LOGO-L> Re: MicroWorlds Code Conversion

[JENEVOLD@aol.com]

Julie Clune writes:

<< 
 I would love to try out your Fractal tree, but I can't work out how I
 can  MicroWorldise your Fractal Tree.  What do I do with define?  Do I
 need it?  I don't need for it to stay in a one-liner form.  I would just
 like to see it work.
>>

"define" is used to define a procedure. You can use "to" instead.
(In MicroWorlds, click the "to" button.)

For example, this:
define "square [[side] [fd :side rt 90]]

is the same as this:
to square :side
fd :side rt 90
end

The difference is that "define" can be used as a command
within a Logo program, whereas "to" requires you to use the
editor. For the one-liner contest, you can use "define" to
define a procedure and run it, all on the same line.

Fractal Tree:
define "t [[x] [if :x > 1 [t :x*.6 rt 60 t :x*.6 fd :x]]] t 200

is the same as defining this procedure:
to t :x
if :x > 1 [t :x*.6 rt 60 t :x*.6 fd :x]
end

and then running the procedure:
t 200

(Notice that "t" runs itself (twice). It is "recursive".)

<<
 Also, what does reset do?  Is there an alternative command in MW I could
 use, or can I do without it?
>>

You do not need "reset". I typically make a procedure named
"reset" to reset everything which I have been messing with.
At a minimum, "reset" means go home and clear the screen.
Also it may show or hide the turtle, put the pen down, reset the
pen size and color, reset the background color, etc.

- Keith Enevoldsen

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