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From: bgowing@cs.tcd.ie (Brendan Gowing)
Subject: Re: a cute hack -- delegation after doesNotUnderstand 
Message-ID: <1994Sep16.092153.9588@cs.tcd.ie>
Organization: Computer Science, Trinity College Dublin
References: <HULTQUIS.94Sep15140936@wk206.nas.nasa.gov>
Date: Fri, 16 Sep 1994 09:21:53 GMT
Lines: 26

In <HULTQUIS.94Sep15140936@wk206.nas.nasa.gov> hultquis@nas.nasa.gov (Jeff P. M. Hultquist) writes:
>A friend (Eric Raible, raible@nas.nasa.gov) and I have
...
>We recently changed the method for doesNotUnderstand so
>that, before calling the debugger, it first checks if the
>receiving instance can provide us with one or more
>"delegate instances" which should receive the original
>method in its place.  If a delegate *is* provided, the
>system sends the original message to that object and the
>execution continues unimpeded.
...
>--
>Jeff Hultquist                         hultquis@nas.nasa.gov
>NASA - Ames Research Center                   (415) 604-4970

This was also how the Actalk system was implemented in Smalltalk.
See: J.P. Briot, `Actalk: a Testbed for Classifying and Designing
Actor Languages in the Smalltalk-80 Environment', ECOOP '89.

-BG

-- 
Brendan Gowing      Distributed Systems Group, Dept.of Computer Science, 
----///--------  ---------- Trinity College, Dublin 2, Ireland. ----------
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