[etoys-dev] Etoys: Etoys-Richo.100.mcz

Scott Wallace scott.wallace at squeakland.org
Mon Feb 13 15:45:18 EST 2012

> What is the use case for batching pen trials ?

Here's the earliest mention I find of it in my email archive -- from an email from Dan Ingalls, May 25 2000:

> Beginning with the balloon help for that preference (it's in the 'scripting' category;  you have to open a new preferences panel after filing in the file in order to see it)...
> "batchPenTrails:
> Ignores the detailed
> movement of pens between
> display updates.  Thus
> multiple line segments
> drawn within a script may
> not be seen individually."
> This feature allows you to write scripts such as
> 	joe's x := joe's x + vx.
> 	joe's y := joe's y + vy.
> and see a smooth resulting line instead of an x-y stairstep.
> The downside is that if you happen to write
> 	joe forward: 50.
> 	joe turn: 45.
> 	joe forward: 50.
> 	joe turn: 45.
> and run that script, you will neither see 45-degree angles nor sides of length 50.  What it draws is the square formed by the lines from the beginning to the end of the script (ie a square inscribed inside the octagon that you might expect).

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