[isidor3]

> having one or two days per year which are part of no month is stupid > having one or two days per year with no day of the week is asinine

These don't sound like real reasons to me. If it costs having a 13th month with just a few days in it or a NO_DAY_OF_WEEK constant in my DAYS_OF_WEEK enum, I'd take it if it meant all of the weirdness was limited to a few days always located at the end of the year. Sounds like a convenient place to put leap seconds as well! While you're at it, make those days holidays for most people, so that when tech inevitably breaks due to the weirdness, those of us who get paged for such things can fix them in peace before the rest of the world starts back up a few days later.

[msla]

> These don't sound like real reasons to me.

They are if you have to write date-handling code or, worse, use the date-handling code of others.

Date-handling code is hard enough without NULLs.

[ketzu]

This does not only concern code, but regulation, tradition, contracts etc. The mutual understanding of weeks, days, months of roughly equal lengths is baked into a lot of our things and it's not enough to change it in some header file/law to clean up the rest.

[twic]

The Romans at one point had a setup where a year was 38 8-day weeks plus a bunch of days over winter when nobody is up to much so there's no point having weeks.

https://en.wikipedia.org/wiki/Nundinae