Instances of ExceptionalEvent can have a default handler block that is run if the exception occurs outside of a when:do expression.
| anException |
(anException := ExAll newChild)
defaultHandler: [:signal |
self error: 'The exception was not expected at this time.'].
anException signal.
If desired, the default handler block can be run from inside of a handler block by sending handlesByDefault to the handler's signal argument.