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Re: limits of the generic

• To: "Jeff Greif" <jgreif@a...>
• Subject: Re: limits of the generic
• From: Jeni Tennison <jeni@j...>
• Date: Sun, 29 Sep 2002 19:55:41 +0100
• Cc: "John Cowan" <jcowan@r...>, xml-dev@l...
• In-reply-to: <013901c267e6$fbd22ef0$6400a8c0@JMG>
• Organization: Jeni Tennison Consulting Ltd
• References: <200209282248.SAA07986@m...><170201240678.20020929000004@j...><013901c267e6$fbd22ef0$6400a8c0@JMG>
• Reply-to: Jeni Tennison <jeni@j...>

Hi Jeff,

> Another astonishment is that the algorithm described makes P1Y1D >
> P365D indeterminate, even though in our naive understanding, even
> including the idea of leap year, a year and a day is always at least
> 366 days.

I realise that I wasn't clear in my earlier mails about this, but I
was only suggesting comparing durations by adding them both to a
particular date and comparing the results when the result of comparing
the durations directly is undefined.

Your example of P1Y1D > P365D isn't undefined, however, as I
understand it. P1Y is between 365 and 366 days. P1Y1D is therefore
between 366 and 367 days. P1Y1D therefore *must* be more than P365D.

On the other hand, P1Y1D > P366D, for example, is undefined if you
just compare the durations, because P1Y1D *could* be more than P366D.
At that point, *one way* of resolving it would be to add them both to
today's date (or another date of your choosing) and comparing the
resulting dates.
    
Cheers,

Jeni

---
Jeni Tennison
http://www.jenitennison.com/

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    • From: "Jeff Greif" <jgreif@a...>

• References:
  • Re: limits of the generic
    • From: John Cowan <jcowan@r...>
  • Re: limits of the generic
    • From: Jeni Tennison <jeni@j...>
  • Re: limits of the generic
    • From: "Jeff Greif" <jgreif@a...>

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