Sorry, I was not aware that `name_of` was removed from P2296. The point
I've made regarding name injection still stands, but it can wait post
C++26.

Le mar. 24 déc. 2024 à 12:47, Jean-Baptiste Vallon Hoarau <
jeanbaptiste.vallon_at_[hidden]> a écrit :

> Hi everyone,
>
> I'd like to have a discussion about being able to inject a name in a
> postfix injection and having a type for names that is not `string_view`
> (ideally I would have asked for feedback on those ideas in Wroclaw but I
> was not there).
>
> I've talked about the benefits in P3435, but I think the most
> important one is the following :
>
> It enables a simple and efficient implementation of tuple/variant get.
> Given a member data with some members `m0...mN`, `get` becomes
> `return data.[: cat("m", N) :]`
> This is a string concatenation and a single lookup in a hashtable. Compare
> this to what P2296 is doing : we're walking the entire fields range for
> each get (quadratic complexity) and constructing a whole vector to pick
> just one element.
> You could argue that this could be fixed by having a
> `nth_nonstatic_data_member_of` function, but not quite : at least in Clang,
> the underlying range containing the fields is a filtered linked list, that
> we have to traverse each time, which gives us quadratic complexity.
>
> Arguably, this does not requires a type for names. A postfix injection
> could be accepting a range of char. However a range of char is a really
> poor representation choice for operator names and conversion names.
>
> Also, a builtin type for name could be passed as template arguments just
> like `std::meta::info`.
> I know the problem expanding the set of structural types is an orthogonal
> concern, but as AFAIK there is no proposal in the pipeline to address this,
> it's wise to take into account this limitation over string or string_view.
> As discussed in P3435, passing a name as template argument gives us the
> possibility of "lifting" members or emulating Swift keypaths.
>
> Perhaps this does not need to be in C++26 however I hope the door can be
> left open to make this change later, and P2296 already use the name
> `name_of` and `identifier_of`, which, if I may suggest, could be renamed
> `string_name_of`/`string_identifier_of`.
>
> Let me know what you think.
> -JB
>