Peter Levart peter.levart at
Thu Jan 28 09:12:12 UTC 2016

On 01/28/2016 02:50 AM, John Rose wrote:
> On Jan 22, 2016, at 1:03 AM, Peter Levart <peter.levart at 
> <mailto:peter.levart at>> wrote:
>> a symmetric configuration where each nest-mate lists all nest-mates 
>> in a single Nest attribute
> That uses storage quadratic in the number of nestmates.  A big price 
> for beauty!
> Better to go with transitive closure on a graph (linear storage).
> That takes us straight to a simple star graph, which is why we have a 
> NestTop.
> Fun fact:  If the nestmate relation is an equivalence relation, any 
> class can
> be the top.  This means that a compiler could put the bulky nestmate list
> into a small synthetic class, at least in principle.  (Might look 
> surprising
> under reflection.)
> — John

I was just concerned that a decision to store the information centrally 
in one class would necessitate loading of the top class even when the 
access was checked between two non-top classes and that such loading 
could have an undesirable side-effect to the execution semantics. If the 
top-class attribute extraction can be performed without visible 
site-effects then keeping the information in one place is certainly 
preferable and simpler.

Regards, Peter

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