Dealing with calendars can be pretty difficult. Since I recently wrote a script in Lua to be my personal assistant, processing calendars, todo lists, mailing l

Dealing with calendars can be pretty difficult. Since I recently wrote a script in Lua to be my personal assistant, processing calendars, todo lists, mailing lists, etc., here’s a Lua form of the code to calculate the day of week. This is accurate for any Georgian date: -- Calculate the day of the week -- Input: year, month, day (e.g. 2022,9,16) -- Output: day of week (0 = Sunday, 6 = Saturday) function dayOfWeek(year, month, day) -- Tomohiko Sakamoto algorithm local monthX = {0, 3, 2, 5, 0, 3, 5, 1, 4, 6, 2, 4} if month < 3 then year = year - 1 end local yearX = (year + math.floor(year / 4) - math.floor(year / 100) + math.floor(year / 400)) local out = yearX + monthX[month] + day out = out % 7 return out end