[alankay]

In the HOPL paper is some discussion of the first design for Smalltalk, that I was working on when "the bet" happened and brought Smalltalk-72 to life as the answer to "the bet" (it used a combination of Lisp and Meta II techniques to win the bet). This made it quite easy to implement, and once Dan Ingalls implemented it, we started using it.

Smalltalk-71 was never implemented (and never had its design finshed, so there is less that can be claimed about it). But, germane to this discussion, I really liked Carl Hewitt's PLANNER language, and the entire approach to "pattern directed invocation" as he called it -- this was kind of a superset of the later Prolog, and likely influenced Prolog quite a bit.

The PLANNER ideas could be used as the communications part of an object oriented language, and I thought this would be powerful in general, and also could make a big difference in what children could implement in terms of "reasoning systems" (not just imperative action systems).

For Smalltalk-72 I used a much more programmatic approach (Meta II) to recognize messages (that also allowed new syntax/languages to be defined as object protocols (to win the bet) but this was not done comprehensively enough to really use what was great about PLANNER.

There were a few subsequent attempts to combine objects with reasoning, but none of them that I'm aware of were done with end-users in mind.

I thought the subsequent ACTOR work by Carl and his colleagues produced really important theoretical results and designs, most of which we couldn't pragmatically use in the personal computing and interface work on the rather small Xerox Parc personal computers.