johelegp / proposals Goto Github PK

Consider defining a weakly_regular concept that removes the requirement of default construction. With this:

template<typename T>
concept number = enable_number_v<T> && weakly_regular<T>;

5.3 (3) states:

In code, it would look like a trailing requires scalar_number<decltype(x * x)>. That doesn’t
scale to mixed expressions with more operations.

It could also be nicer with:

scalar_number auto square_magnitude() { return x * x + y * y; }

right?

I think there are many benefits to making the concepts library a separate product from mp-units:

1. You use a standard_case for concepts, which is inconsistent with the mp-units practices 😜
2. It is your independent hard work, so having this in a separate repository would increase your visibility
3. It would be easier for other libraries (safe numerics, linear algebra, ...) to reuse those concepts and provide feedback if it is not embedded as a part of mp-units.

The above of course assumes that the library would be available in the Complier Explorer (single header libraries don't need any special support) and Conan.

5.3.(6) has a typo in std::common_width.

vector_scalar is a really confusing name especially with 5.2.(4) in mind. Maybe vector_space_scalar or scalar_for_vector_space could be better names? Also, in case a rename of vector_space to linear_space is requested, this refactoring makes the final type read better as well.