Re: Time Intervals

From: Mark Davis (markdavis34@home.com)
Date: Thu Feb 01 2001 - 22:49:39 EST


Whether processing can be simplified or not is not a particularly important
issue to the subject at hand, which is producing well-defined constructs for
time and duration (since they are definitely very flawed in 8601).

ICU does have ISO year-week support. See
http://oss.software.ibm.com/icu/apiref/class_SimpleDateFormat.html#_details

Mark
----- Original Message -----
From: "Carl W. Brown" <cbrown@xnetinc.com>
To: "Unicode List" <unicode@unicode.org>
Sent: Thursday, February 01, 2001 09:38
Subject: RE: Time Intervals

Mark,

I did not find anywhere in the discussion of time issues the notion that
since the starting point is arbitrary that processing could be simplified by
shifting the starting point to a March start. The only problem is leap
seconds which are added at the end of the calendar year. But leap seconds
are a problem anyway. Most systems usually compensate by adjusting the
starting point so that the current time is synchronized. This is adequate
for most uses. Thus the 1/1/70 epoch time does not actually match the
actual historic time but has been adjusted to compensate for the leap
seconds.

On a related subject I am writing a strftime to ICU date format conversion
routine and noticed that ICU has no week based year support. Fortunately I
don't think my client needs it.

Carl

-----Original Message-----
From: Mark Davis [mailto:markdavis34@home.com]
Sent: Thursday, January 25, 2001 9:18 PM
To: Carl W. Brown; Unicode List
Subject: Re: Time Intervals

Yes, some date calculations are easier that way. But in reference to what
are you saying this?

Mark
----- Original Message -----
From: "Carl W. Brown" <cbrown@xnetinc.com>
To: "Unicode List" <unicode@unicode.org>
Sent: Thursday, January 25, 2001 07:35
Subject: RE: Time Intervals

Mark,

Date calculations are much easier if you start on a March 1 date such as
March 1 1900. This is becase the months are 31,30,31,30,31 31,30,31,30,31
31,xx Putting February last makes leap year calculations easier.

Carl

-----Original Message-----
From: Mark Davis [mailto:markdavis34@home.com]
Sent: Monday, January 22, 2001 9:32 AM
To: Unicode List
Subject: Re: Time Intervals

This appears to have bounced the first time I sent it.

----- Original Message -----
From: "Mark Davis" <markdavis34@home.com>
To: "Unicore" <unicore@unicode.org>; "Unicode" <unicode@unicode.org>
Sent: Monday, January 22, 2001 08:04
Subject: Time Intervals

> After a request from Tex, I realized that I hadn't posted my notes on the
> issues with ISO 8601 on this list. (More exactly, issues with a previous
> version of Schema, but since ISO 8601 is not well-defined, it wasn't
> either.)
>
> The page is at http://www.macchiato.com/unicode/timeIntervals.htm
>
> Mark
>
> ----------
> http://www.macchiato.com
>



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