Lego RCX-morph and SQLego stability

Ned Konz ned at bike-nomad.com
Wed Aug 14 15:00:17 UTC 2002


On Tuesday 13 August 2002 09:45 pm, Edmund Ronald wrote:
> Hi Ned and others interested in Lego + Squeak -
>
>  I cannot manage to load in Ned's  RCXMorph file, with or without
> Alexandre's classes loaded into a 3.2 Squeak. I was interested in
> Ned's code as Alexandre's stuff seems to work *sometimes* and often
> puts up an error notifier.

More info required:

What error notifier? What's the stack? What's the error?

Why can't you load my RCXMorph stuff? What happens when you try?

> Anyway, my questions are
> 1. Is there a *stable* version of the comms routines for the RCX ?
> How do I debug the error notifiers I get intermittently ?

Get into the debugger and look around. Examine variables, copy stacks, 
try to figure out what's happening.

> 2. How do I figure out the loading problems for RCXMorph ? I am a
> newbie albeit a middle-aged one :)

Get into the debugger and look around. The debugger is your friend.

> 3. What is the state of play on Lego and Squeak ? Shall we form a
> SIG ? :)

I don't know. Perhaps Alexandre has done more. I wasn't too interested 
in local mode (that is, Squeak controlling RCX directly); I would 
rather see an RCX programming environment that sends programs to the 
RCX. But I don't have time to do it, considering I have to figure out 
how to pay rent.

> 4. How does one work around error notifiers at run-time -
> ie catch the notifier with a different process and fail gracefully
> - without having to rewrite complex existing code like the RCX 
> comms stuff ?

Wrap the calls in an exception handler. See BlockClosure and its 
execution methods. There's on:do: and ensure: etc.; you can (among 
other things) retry the failing block.

I uploaded a fixes file to
http://minnow.cc.gatech.edu/squeak/2412

You might try loading it after the RCX change set.

-- 
Ned Konz
http://bike-nomad.com
GPG key ID: BEEA7EFE




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