Module:Parsedate

-- Helper functions for Template:Start date -- This will accept a start_date returning a string that: -- for a valid date, wraps a hidden copy of the date in ISO format in a microformat -- returns start_date -- See Module:Age for other date functions

local p = {}

-- This parses a valid date string into a Lua date table and returns a hidden microformat -- Only valid for dates after 31 A.D.

p.parse_date = function(frame) local strdate = mw.text.trim(frame.args[1] or "") local invalid = false local wrd = {} local num = {} -- this is a list of indices of wrd where the value is a number < 32 local yr = {} -- this is a list of indices of wrd where the value is a number > 31 local mth = {} -- this is a list of indices of wrd where the value is an alphabetical month

for w in string.gmatch(strdate, "%w+") do   -- catch numbers like '27th' local found1, found2 = string.find(w, "%d+") if found1 then w = string.sub(w, found1, found2) end -- now we can store what we found wrd[#wrd+1] = w   if tonumber(w) then if tonumber(w) < 32 then num[#num+1] = #wrd else yr[#yr+1] = #wrd end end local s = string.sub(w, 1, 3) -- the first 3 chars of w   local f1 = string.find("Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec", s, 1, true) if f1 then mth[#mth+1] = #wrd wrd[#wrd] = (f1 + 3)/4 -- replace Jan with 1, Feb with 2, etc.   end end

-- at this point #wrd contains the number of words and numbers and wrd contains the words and numbers -- num is an index of day or numeric month candidates -- yr is an index of year candidates -- mth is an index of alphabetic month candidates

-- let's take out the garbage if not yr[1] then invalid = true end -- no year if not num[1] then invalid = true end -- no day if not mth[1] then -- no alpha month: if not num[2] then invalid = true -- no month else -- two numbers, but: if not yr[1] then invalid = true -- no year else -- two numbers and a year, but: if yr[1] > num[1] then invalid = true end -- year is not first, so date not in yyyy--mm--dd format end end end local msg -- the output string if invalid then msg = strdate else -- if we have an alpha month, then it's either dmy or mdy. Otherwise it may be yyyy-mm-dd: local ymddate local dt = {} if mth[1] then -- str_date contains an alpha month, so dmy or mdy work the same now. -- Put the first occurrence of each into the date table: dt.year = wrd[yr[1]] dt.month = wrd[mth[1]] dt.day = wrd[num[1]] else -- yyyymmdd has to have numeric month before numeric day dt.year = wrd[yr[1]] dt.month = wrd[num[1]] dt.day = wrd[num[2]] end ymddate = os.date("%Y-%m-%d", os.time(dt)) msg = ' &#160;( ' .. ymddate .. ' ) ' .. strdate end return msg end

return p