Tim,

> There is also the cost of a test everytime you might possibly find an
> indirector. I'm sure I've read about some analysis of this sort of cost
> somewhere - could it have been in Ungar's PhD thesis? Anybody know? Eliot, you
> still have my copy, can you look and see :-)
> 
> Don't forget that the check would not only be during message sends, but
> anywhere that an oop is 'dereferenced' which is in quite a lot of places.

Can you explain what you understand by 'dereferencing'? From my (naive)
point of view Lex's description was that of a proxy and I would think that
you just have to catch the cases where the normal lookup does not work
(e.g., special sends like #== and #class). The extra indirection will cost
something in the long term but this may be acceptable for faster #become:
operations in some cases.

  Andreas
-- 
Linear algebra is your friend - Trigonometry is your enemy.
+===== Andreas Raab ============= (raab at isg.cs.uni-magdeburg.de) =====+
I Department of Simulation and Graphics      Phone: +49 391 671 8065  I
I University of Magdeburg, Germany           Fax:   +49 391 671 1164  I
+=============< http://isgwww.cs.uni-magdeburg.de/~raab >=============+