In his interpretation exceptions were just a little short of being fatal errors. They were almost fatal errors but with an optional escape hatch. But I agree all these distinctions are vague and do not seem to be fundamental differences.
Exceptions are a side effect of nice syntax. When we write
a = b + c
in a modern language quite a lot can happen behind the scenes. Yet the form implies 'a' will always be a sum of 'b' and 'c' whatever this means. There is no notion of 'a' not being a sum. So it seems there are two ways: either we provide a separate error handling mechanism (exceptions) that stops the execution and leaves 'a' undefined or we somehow turn 'a' into either a sum of 'b' and 'c' or an error (sum types).
Exceptions are a side effect of nice syntax. When we write
in a modern language quite a lot can happen behind the scenes. Yet the form implies 'a' will always be a sum of 'b' and 'c' whatever this means. There is no notion of 'a' not being a sum. So it seems there are two ways: either we provide a separate error handling mechanism (exceptions) that stops the execution and leaves 'a' undefined or we somehow turn 'a' into either a sum of 'b' and 'c' or an error (sum types).