GNU Smalltalk User's Guide
4.8 When Things Go Bad
So far we've been working with examples which work the
first time. If you didn't type them in correctly, you probably
received a flood of unintelligible complaints. You
probably ignored the complaints, and typed the example
again.
When developing your own Smalltalk code, however, these
messages are the way you find out what went wrong. Because
your objects, their methods, the error printout, and your
interactive environment are all contained within the same
Smalltalk session, you can use these error messages to debug
your code using very powerful techniques.
