I have seen many people downplaying the complexity of a datetime library. "Just use UTC/Unix time as an internal representation", "just represent duration as nanoseconds", "just use offset instead of timezones", and on and on
For anyone having that thought, try reading through the design document of Jiff (https://github.com/BurntSushi/jiff/blob/master/DESIGN.md), which, as all things burntsushi do, is excellent and extensive. Another good read is the comparison with (mainly) chrono, the de facto standard datetime library in Rust: https://docs.rs/jiff/latest/jiff/_documentation/comparison/i...
Stuffs like DST arithmetic (that works across ser/de!), roundable duration, timezone aware calendar arithmetic, retrospective timezone conflict detection (!), etc. all contribute to a making the library correct, capable, and pleasant to use. In my experience, chrono is a very comprehensive and "correct" library, but it is also rigid and not very easy to use.
For anyone having that thought, try reading through the design document of Jiff (https://github.com/BurntSushi/jiff/blob/master/DESIGN.md), which, as all things burntsushi do, is excellent and extensive. Another good read is the comparison with (mainly) chrono, the de facto standard datetime library in Rust: https://docs.rs/jiff/latest/jiff/_documentation/comparison/i...
Stuffs like DST arithmetic (that works across ser/de!), roundable duration, timezone aware calendar arithmetic, retrospective timezone conflict detection (!), etc. all contribute to a making the library correct, capable, and pleasant to use. In my experience, chrono is a very comprehensive and "correct" library, but it is also rigid and not very easy to use.