Why? What operations can you only do on a 'native' type that could not be
done on a "user defined type that tries to act like a fundamental type"?

// Robin

On Sun, Apr 13, 2025, 17:54 Jason McKesson via Std-Proposals <
std-proposals_at_[hidden]> wrote:

> On Sun, Apr 13, 2025 at 7:26 AM Ivan Matek via Std-Proposals
> <std-proposals_at_[hidden]> wrote:
> >
> > May I ask your opinion why std:: and your concepts are basically a fancy
> type lists and not something more abstract?
>
> Because sometimes, you really want to deal with a fundamental type,
> not a user-defined one that tries to act like a fundamental type.
>
> > For example for std::floating_point I would expect certain operations
> like construction addition, division work “as expected” so that any 3rd
> party type is matched.
> > I presume the issue is agreeing what a “as expected” is so std:: picked
> easier type list approach.
> >
> > On Sat, 12 Apr 2025 at 19:08, Howard Hinnant via Std-Proposals <
> std-proposals_at_[hidden]> wrote:
> >>
> >> Ancedote:
> >>
> >> std::integral recently fell out of favor with me and I wrote my own
> concept that better suited my needs:
> >>
> >> https://github.com/HowardHinnant/bbi/blob/master/bbi.h#L176-L191
> >>
> >> StandardSignedInteger
> >> StandardUnsignedInteger
> >> StandardInteger
> >>
> >> The difference here is that my concepts exclue bool and the character
> types. This distinction was at best not clear in C++11, and not modeled by
> the type_traits introduced then. For my work today, it is important to not
> include bool and the character types as “integral types” as their semantics
> are not consistent with the representaiton of integral numbers.
> >>
> >> I mention this ancedote as a word of caution for building further
> concepts on top of type_traits. type_traits was a good model of the type
> system when they were introduced, but may not be today, 15 years later.
> >>
> >> Howard
> >>
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> >
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