On Thu, Aug 30, 2012 at 5:36 AM, Andrzej Krzemienski <akrzemi1@gmail.com> wrote:
Hi, I have just realized that there is an interesting interaction between "noexcept" and Contract Programming framework. Not only Lorenzo's library, but even if contracts were a language feature. N3248 ("noexcept prevents library validation", http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2011/n3248.pdf) recommends that functions with any preconditions should not be declared noexcept(true) in case someone wants to report precondition failures via exceptions. If preconditions become part of declaration syntax, declaring both precondition and noexcept(true) could (and should?) be recognized as compile-time error.
But now also invariants and postconditions come into play: if a function declares a postcondition, or our class defines an invariant, should we be allowed to declare our function noexcept? What if someone wants to report an invariant or postcondition failure via special exception? (I do not have a good answer for it.)
I see... I think it should be OK however if you don't report contract failures using exceptions (but you just let the program terminate in case of a contract failure). Ideally, if you start throwing from the contracts and you also use noexcept, the lib will give you a compile-time error. I'll note this issue and I'll explore it fully when I start supporting C++11. Thanks, --Lorenzo