- month and day that dst ends
if not is_set (dst_e_month) then
return nil;
end
if is_set (tz.dst_e_time) then
dst_hour, dst_minute = tz.dst_e_time:match ('(%d%d):(%d%d)'); -- get ending dst time; this one for those locales that use different start and end times
utc_flag = tz.dst_e_time:find ('[Uu][Tt][Cc]%s*$'); -- set flag if dst is pegged to utc time
end
dst_end = os.time ({['year'] = year, ['month'] = dst_e_month, ['day'] = dst_day, ['hour'] = dst_hour, ['min'] = dst_minute}); -- form end timestamp
if not is_set (utc_flag) then -- if dst events are specified to occur at local time
dst_end = dst_end - 3600; -- assume that local end time is DST so adjust to local ST
dst_end = dst_end - utc_offset; -- adjust local time to utc by subtracting utc offset
end
if dst_b_month > dst_e_month then
invert = true; -- true for southern hemisphere eg: start September YYYY end April YYYY+1
end
return dst_begin, dst_end, invert;
end
--[[--------------------------< G E T _ T E S T _ T I M E >----------------------------------------------------
decode ISO formatted date/time into a table suitable for os.time(). Fallback to {{Timestamp}} format.
For testing, this time is UTC just as is returned by the os.time() function.
]]
local function get_test_time (iso_date)
local year, month, day, hour, minute, second;
year, month, day, hour, minute, second = iso_date:match ('(%d%d%d%d)%-(%d%d)%-(%d%d)T(%d%d):(%d%d):(%d%d)');
if not year then
year, month, day, hour, minute, second = iso_date:match ('^(%d%d%d%d)(%d%d)(%d%d)(%d%d)(%d%d)(%d%d)$');
if not year then
return nil; -- test time did not match the specified patterns
end
end
return {['year'] = year, ['month'] = month, ['day'] = day, ['hour'] = hour, ['min'] = minute, ['sec'] = second};
end
--[[----------------------< G E T _ F U L L _ U T C _ O F F S E T >-----------------------------------------------
Creates a standard UTC offset from numerical inputs, for function time to convert to a table. Expected inputs shall have the form:
<sign><hour><separator><portion>
where:
<sign> – optional; one of the characters: '+', '-' (hyphen), '±', '−' (minus); defaults to '+'
<hour> - one or two digits
<separator> - one of the characters '.' or ':'; required when <portion> is included; ignored else
<portion> - optional; one or two digits when <separator> is '.'; two digits else
returns correct utc offset string when input has a correct form; else returns the unmodified input
]]
local function get_full_utc_offset (utc_offset)
local h, m, sep, sign;
local patterns = {
'^([%+%-±−]?)(%d%d?)(%.)(%d%d?)$', -- one or two fractional hour digits
'^([%+%-±−]?)(%d%d?)(:)(%d%d)$', -- two minute digits
'^([%+%-±−]?)(%d%d?)[%.:]?$', -- hours only; ignore trailing separator
}
for _, pattern in ipairs(patterns) do -- loop through the patterns
sign, h, sep, m = mw.ustring.match (utc_offset, pattern);
if h then
break; -- if h is set then pattern matched
end
end
if not h then
return utc_offset; -- did not match a pattern
end
sign = ('' == sign) and '+' or sign; -- sign character is required; set to '+' if not specified
m = ('.' == sep) and ((sep .. m) * 60) or m or 0; -- fractional h to m
return string.format ('utc%s%02d:%02d', sign, h, m);
end
--[[--------------------------< T A B L E _ L E N >------------------------------------------------------------
return number of elements in table
]]
local function table_len (tbl)
local count = 0;
for _ in pairs (tbl) do
count = count + 1;
end
return count;
end
--[[--------------------------< F I R S T _ S E T >------------------------------------------------------------
scans through a list of parameter names that are aliases of each other and returns the value assigned to the
first args[alias] that has a set value; nil else. scan direction is right-to-left (top-to-bottom)
]]
local function first_set (list, args)
local i = 1;
local count = table_len (list); -- get count of items in list
while i <= count do -- loop through all items in list
if is_set( args[list[i]] ) then -- if parameter name in list is set in args
return args[list[i]]; -- return the value assigned to the args parameter
end
i = i + 1; -- point to next
end
end
--[=[-------------------------< T I M E >----------------------------------------------------------------------
This template takes several parameters (some positonal, some not); none are required:
1. the time zone abbreviation/UTC offset (positional, always the first unnamed parameter)
2. a date format flag; second positional parameter or |df=; can have one of several values
3. |dst= when set to 'no' disables dst calculations for locations that do not observe dst – Arizona in MST
4. |timeonly= when set to 'yes' only display the time
5. |dateonly= when set to 'yes' only display the date
6. |hide-refresh = when set to 'yes' removes the refresh link
7. |hide-tz = when set to 'yes' removes the timezone name
8. |unlink-tz = when set to 'yes' unlinks the timzone name
9. |_TEST_TIME_= a specific utc time in ISO date time format used for testing this code
TODO: convert _TEST_TIME_ to |time=?
Timezone abbreviations can be found here: [[List_of_time_zone_abbreviations]]
For custom date format parameters |df-cust=, |df-cust-a=, |df-cust-p= use codes
described here: [[:mw:Help:Extension:ParserFunctions##time]]
]=]
local function time (frame)
local args = getArgs (frame);
local utc_timestamp, timestamp; -- current or _TEST_TIME_ timestamps; timestamp is local ST or DST time used in output
local dst_begin_ts, dst_end_ts; -- DST begin and end timestamps in UTC
local tz_abbr; -- select ST or DST timezone abbreviaion used in output
local time_string; -- holds output time/date in |df= format
local utc_offset;
local invert; -- true when southern hemisphere
local DF; -- date format flag; the |df= parameter
local is_dst_tz;
local data = table.concat ({'Module:Time/data', frame:getTitle():find('sandbox', 1, true) and '/sandbox' or ''}); -- make a data module name; sandbox or live
data = mw.loadData (data); -- load the data module
cfg = data.cfg; -- get the configuration table
local tz_aliases = data.tz_aliases; -- get the aliases table
local tz_data = data.tz_data; -- get the tz data table
local Timeonly = 'yes' == first_set (cfg.aliases['timeonly'], args); -- boolean
local Dateonly = 'yes' == first_set (cfg.aliases['dateonly'], args); -- boolean
if Timeonly and Dateonly then -- invalid condition when both are set
Timeonly, Dateonly = false;
end
local Hide_refresh = 'yes' == first_set (cfg.aliases['hide-refresh'], args);-- boolean
local Hide_tz = 'yes' == first_set (cfg.aliases['hide-tz'], args); -- boolean
local Unlink_tz = 'yes' == first_set (cfg.aliases['unlink-tz'], args); -- boolean
local DST = first_set (cfg.aliases['dst'], args);
local Lang = first_set (cfg.aliases['lang'], args); -- to render in a language other than the local wiki's language
local DF_cust = first_set (cfg.aliases['df-cust'], args); -- custom date/time formats
local DF_cust_a = first_set (cfg.aliases['df-cust-a'], args); -- for am/pm sensitive formats
local DF_cust_p = first_set (cfg.aliases['df-cust-p'], args);
if not ((DF_cust_a and DF_cust_p) or -- DF_cust_a xor DF_cust_p
(not DF_cust_a and not DF_cust_p))then
return error_msg ('bad_df_pair'); -- both are required
end
if args[1] then
args[1] = get_full_utc_offset (args[1]):lower(); -- make lower case because tz table member indexes are lower case
else
args[1] = 'utc'; -- default to utc
end
if mw.ustring.match (args[1], 'utc[%+%-±−]%d%d:%d%d') then -- if rendering time for a UTC offset timezone
tz.abbr = args[1]:upper():gsub('%-', '−'); -- set the link label to upper case and replace hyphen with a minus character (U+2212)
tz.article = tz.abbr; -- article title same as abbreviation
tz.utc_offset = mw.ustring.match (args[1], 'utc([%+%-±−]?%d%d:%d%d)'):gsub('−', '%-'); -- extract the offset value; replace minus character with hyphen
local s, t = mw.ustring.match (tz.utc_offset, '(±)(%d%d:%d%d)'); -- ± only valid for offset 00:00
if s and '00:00' ~= t then
return error_msg ('bad_sign');
end
tz.df = 'iso';
args[1] = 'utc_offsets'; -- spoof to show that we recognize this timezone
else
tz = tz_aliases[args[1]] and tz_data[tz_aliases[args[1]]] or tz_data[args[1]]; -- make a local copy of the timezone table from tz_data{}
if not tz then
return error_msg ('unknown_tz', args[1]); -- if the timezone given isn't in module:time/data(/sandbox)
end
end
DF = first_set (cfg.aliases['df'], args) or args[2] or tz.df or cfg.default_df; -- template |df= overrides typical df from tz properties
DF = DF:lower(); -- normalize to lower case
if not cfg.df_vals[DF] then
return error_msg ('bad_format', DF);
end
if is_set (args._TEST_TIME_) then -- typically used to test the code at a specific utc time
local test_time = get_test_time (args._TEST_TIME_);
if not test_time then
return error_msg ('test_time');
end
utc_timestamp = os.time(test_time);
else
utc_timestamp = os.time (); -- get current server time (UTC)
end
utc_offset = get_utc_offset (); -- utc offset for specified timezone in seconds
timestamp = utc_timestamp + utc_offset; -- make local time timestamp
if 'no' == DST then -- for timezones that DO observe dst but for this location ...
tz_abbr = tz.abbr; -- ... dst is not observed (|dst=no) show time as standard time
elseif 'always' == DST then -- if needed to always display dst time
timestamp = timestamp + 3600; -- add a hour for dst
tz_abbr = tz.dst_abbr; -- dst abbreviation
else
if is_set (tz.dst_begins) and is_set (tz.dst_ends) and is_set (tz.dst_time) then -- make sure we have all of the parts
dst_begin_ts, dst_end_ts, invert = make_dst_timestamps (timestamp); -- get begin and end dst timestamps and invert flag
if nil == dst_begin_ts or nil == dst_end_ts then
return error_msg ('bad_dst');
end
if invert then -- southern hemisphere; use beginning and ending of standard time in the comparison
if utc_timestamp >= dst_end_ts and utc_timestamp < dst_begin_ts then -- is current date time standard time?
tz_abbr = tz.abbr; -- standard time abbreviation
else
timestamp = timestamp + 3600; -- add an hour
tz_abbr = tz.dst_abbr; -- dst abbreviation
end
else -- northern hemisphere
if utc_timestamp >= dst_begin_ts and utc_timestamp < dst_end_ts then -- all timestamps are UTC
timestamp = timestamp + 3600; -- add an hour
tz_abbr = tz.dst_abbr;
else
tz_abbr = tz.abbr;
end
end
elseif is_set (tz.dst_begins) or is_set (tz.dst_ends) or is_set (tz.dst_time) then -- if some but not all not all parts then emit error message
return error_msg ('bad_def', args[1]:upper());
else
tz_abbr = tz.abbr; -- dst not observed for this timezone
end
end
if Dateonly then
if 'iso' == DF then -- |df=iso
DF = 'iso_date';
elseif DF:find ('^dmy') or 'y' == DF then -- |df=dmy, |df=dmy12, |df=dmy24, |df=y
DF = 'dmy_date';
else
DF = 'mdy_date'; -- default
end
elseif Timeonly or DF:match ('^%d+$') then -- time only of |df= is just digits
DF = table.concat ({'t', DF:match ('%l*(12)') or '24'}); -- |df=12, |df=24, |df=dmy12, |df=dmy24, |df=mdy12, |df=mdy24; default to t24
elseif 'y' == DF or 'dmy24' == DF then
DF = 'dmy';
elseif 'mdy24' == DF then
DF = 'mdy';
end
local dformat;
if is_set (DF_cust) then
dformat=DF_cust;
elseif is_set (DF_cust_a) then -- custom format is am/pm sensitive?
if 'am' == os.date ('%P', timestamp) then -- if current time is am
dformat = DF_cust_a; -- use custom am format
else
dformat = DF_cust_p; -- use custom pm format
end
else
dformat = cfg.format[DF]; -- use format from tables or from |df=
end
time_string = frame:callParserFunction ({name='#time', args={dformat, '@'..timestamp, Lang}});
if Lang then
time_string = table.concat ({ -- bidirectional isolation of non-local language; yeah, rather brute force but simple
'<bdi lang="', -- start of opening bdi tag
Lang, -- insert rendered language code
'">', -- end of opening tag
time_string, -- insert the time string
'</bdi>' -- and close the tag
});
end
if not is_set (tz.article) then -- if some but not all not all parts then emit error message
return error_msg ('bad_def', args[1]:upper());
end
local refresh_link = (Hide_refresh and '') or
table.concat ({
' <span class="plainlinks" style="font-size:85%;">[[', -- open span
mw.title.getCurrentTitle():fullUrl({action = 'purge'}), -- add the a refresh link url
' refresh]]</span>', -- close the span
});
local tz_tag = (Hide_tz and '') or
((Unlink_tz and table.concat ({' ', tz_abbr})) or -- unlinked
table.concat ({' [[', tz.article, '|', tz_abbr, ']]'})); -- linked
return table.concat ({time_string, tz_tag, refresh_link});
end
--[[--------------------------< E X P O R T E D F U N C T I O N S >------------------------------------------
]]
return {time = time}