Adding the message halt

To interrupt the running of your code, find a place in your code where you want to gather information. Then, specify a breakpoint by adding the message halt or the expression self halt.

For example, evaluate the following code in a Workspace with the Execute command:

(OrderedCollection new)

halt;

add: 'Alix';

add: 'Sam';

add: 4;

add: (Date today);

at: 4 put: 'Cathy';

yourself.

A debugger opens, showing the error message '(ExHalt) A halt has occurred.' The top of the stack has the following messages:

[] in <optimized block>(ExceptionalEvent class)>>#initializeSystemExceptions

Signal>>#evaluate:

Signal>>#evaluateDefaultHandler:

ExceptionalEvent>>#applyDefaultHandler:

ExceptionalEvent>>#signalFor:

ExceptionalEvent>>#signalWithArguments:

ExceptionalEvent>>#signal

OrderedCollection(Object)>>#halt

UndefinedObject>>#Doit

Select OrderedCollection(Object)>>#halt in the message stack and inspect self in the list of variables. Notice that the ordered collection exists but contains no entries.