-- For Google Code In 2018 - Lua Task 7 - Date formatting
local p=
p.valid=function(day,month,year) day,month,year=tonumber(day),tonumber(month),tonumber(year) local lengths= local long=0 if year
nil then return true end if type(month)~='number' or math.floor(month)~=month or month<1 or month>12 then return false end if day
2 then if year%400
0 then long=28 elseif year%4
p.testvalid=function(frame) return p.valid(frame.args.day,frame.args.month,frame.args.year)end
p.convert=function(frame) local indate=frame.args.date local day,month,year,era,inform,circa,outdate=nil local monthregex= local monthnames= --parse indate -> inform, day, month, year; then check if valid --first try: parse as some iso-like format local num1,num2,num3,era=string.match(indate,"(%d+)%D+(%d+)%D+(%d+)") if p.valid(num3,num2,num1) then day,month,year,inform=num3,num2,num1,"iso" else if p.valid(num1,num2,num3) then day,month,year,inform=num1,num2,num3,"iso" else if p.valid(num2,num1,num3) then day,month,year,inform=num2,num1,num3,"iso" else if p.valid(num3,num1,num2) then day,month,year,inform=num3,num1,num2,"iso" else if p.valid(num1,num3,num2) then day,month,year,inform=num1,num3,num2,"iso" else if p.valid(num2,num3,num1) then day,month,year,inform=num2,num3,num1,"iso" else if num1~=nil and num2~=nil and num3~=nil then return "Invalid entry" end --second try: parse as some dmy-like format local num4,num5,mon1=nil for i=1,12 do num4,num5=string.match(indate,"(%d+)%D+"..monthregex[i].."%D+(%d+)") if num4~=nil then mon1=i break end end if p.valid(num4,mon1,num5) then day,month,year,inform=num4,mon1,num5,"dmy" else if p.valid(num5,mon1,num4) then day,month,year,inform=num5,mon1,num4,"dmy" else if num4~=nil and mon1~=nil and num5~=nil then return "Invalid entry" end --third try: parse as some mdy-like format local num6,num7,mon2=nil for i=1,12 do num6,num7=string.match(indate,monthregex[i].."%D+(%d+)%D+(%d+)") if num6~=nil then mon2=i break end end if p.valid(num6,mon2,num7) then day,month,year,inform=num6,mon2,num7,"mdy" else if p.valid(num7,mon2,num6) then day,month,year,inform=num7,mon2,num6,"mdy" else if num6~=nil and mon2~=nil and num7~=nil then return "Invalid entry" end --fourth try: parse as month,year-like format local num8,mon3=nil for i=1,12 do num8=string.match(indate,monthregex[i].."%D+(%d+)") if num8~=nil then mon3=i break end end if p.valid(nil,mon3,num8) then month,year,inform=mon3,num8,"month and year" else if mon3~=nil and num8~=nil then return "Invalid entry" end --(the unmentioned case: day and month) local num9,mon4=nil for i=1,12 do num9=string.match(indate,"(%d+)%D+"..monthregex[i]) if num9~=nil then mon4=i break end end if mon4~=nil and p.valid(num9,mon4,2016) then day,month,inform=num9,mon4,"day and month" else if p.valid(nil,mon4,num9) then month,year,inform=mon4,num9,"month and year" else if mon4~=nil and num9~=nil then return "Invalid entry" end --fifth try: parse as year if string.match(indate,"(%d+)%D*[^% %d]%D*(%d+)") then return "Invalid entry" end local num0=string.match("A"..indate,".*%D(%d+)") if p.valid(nil,nil,num0) then year,inform=num0,"year" else return "Invalid entry" end end end end end end end end end end end end end end -- ends from all the elses --get era if string.find(indate,"BCE") then era=" BCE" elseif string.find(indate,"BC") then era=" BC" elseif string.find(indate,"CE") then era=" CE" elseif string.find(indate,"AD") then era=" AD" else era="" end --get uncertainty if string.match(indate,"around") then circa="circa " elseif string.match(indate,"uncertain") then circa="circa " elseif string.match(indate,"about") then circa="circa " elseif string.match(indate,"approx") then circa="circa " elseif string.match(indate,"circa") then circa="circa " elseif string.match(indate,"ca%.") then circa="circa " else circa="" end --convert output date to input format -> outdate local outform=frame.args.format or inform day,month,year=tonumber(day),tonumber(month),tonumber(year) outdate = "" if outform
" BC" or era
"dmy" then outdate = day.." "..monthnames[month]..year..era end if outform
"month and year" then outdate = monthnames[month]..year..era end if outform
"year" then outdate = year..era end outdate = circa..outdate return outdateend
return p