Re: type traits

From: Peter Dimov (pdimov_at_[hidden])
Date: 2024-02-05 10:57:46

John Maddock wrote:
> If anyone would like to comment on the other issues g.peterhoff has raised,
> second opinions are always most welcome:
> 
> https://github.com/boostorg/type_traits/issues/185
> https://github.com/boostorg/type_traits/issues/186
> https://github.com/boostorg/type_traits/issues/187
> https://github.com/boostorg/type_traits/issues/188
> https://github.com/boostorg/type_traits/issues/189
> https://github.com/boostorg/type_traits/issues/190
> https://github.com/boostorg/type_traits/issues/191
> https://github.com/boostorg/type_traits/issues/192
> https://github.com/boostorg/type_traits/issues/193
> https://github.com/boostorg/type_traits/issues/194

Since integral types are actually a compound category in the standard,

"The character types, bool, the signed and unsigned integer types,
and cv-qualified versions ([basic.type.qualifier]) thereof, are collectively
termed integral types."

I think there is justification for providing the separate categories for
signed integer (https://eel.is/c++draft/basic.fundamental#1), unsigned
integer (https://eel.is/c++draft/basic.fundamental#2), character
(https://eel.is/c++draft/basic.fundamental#11) and, for completeness,
bool.

There exist uses for each of the above categories. E.g. countl_zero
requires an unsigned integer type; Endian requires "an integral type
that is not bool"; and functions that want to take C strings need to be
constrained on a character type.