Subbu,
The current slots/commands in basic category is part turtle geometry and part cartesian geometry. I recast the viewer to include only turtle geometry primitives in basic to make etoys easier for children who are yet to develop intuitive understanding of co-ordinates. Why present two systems when one is sufficient?
Even if we follow this line of thought, you would still like to keep "heading" in the basic category, yes?
Ideally, we could have easier version(s) of position vector representation in the basic category, but for various reasons (like hiding scary-looking "@" operator), we sort of substitute the vector representation of location with x and y. This has some merit: the first thing the end-user does after painting/instantiating an object is to pick it up by a mouse and move. If the viewer is opened, the x and y values in the viewer will change and give good indication that the viewer is actually a "view" on the object. (And, by typing the numbers, smart kids can tell that the relationship is bi-directional.)
In future systems, the end-user should be able to reorganize the categories for each object. This way, a teacher can set up a nicer material, for example. You have a point, but but for now, I think current affair is "ok".
In future systems, various different notation/representation of vectors should be really nice, too. What kind of notation would be good for children?
I would have liked to make "pen down false/true" to "pen down/up" but I am yet to figure out a simple way to get Boolean slots to support arbitrary strings/symbols instead of just true/false values.
Hmm, you might have to define a new DataType for it...
throwing it open for discussions,
Thank you!
-- Yoshiki