Ok, just give me some time

On Sat, Apr 18, 2026 at 9:48 PM Jonathan Wakely via Std-Proposals <
std-proposals_at_[hidden]> wrote:

>
>
> On Sat, 18 Apr 2026, 11:01 Giuseppe D'Angelo via Std-Proposals, <
> std-proposals_at_[hidden]> wrote:
>
>> Hello,
>>
>> On 18/04/2026 05:04, Muneem via Std-Proposals wrote:
>> > I updated my proposal:https://docs.google.com/document/d/1srd5nKI-
>> > QZy0vpUdkQoD45JyKIDWhom8/edit?
>> > usp=sharing&ouid=114869935649093915681&rtpof=true&sd=true <https://
>> > docs.google.com/document/d/1srd5nKI-QZy0vpUdkQoD45JyKIDWhom8/edit?
>> > usp=sharing&ouid=114869935649093915681&rtpof=true&sd=true>
>> > Thank you a lot to everyone for giving their feedback that led me to
>> > refine my proposal
>>
>> First and foremost: this isn't a proposal. It's just an abstract idea. A
>> proposal has to go in detail: discuss tradeoffs, provide a reference
>> implementation, tentative wording.
>>
>>
>> In 2.1 there's this claim:
>>
>> > Existing tuples cannot be optimized for runtime indexing without
>> breaking the Application Binary Interface (ABI). Furthermore, switch
>> statements are not guaranteed to be the fastest option for tuples with many
>> elements.
>>
>> Could you show some data supporting this statement?
>>
>> Do you have a prototype implementation where you add such runtime
>> `get(index)` to an existing std::tuple implementation, as well as a
>> prototype implementation of the proposed runtime_index_tuple, and show
>> that the new class brings significant performance gains (... that can't
>> otherwise be achieved without breaking std::variant's ABI)?
>>
>> > This proposal introduces a specialization for std::variant<T&...> with
>> the following properties:
>> > No Valueless State: The variant cannot be valueless by exception.
>> > Immutable Type Selection: Every std::variant<T&...> is constructed with
>> a reference to a type T that it holds for its entire lifetime.
>> > Assignment Logic: Assignment modifies the underlying value referred to
>> by the variant rather than changing the active type.
>>
>> 1) These are extraordinary claims that aren't backed by extraordinary
>> facts.
>>
>> 2) Adding support for references in std::variant deserves its own paper.
>> It's something that was there originally and then removed by P0510.
>>
>
>
> Until this idea has been implemented and tested, this whole thread is a
> waste of time.
>
> Try to implement it, then come back with a real proposal with numbers to
> prove the claims.
>
>
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