Common Calendrical Fallacies

I've encountered just about every item on this list working on my Apple Watch complication, Better Day[1], which supports 11 calendar systems in 21 languages. The funny thing is, the last item on this list — always use ICU through the NSCalendar API — is the exact conclusion I arrived at, and one that I preach to anyone who will listen. Especially with modern Swift syntax, complex questions like "what's the current day of the year" end up having simple…

This comes off as very "well akchtually"; more snarky than helpful. A great example: >It is normal that the Sept-, Oct-, Nov-, and Dec- months are numbered 9, 10, 11, and 12 >False. This is very weird. They used to be months 7, 8, 9, and 10, but some reform to the Roman calendar back in the day resulted in the creation of January and February, which messed everything up. No software project cares what the calendar looked like during…

This is the sort of thing that enabled me to do an entire 30 minute programming conference talk on Timekeeping (both calendrical and chronological) and how it works outside computers, and what to do when your programming the computer if you want to hedge your bets and try and get it right (or as right as you need it to be) Most people just internalise the 24hr clock mental model and then whatever version of remembering days, weeks and months…