Re[2]: Optional attributes



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From: Joaquin Miller (jm-miller-at@sbcglobal.net)
Date: Wed 19 May 2004 - 02:16:11 BST


Hi, John.  Your distinction seems real simple to me, too.

The distinction about slots does not, i agree, help with your two 
cases.  Certainly a model should be able to cleanly distinguish your two 
cases.


John Daniels wrote:
>Hi Joaquin,
>
> > We are already distinguishing between the absence of a slot and an empty
> > slot, which is good.
>
>I like clear distinctions, but I'm not convinced this distinction is helping.
>
>All I'm trying to do is make sure there's a simple way to distinguish two 
>cases:
>
>1) when I want to say "every X must have a valid value for its attribute 
>p" (and I don't count "null" - whatever it means - as a valid value) and
>
>2) when I want to say "it's fine to have an X without having a value for 
>its p attribute".
>
>Pretty simple stuff (I thought).
>
>--John

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