RE: MIA, Ask an Expert: control turtle with keys

["Alain Tougas" <alain@xxxxxxx>]

Hi,

I won't give you the exact code, but here's the general technique.

Reading the keyboard involves
1. detecting a key being pressed
2. checking its ASCII value (each key has one)

To find out what the ASCII values are, type this in the command center
repeat 4 [show ascii readchar]
click on the page (important for readchar to work)
then hit the four arrow keys in order
Note the four values that you got in the Ccenter

Now the procedure:

to drive
if key? [react ascii readchar]
end

to react :thiskey
if :thiskey = ?? [whatever]
if :thiskey = ?? [whatever]
if :thiskey = ?? [whatever]
if :thiskey = ?? [whatever]
end

You must execute "drive" forever (forever command, button or clickable
turtle - buttons and clickable turtles are better because they "force" you
to click on the page, which is mandatory for readchar to work)

Ciao,

Alain

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Subject: MIA, Ask an Expert: control turtle with keys

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from: Scott <Smobley@xxxxxxxxxxxxxxxxxxxxx>
date: Thu Mar  1 21:41:56 2007
platform: Mac OS10
version: MicroWorlds Ex

How do I program my project so that I can control a turtle
with the keyboard (arrow keys)?