AMDG Lorenzo Caminiti wrote:
struct z { static int counter; int number;
CONTRACT_CLASS( (z) (static) (invariant) ({ // Static class invariants (no object here). CONTRACT_ASSERT( counter >= 0 ); }) (invariant) ({ // Non-static class invariants (`this` present). CONTRACT_ASSERT( number <= counter ); }) )
... };
Why does n1962 not support static class invariants?
Would it be possible to have something like CONTRACT_INVARIANT { // arbitrary code }; CONTRACT_STATIC_INVARIANT { // arbitrary code }; To me at least, this would look cleaner than having all the parentheses.
Finally, the use of CONTRACT_OLDOF(variable) requires programmers to explicitly indicate that the variable type is copyable using (copyable) in the function signature adding syntactic overhead.
This kind of worries me. Do you always make a copy whether it's needed or not when the object is marked as copiable?
12) CONSTANT-CORRECTNESS Block invariants are constant-correct in n1962 but not in Boost.Contract. (Class invariants and pre/postconditions are constant-correct in both n1962 and Boost.Contract.)
Unfortunately, I do not know how to enforce constant-correctness of block invariants (and also of loop variants) for Boost.Contract because I cannot inject const within a code block:
class z { void f() { const { // Can't do this... so f() is not const and block invariants are also not const in this context... ... // block invariant here } } };
This is a limitation of Boost.Contract.
You can pull the code block out into a separate function. In Christ, Steven Watanabe