[db48x]

But they‘re mostly trivial variations of each other, or durations that nobody uses at all.

[tim--]

That's the problem though. If you don't support the durations that nobody uses, then you can't fully support ISO8601 dates.

Every trivial variation is another if/switch statement.

[db48x]

Durations are not used in places that need a timestamp, and visa versa. More applications need timestamps than need durations.