[Gbbopen-list] agenda-shell activation/obviation/retrigger puzzle

[Paul Werkowski]

Dan Corkill wrote:
> 
> You are correct in assessing that activation-predicate and
> obviation-predicate apply to whether a KS is activated or remains
> pending, and that they are one-shot (can't be undone) decisions.
> 
> The traditional "trick" in doing what you want is to use the KSA rating
> value to make the pending KSA non-executable by lowering the rating
> below the minimum-ksa-execution-rating.  The default
> minimum-ksa-execution-rating is 1 (and by convention, is rarely
> changed), so setting a KSA's rating to zero will make the KSAs
> non-executable (but still pending) until the rating is raised later on.
>  (This "trick" is one of the reasons the default minimum is 1--a nice
> convention where negative & 0 can mean non-executable.  Note that you
> can "remember" the old rating my simply negating it (to block) and
> re-negating it later (to unblock).
> 
> This approach does have the small cost of a pending-ksa queue insertion
> on each transition to/from blocked.
> 
> -- Dan

Ok, makes sense. Thanks for the info.

Paul


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