Some Practical Issues

Syntax errors

The debugger

Practical Issues

Some practical issues: syntax errors and the debugger.

If you make a mistake, there are two likely outcomes.

The first is that you will have entered a syntactically invalid Self expression. This will cause a red error notifier to appear. The error will fly off the screen after a short time.

The second is that you entered a syntactically valid expression, but this led to a runtime error, such as sending an inappropriate message. This will cause a debugger to appear (they are green, in a puerile attempt to look friendly). Don't panic!

You have several options. One is to read the message in the debugger, then dismiss or abort it. Another is to examine the stack of the process by using the stack expander. You can then observe what was happening at the time of the failure by opening the method editors on each stack frame, and you can even fix the problem there if you so desire.