>Can someone please help me to understand the debugger walkback
>in the following attached zipped pictures?

I hope I'm just not stating the obvious here but...

A **System Error Handling Failed** occurs when an error occurs WHILE Squeak is trying to show that another (previous) error occurred.

>From the 0000 picture it looks like Squeak was trying to open a Debugger to show one error and while it was doing that another error occurred.

The second error looks like it occurred because something went wrong in 'Color setRed:green:blue:'.  It says a message was sent to a Fraction that Fractions don't understand.

Looking at  'Color setRed:green:blue:' my guess would be that message was bitAnd:

Only Integers understand bitAnd:

But bitAnd: was being sent to the result of 'rounded' which should ALWAYS be an Integer.

So I'm kind of stumped.  What we need to know is what the arguments were to these methods.  Unfortunately the code that draws that '**System Error Handling Failed** ' thingy doesn't show the arguments, just the message selectors.

My suggestion:  Modify the code that displays that '** System Error Handling Failed **' thingy so it shows the class name of each of the arguments (this should have been done YEARS ago).

Attached is the change to this method.  It isn't the prettiest thing in the word but it will do the job.  File it in. Then start the image again.  And cause the problem to happen again.  Hopefully now you will be able to see the arguments to these methods that caused the problem (in the '** System Error Handling Failed **' thingy).

If it's possible to send 'rounded' to a Number and get back a Fraction, that is a VERY SERIOUS bug in Squeak.

If you can find and fix this bug then you can try running the system again and hopefully the Debugger will appear properly to show you whatever the FIRST error was.

Sheesh!!!  Debugging is such an art form, even with the excellent debuggers of Smalltalk.

Let me know if you find the problem.

Carl Watts
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