[etoys-dev] Toy computers

karl ramberg karlramberg at gmail.com
Mon Oct 3 17:14:20 EDT 2011

Cool project.
It would be nice to play with a project like this :-)
I think you should play with Etoys a bit to get to know the
environment and how your electronic component
system could be added.

Etoy reference under development:

A EtoyMorph is is any morph.
You can make scripting additions on the class side that contain the
special additions the morph make.
Note that Etoys have limited number of types!
These additions must be added to Player as well.
So if your morph has a variable called 'adder' that can be read and
written you usually add a getAdder and setAdder: in the class
additions side of the morph. And you also put getAdder and setAdder:
to Player.

Etoys have a little different collection library. It uses holders,
PasteUpMorphs, that can contain quite a big variety of objects. To use
it as a programming collection you must be a little creative.

Feel free to ask if you run into issues on your way


On Mon, Oct 3, 2011 at 5:01 AM, David T. Lewis <lewis at mail.msen.com> wrote:
> Hi,
> I am a lurker on this list, but a long time Squeak participant. When I
> was a child, my parents gave me an interesting toy - a DigiComp I plastic
> mechanical computer <http://en.wikipedia.org/wiki/Digi-Comp_I>. I always
> remembered that toy, and it makes me wonder if computing machines could
> be assembled by children using objects in Etoys.
> If I wanted to assemble a simple computer, I would probably start by
> connecting some registers and an accumulator, then figure out how to make
> the bits move, like cycling the plastic clock lever on my DigiComp I.
> So the first thing I might need would be a register object that does
> arithmetic and logic operations when I push the lever.
> I don't know much about writing morphs and making them work in the Etoys
> environment, but I can write Smalltalk so I started by constructing some
> basic register building blocks. First I made a BitRegister, which is a
> simple one-bit computing element. Then I made a TwosComplementRegister,
> which uses a collection of BitRegisters to make a more useful general
> purpose register and accumulator of any size. I decided that using
> numbers to implement arithmetic would be cheating, so it's all done
> with booleans instead.
> That's as far as I have gotten this weekend, but you get the idea. If I
> could turn these register building blocks into graphical Etoys morphs,
> then figure out how to assemble them into an arithmetic-logic unit, and
> tie that together with an instruction interpreter, then pretty soon it
> might turn into something interesting and fun for learning.
> The register objects are on SqueakSource in project "Twos Complement"
> at <http://www.squeaksource.com/TwosComplement>.
> Collaborators welcome.
> Dave
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