Re: structured programming of automata with behavior trees

Hi Yoshiki,

You should be able to download the latest MCZ file from Squeaksource using your web browser and drop that file into SqueakJS to install it.

Best,
Christoph


________________________________
Von: Yoshiki Ohshima via Squeak-dev <[email protected]>
Gesendet: Dienstag, Juli 14, 2026 12:06:06 AM
An: The general-purpose Squeak developers list <[email protected]>
Cc: Yoshiki Ohshima <[email protected]>
Betreff: [squeak-dev] Re: structured programming of automata with behavior trees



On Mon, Jul 13, 2026 at 2:20 PM Lauren Pullen <[email protected]<mailto:[email protected]>> wrote:
Hi Yoshiki,

On 7/13/26 10:37, Yoshiki Ohshima via Squeak-dev wrote:
> Sounds cool.
>
> Is there a way to check it out with Squeak JS?

If Squeak JS can use monticello, it and *Variable are at
<www.squeaksource.com/Cephei<http://www.squeaksource.com/Cephei>>.  I don't see why it shouldn't work.

Well, I asked because my simple-minded attempt did not work. It appears that the NetNameResolver primitives are failing in Squeak JS (obviously, I guess. Monticello needs to be adapted to Squeak JS). I just wanted to check it out without downloading things to my local disk initially.

> I had a colleague (a long time game developer) who implemented the
> behavior tree on top of Croquet JS. It worked well for the purpose. I
> kind of liked a more general and meta solution, and later created a
> Functional Reactive Programming based system called Renkon. Croquet and
> Renkon use explicit logical time. Your Behavior Tree implementation
> probably shares the property of "at a logical time t, a node has at most
> one value", or "a node is evaluated at most once at an evaluation
> cycle".

Nice catch.  I'd not heard of functional reactive programming (or
reactive programming, for that matter) until just now.  It seems my
source materials predate the term.  Seems I have some studying to do.

My implementation uses the latter property, where a part of the tree is
evaluated at most once per tick.  I went with 3-valued logic so you
wouldn't need to use a looping DECORATOR to break the illusion that
you're working with 1 time unit per tick:.

> I am getting to like this property more and more nowadays.
Me too.  It's greatly simplified some of the things I wanted the game to
do, and I've had luck using it as a replacement to the dependency protocol.
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--
-- Yoshiki

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