[squeakland] Stopping infinite loops in Etoys

Bert Freudenberg bert at freudenbergs.de
Wed Feb 24 05:01:47 EST 2010

On 24.02.2010, at 07:32, Steve Thomas wrote:
> Just discovered that Cmd-. (aka <command><period>) on Macintosh stops currently running scripts and changes their state to pause. On a Windows and XO I assume its Alt Key instead of Command Key.
> (http://wiki.laptop.org/go/Etoys_Shortcuts) 
> This is very useful when kids create scripts that lock up the system (this happened to me when I was trying to teach kids how to make babies, or in more politically correct terms: trying to model lemming behavior by having the lemmings breed, but the kids got a real big kick out of me telling them their homework was to make babies, it was a real motivator and motivation trumps political correctness IMHO).  The problem was they would create a script which would make a sibling copy of the lemming object when a male and female touched, they would forget to add a pause script or move the lemmings away from each other. We had to force quit Etoys to resolve the issue and it was very frustrating for the kids.

I previously proposed having a general "pause" button in the tool bar: 
Scott had some valid objections and we did not have time to work on it anyway so it never got done. However, IMHO the general idea of a "stop all tickers" button is still valid - maybe not a general pause/resume control as I suggested in the ticket but just a big red PANIC button that pauses all ticking scripts.

If you would like to see that implemented, at least vote for it on the tracker ticket, add a comment, maybe even change its priority etc. (as usual on the tracker).

Alt-. / Command-. is really a low-level interrupt. It can even break into an infinite recursion where no mouse clicks are ever serviced. One thing we should definitely do is making the resulting dialog a bit friendlier. Its current interface is aimed at developers.

> Also another useful tip on this page is the multi-object select (Shift Click and drag around the objects you want to select). This is useful for alignment. To access alignment commands et al, click on the menu in the Halo that appears around the multiple objects.
> We should probably document both these items in the Manual, probably under "User Interface Keyboard" and possibly scripting.


- Bert -

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