dan@pokey.UUCP (10/07/85)
For anyone who is used to reading the horror stories in Software Engineering News, the idea of bug-free large programs is a bit hard to grapple with. Large programs are so complex, and have so many states, that exhaustive testing would take hundreds or thousands of years. Even in the unlikely event that you do have a mechanical proof system, that system is vulnerable to the input and output predicates for a given code fragment. The important thing about Ada exceptions is that they include the ability to trap constraint and range violations like the one which would supposedly appear on the pilot's display. Proper coding standards will enforce the creation of programs in which these (unlikely but possible) errors would be trapped and dealt with in an orderly way. Sure beats the heck out a C program that goes off the end of an array and fires your ejection seat . . . -- Dan