Re: [boost] [Safe Numerics] Review

Subject: Re: [boost] [Safe Numerics] Review
From: John McFarlane (john_at_[hidden])
Date: 2017-03-12 19:25:31

On Sun, Mar 12, 2017 at 12:11 PM John Maddock via Boost <
boost_at_[hidden]> wrote:

>
> BTW my experience with both constexpr and noexcept is that it's simply
> not enough to test at runtime, you have to contrive compile time tests
> as well, otherwise I can absolutely guarantee things will not work as
> you expect - trust me I've been there, done that, got the t-shirt!
>
> What that means in practice - and you're not going to like this - is
> that every runtime test has to have a compile time / constexpr
> counterpart, things that generate valid "safe" values should compile in
> a constexpr context (and yes the value needs checking to, again at
> compile time), while things that would throw at runtime, would be
> compile-fails.  It's a heck of a lot of tests - you might want to write
> a short program to spew out the files (the expected compile things can
> all go in one file, but expected failures each need their own test case
> cpp file).
>
> HTH, John.
>

I understand that not all tests can be compile-time. But for the ones that
can, why does there need to be an equivalent run-time test? I've found that
many/most tests of literal types can be conducted at compile time. Am I not
testing my `constexpr` functions adequately?