Re: [Boost-users] [boost] [review][constrained_value] Review of Constrained Value Library begins today

on Sat Dec 20 2008, Mika Heiskanen wrote:

David Abrahams wrote:

...

Exceptions should almost never be used in response to broken invariants.

Pardon my ignorance, but how come? The constraints I have to validate usually concern broken user input

That's not a broken invariant. A broken invariant means your program is broken.

via the command line or a query string. How should I deal with them if not with exceptions? Or to be more precise, why should I not use constrained types for validating user input if it saves me a lot of if-statements in the long run?

I would never argue that you shouldn't do that. -- Dave Abrahams BoostPro Computing http://www.boostpro.com