[Squeakland] spiral

Shashank Date sdate at everestkc.net
Sun Dec 12 12:42:41 PST 2004

Hello Alan,

Alan Kay wrote:

> Hi --
> Generally speaking, 5th graders get along very well without a repeat 
> tile (but more and more older children are using etoys and thus we 
> will include a loop construct some time this year).

Great ! Yes, we were doing fine without the repeat tile so far, but now 
our kids (6th and 7th graders)  want to do more :-)

> But all the different kinds of loops are easy to make from two 
> scripts, one to initialize, and one to do the loops and terminate. Use 
> a variable if you are doing a "for" type loop.
> So for player foo, "For i from 1 to 100 do mumble" would be:
> foo loopInit
>     i <- 1
>     foo start script loopBody

And here we had to add:
         foo stop script loopInit

without which the clock kept ticking and the loopInit scipt kept 
executing over and over again. (There is an implicit infinite-loop on 
all the scripts).

> foo loopBody
>     Test foo's i > 100
>        Yes   foo stop script loopBody
>         No    mumble
>                 foo's i increase by 1
> This is somewhat cumbersome, but is quite clear about what it does and 
> when it does it.

Worked like a charm ! Thanks for the hint.

> It has not come up as an issue with 5th graders because they stuff 
> that we are encouraging them to do has either unbounded looping (the 
> normal case) or the looping is stopped by some test of an external 
> condition (as Phil suggested).


> Cheers,
> Alan

-- Shashank

More information about the Squeakland mailing list