Strange interaction between futures and failed futures

[Denys Duchier]

pvr at info.ucl.ac.be (Peter Van Roy) writes:

> As we already discussed before, the current implementation of
> futures is buggy.

Ah, come Peter: it is not _buggy_ per se.  It can only be so with
respect to some specific formal semantics which it was never given.
Instead of throwing claims of bugginess or non-bugginess, time would
be better spent charting out the possible semantics and deciding which
one(s) we'd rather have.

> The MakeFut definition you give above is not just quasi-correct, it
> is in fact correct

Well, that was the non-requesting version; so it is `correct' only if
we decide that the semantics of futures should not provide the
requesting capability.

> How about for debugging: to observe values without changing them.

Debugging is indeed important, but it's an entirely different can of
worms.  I was wondering about the desirability from an application
programming point of view.

Cheers,

-- 
Dr. Denys Duchier			Denys.Duchier at ps.uni-sb.de
Forschungsbereich Programmiersysteme	(Programming Systems Lab)
Universitaet des Saarlandes, Geb. 45	http://www.ps.uni-sb.de/~duchier
Postfach 15 11 50			Phone: +49 681 302 5618
66041 Saarbruecken, Germany		Fax:   +49 681 302 5615
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