Scratch

Hello staudi,
I am not an expert on this topic but I know some things. I can help you on the broadcast problem but not the "when [space] key pressed" block.

Lets say you have three scripts:

Script 1:

when green flag clicked
  forever
    broadcast [step]
  end forever
end script

Script 2:

when I receive [step]
  change [number1] by (1)
end script

Script 3:

when I receive [step]
  change [number2] by (1)
  set [equal?] to <number1 = number2>
end script

If you start the program you will see that the variable "equal?" always is "true." This is because both the scripts have executed before "equal?" was updated. However, if you move the line "set [equal?] to <number1 = number2>" to script 2 you will see that "equal?" always is "false." This is because script 3 has not executed yet therefore causing the variables to be unequal.

Hope this helps! 

P.S. I'm not much of a speech maker, so please tell me if you do not understand something. ;D

Last edited by MathWizz (2010-03-14 15:23:34)

Hey guyz, thank you so much for your quick answers!

@MathWizz:
In fact, my English isn't really good and I am glad, that you have understood me  . Yes, I had something like this in mind. Thanks for testing it! This shows, that Scratch supports no multicore-processing, only a pseudo-parallelism. But when I take 2 actors for the race, let's say the cat (scratch) and any other, the cat always starts first (is Script 2 in your example). Shouldn't this happen randomly? I hope you undestand why this confuses me.

@sparks:
I just try to figure out, if Scratch can be useful to teach concepts of parellel-processing in school. That's why I want to know how Scratch deals with that and something about the way it is implemented. 
Yes it's strange. Unfortunately, the way with the "forever-loop" is much more quicker. Therefore, the pupils don't want to use the blocks that are meant to be used in this way.
The 4-key support is interesting! But what do you mean with open and closed? You mean up and down?

greetz, staudi