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Re: proposed new definition of preemption

From: David Junger <tffy@free.fr>
Date: Tue, 26 Feb 2013 10:17:56 +0100
To: "VBWG Public (www-voice@w3.org)" <www-voice@w3.org>
Message-Id: <B29BE075-A719-424F-ABA2-42F4DB1FF7E4@free.fr>
Le 25 feb 2013 à 16:53, Jim Barnett a écrit :

First, I think we should preempt in transition order, not document order (i.e. a transition should be preempted by transitions that are selected before it, not witten before it). If we use document order, then we'll end up with <state>s and <transition>s mixed in complex states to achieve a precise result, very hard to read or visualize.
> 3.       Is it a good idea to get rid of the word “preemption”?  (the selectTransitions functions have to be modified to call removeConflictingTransitions instead of filterPreempted, but the argument to the functions and the return values are the same.  hasIntersection() und union() are defined in the list of functions/procedures at the top of the algorithm)

I don't mind the word. I just hoped we could find an elegant solution that made it unnecessary.

> 4.       Is there a better way to do this?

It seems that targeted transitions will always conflict if one's source state is a descendant of the other's and that those cases are precisely the cases that trip the source state approach. Is that correct? I don't think that would be a "better" way to explain it in the spec but if it is equivalent then I like it better for my implementation (in which I don't want to compile exit sets in advance, for example).

Received on Tuesday, 26 February 2013 09:18:30 UTC

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