Alan Kay wrote:
>
> This is pretty much how Playground (the kids' programming system we
> made (mainly Scott Wallace starting with a framework built by Jay
> Fenton) for the Vivarium project) worked as well -- though I'm sure
> it wasn't as clean as Ken's stuff (this is why I'm trying to convince
> him to put some of his ideas into Squeak).
>
> Playground was kind of a generalized event-driven system that had
> objects which were kind of like a collection of generalized
> spreadsheet cells, completely concurrent, etc.
>       This gave the kids state of objects to look at, but not
> call/return. Every value was a thread.
>

I just reread (for the third time in 12 years) the OOPSLA89 paper on
Playground.

http://portal.acm.org/citation.cfm?id=74891&coll=portal&dl=ACM&CFID=292547&C
FTOKEN=54781325

It is full of good ideas but AFAIK the ability of objects to communicate was
very impoverished. It seems they mostly interacted via the Playfield - a
planar surface where objects live. This is great for some purposes but is
too limitted in my mind. Objects could also signal events and others could
sense those events but it didn't seem as if this was a general message
passing facility. (The paper provides too few details on event signalling to
really see how general it was.)  Also it didn't seem to support strong
encapsulation - an object could inspect the internals of other objects.

What I want is a Playground-like system with real message sending,
encapsulation, and removal of the limitation to only graphical objects.

Best,

-ken kahn ( www.toontalk.com )