If you're just checking MPL assertions, then presumably there's a predicate that can be evaluated without throwing. Why not just feed those predicates' results to regular runtime assertions?
Thank you for considering my proposal. You are correct in that my code has
predicates, and I do want to ship my library with these predicates evaluated by a static assert, so that uses who incorrectly use the library, receive a compile error. This library has a thorough set of unit tests, demonstrating the proper usage of the library with expected results. However, I cannot write any unit tests for regression purposes, which would validate that a false predicate result will block compilation, because of course, that unit test would not compile. When I develop code with static asserts, I generally write a number of unit tests, prove that they do not compile, and then comment them out. There is no automated regression testing. There must be other solutions to this problem I am not aware of. I considered two solutions which both basically apply the FTSE. First, the proposal I submitted allows the library author to place BOOST_MPL_ASSERT_* macros directly in the library, but then conditionally alters these macros to generate the desired run-time error in a unit test environment. The second solution would involve the library author calling a new macro/function/etc which would conditionally call the corresponding BOOST_MPL_ASSERT_* macro, or instead generate a run-time error. The second solution increases the surface area static asserts, so I favored the first solution. Doesn't seem like we need a new tool. The very point of
BOOST_MPL_ASSERT_* is to catch errors at compile time. If you want something else, there are plenty of appropriate choices.
If something already exists which meets my stated requirements above, I would greatly appreciate a pointer in the right direction. I hope I have more clearly communicated which my proposal is trying to achieve.
Thank you (really), :) Ben Robinson, Ph.D.
-- Dave Abrahams BoostPro Computing http://www.boostpro.com