Alias and variable template versions of Boost.Geometry traits

[awulkiew]

What do you think about adding alias and variable templates to the library?

Besides being shorter than the original traits this would also allow us to avoid using typename keyword, so:

typename point_type<T>::type                      -> point_t<T>
typename select_calculation_type<G1, G2, T>::type -> select_calculation_t<G1, G2, T>
dimension<T>::value                               -> dimension_v<T>
is_multi<T>::value                                -> is_multi_v<T>
etc.

I haven't looked into this deeply but maybe we could unify calculation_type, select_calculation_type and select_calculation_type_alt as well?

[barendgehrels]

👍 yes, this is quite common now, and shorter. I like it, and also unifying calculation types.
It's all used throughout the code - changing it will be quite some work...