on Wed Mar 30 2016, Joe Groff <jgroff-AT-apple.com> wrote: >> On Mar 30, 2016, at 8:50 AM, Dave Abrahams <[email protected]> wrote: >> >> >> on Tue Mar 29 2016, Joe Groff <jgroff-AT-apple.com> wrote: >> > >>>> 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). >> >> Except that collections aren't Strideable. A strideable type is a >> value that has an implied unit of measure so that you can offset it >> without reference to any collection. > > Who said anything about collections?
That's what those views are. -- Dave _______________________________________________ swift-evolution mailing list [email protected] https://lists.swift.org/mailman/listinfo/swift-evolution
