TIL: Sweden had February 30 in 1712 https://en.wikipedia.org/wiki/1712_in_Sweden , so I decided to see how chrono handled that.
use chrono::TimeZone;
use chrono_tz::Europe::Stockholm;
fn main() {
let feb30 = Stockholm.ymd(1712,2,30);
println!("Date: {:?}", feb30);
}
target/debug/feb30
thread 'main' panicked at /home/snaggen/.cargo/registry/src/index.crates.io-6f17d22bba15001f/chrono-0.4.34/src/offset/mod.rs:252:40:
No such local time
note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace
Result (as expected): Not well! 😄
I also tested Java with
ZonedDateTime feb30 = ZonedDateTime.of(1712,2,30, 0,0,0,0, ZoneId.of("Europe/Stockholm"));
with simmilar result
java.time.DateTimeException: Invalid date 'FEBRUARY 30'
So, lets take a minute of silence for all the programmers of history related software, may the spagetti monster have mercy on their souls.
I wasn't clear enough. But in a contry where the sun rise at 20:00, the weekday looks like:
And phares like "let's meet on Tuesday“ without hour indication could either mean end of day 1 or start of day 2. Likewise "let's meet the 20th” (assuming the 20th is a Tuesday) could either mean end of day 1 or beggining of day 2.
--
And alternative be to have
Which solve the issue of "let's meet on Tuesday”, but not “let's meet the 20th”.
Yes, that's one actual problem that is not covered by everyday speech as it is in use today.
I think it would be very quickly solved by language evolution. E.g. we'd switch to something like "the evening on the 20th" or "the third day next week" (weeks are defined by the presence of weekends, just like they are today). But nonetheless it's a valid argument.
Edit: even today weekends cover multiple days. However you define a weekend now can probably be used to define a day in the global UTC system.