Help with morph and world refresh

Alan Kay Alan.Kay at
Sat Apr 5 13:21:13 UTC 2003

Why not just do this in the Etoys authoring environment?




At 2:16 PM +0200 4/5/03, Stephane Ducasse wrote:
>Hi bob
>I want to implement a robot a la Karel that novices can program.
>Using the step mechanism for that is not clear for me because the 
>idea is that kids
>can define any kind of method in terms of the simple elementary one. 
>So I have everything working except this problem with the refresh of 
>the world.
>I have to  think about your solution with the calculatePositionAt:
>On Saturday, April 5, 2003, at 01:45 PM, Bob Arning wrote:
>>On Sat, 5 Apr 2003 10:37:01 +0200 Stephane Ducasse 
>><ducasse at> wrote:
>>>I have the impression that this is a really bad practice to explicitly
>>>wait for the refresh but I do not know how to do it in a better way.
>>>Have you suggestion to fix my problem?
>>It sounds as if you really want to slow the robot down to some sort 
>>of "realistic" rate of progress so that you can actually see it 
>>doing stuff. The morphic approach would be to use a #step method...
>>	position _ self calculatePositionAt: Time millisecondClockValue.
>>	self goTo: position.
>>	self canPick ifTrue: [self pick].
>>and make this run as often as possible...
>>	^1
>Prof. Dr. Stéphane DUCASSE
>  "if you knew today was your last day on earth, what would you do 
>different? ...  especially if,
>  by doing something different, today might not be your last day on 
>earth" Calvin&Hobbes
>"The best way to predict the future is to invent it..." Alan Kay.
>Open Source Smalltalks:, 
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