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Subject: Re: [std-proposals] The new new thing
From: connor horman (chorman64_at_[hidden])
Date: 2020-02-20 18:33:31


On Thu, Feb 20, 2020 at 19:22 Matt Hurd via Std-Proposals <
std-proposals_at_[hidden]> wrote:

> using my_typedifferent_int_t = int64_t is a little disappointing. No type
> safety by design which is excellent mostly.
>
> How about:
>
> using new qty_t = int64_t;
> using new px_t = int64_t;
>
I assume this is similar to rust’s

#[repr(transparent)]
struct qty_t(i64); // i64 = int64_t.

This doesn’t really communicate that intent, imo.
For integers, we really can do something similar in one line with:
enum class qty_t : int64_t {};
While we are technically out of luck for other types, a wrapping aggregate
struct isn’t that horrible (though potentially with an attribute that hints
it wants the abi of the wrapped field).

> auto bid = qty_t{100};
>
> auto ask = px_t{200};
>
> auto err0 = bid + ask; // does not compute
>
>
> & extensions without inheritance for reuse?
>
>
> template<typename T>
>
> struct bah_humbug_vector2 : new std::vector<T>{
>
>
> constexpr auto ssize() const noexcept ->
> std::make_signed_t<decltype(size())>{
>
> assert( size() <= std::numeric_limits<size_type>::max );
>
> return static_cast<std::make_signed_t<decltype(size())>>(size());
>
> }
>
> };
>
>
> It would simplify a lot of my life and bring some facilities to C++ other
> languages support.
>
>
> < $0.02
>
>
> --Matt.
>
>
>
>
>
> --
> Std-Proposals mailing list
> Std-Proposals_at_[hidden]
> https://lists.isocpp.org/mailman/listinfo.cgi/std-proposals
>



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