> On Mar 28, 2016, at 5:33 PM, Brent Royal-Gordon <[email protected]> > wrote: > >>> Floating-point seconds (as NSTimeIntervals) are the natural >>> Strideable.Stride, but it's not particularly clear to me that you want 1 >>> second to be a default stride. It's the default you would guess, but it's >>> not actually a particularly useful default. >> >> Any fixed-time-period stride with dates is fraught with peril. Not every day >> is 24 hours, not every minute is 60 seconds, etc. Working with dates >> requires enough special domain knowledge that I think it'd be harmful to try >> to genericize numeric concepts over it. > > While this is true, "ten seconds from now" is always ten seconds from now, > and "seconds between date1 and date2" is always the same number of seconds. > There is a basic level of time measurement and manipulation which is > completely independent of time zones and calendars; that's what NSDate and > NSTimeInterval represent. They are needed fairly often, and they are > perfectly compatible with Strideable's semantics.
Perhaps, but if you make Date strideable by seconds and automatically receive a bunch of utility methods based on that, then it becomes really tempting to abuse absolute time periods, or to accidentally misuse generic Strideable utilities instead of calendar-aware ones. We don't make String a sequence for similar reasons (though perhaps, by analogy to String, there could be `seconds`/`days`/`solarMonths`/`lunarMonths`/etc. views that are Strideable). -Joe _______________________________________________ swift-evolution mailing list [email protected] https://lists.swift.org/mailman/listinfo/swift-evolution
