Re: NSDate without time portion
Re: NSDate without time portion
- Subject: Re: NSDate without time portion
- From: mmalc Crawford <email@hidden>
- Date: Tue, 05 Jan 2010 13:43:58 -0800
On Jan 5, 2010, at 1:35 pm, Kyle Sluder wrote:
> On Tue, Jan 5, 2010 at 1:23 PM, mmalc Crawford <email@hidden> wrote:
>> An NSDate object represent a single point in time -- you can think of it basically as a wrapper for an NSTimeInterval from the reference date. If you want to create components from the date, then you must do so with respect to a particular calendar *and time zone*... This is of course possible, but then you have to be careful about always using the same combination of calendar and time zone to create the components and recreate the date from the components.
>
> I believe that Quincey's argument is that it is conceptually
> inaccurate in most cases to think of a point in time as simply an
> interval from a reference date. I agree that in contexts where words
> like "today" are meaningful, he's probably right. Especially in
> calendaring/scheduling apps. Given the number of people who struggle
> with the concept of daylight saving time, I am not surprised that I
> have yet to meet a non-technical person who could conceptualize a
> "point in time" independently of a calendar system.
>
I'm not sure what the point is here, though?
It's the job of the application to present to the user a representation of a date that they can understand. It's the job of the programmer to interpret that unambiguously such that it can be stored and recreated -- which is the issue here. Talking about date components in the abstract as if any date can arbitrarily be reduced to a collection of components without reference to any other context (the calendar and time zone) is misleading.
mmalc
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