class, prototype, meta

Alan C. Kay alank at
Sun Mar 1 05:36:07 UTC 1998

Mike --

At 9:15 PM -0800 2/28/98, wirth at wrote:
-- snip --
>Gregor apparently published another book on MOPs by himself after "Art of
>the Metaobject Protocol", at MIT Press, titled "Open Implementations and
>Metaobject Protocols", in both hardcover (Sept 94, ISBN: 0-262-11192-6) and
>paperback (June 95, ISBN: 0-262-61103-1).  But my attempts to get a copy at
>all the usual places (MIT Press, Amazon, Stacey's in Palo Alto, and even
>the Stanford Bookstore) have failed.  How different is this book from the
>"AotMP" (which I have)?  Should I persist in trying to get a copy?

Yes, it is very useful. Try Amazon or MIT Press online.

>Gregor seems to be pursuing a new topic, "aspect oriented programming".
>Any comments on this line of research?  A quick read of the intro web pages
>didn't leave me with enough concrete understanding to assess the ideas.

I don't know the genesis of his particular interest. The idea of "aspects" (or "perspectives") was another hot topic at PARC among both the Smalltalkers and Danny Bobrow's original group that did KRL. It's possible he picked up the notion via Danny, or he could have thought of it himself.

>You said:
>...But it is really terrible if you just ban such things. That is too
>moralistic and smacks of the Wirth school of (non)programming. This is why
>well thought out metasystems should allow the good designer/programmer to
>have their cake and eat it too. The "Metaobject protocol" by Greg and
>Danny, et. al., at PARC is an inspiring further advance in what we had done
>there in the '70s, and it gives some tantalizing insights into what could
>yet be invented....
>Ouch!  How can I clear my name? :-)  Maybe I'll just have to convince you
>that Nicklaus is the "call-by-name" Wirth and I'm the "call-by-value" Wirth

Sorry, I should have said "the Bucky school of (non)programming" (that was his nickname at Stanford). Actually, I would think you would want to reverse your metaphor, since "call-by-name" is a much more powerful and useful concept than "call-by-value"......



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