Re: using enum in for loop.

for (auto e: <type>) seems weird (and messes with the grammar). And
opens the door to 'for ( auto e : unsigned char )', or 'for (auto e :
long)'. Yes, I realize that's not what you're asking for now, but it
seems like a natural next step.

Also two other clarifications would also need to happen: what about
duplicate values, and in what order will that loop across the enum
values (recall: one can define an enum in an arbitrary order).

On Fri, Mar 14, 2025 at 9:43 AM Filip via Std-Proposals
<std-proposals_at_[hidden]> wrote:
>
> I want to ask for your comments about couple of different for loops ideas that I had recently:
>
> 1. using enum in for loop:
> ```
> for (auto e : someEnum) {...}
> ```
>
> Since compiler knows the elements of `ENUM` it should be able to easily unroll the loop or iterate over the elements of enum.
>
> 2. Forcing unroll with a keyword and not `#pragma`
> ```
> inline for ( … )
> ```
> It could force the unroll like similar construct does in zig.
> This syntax already exists and we could probably easily implement it.
>
> 3. Run loop N times
> ```
> for ( 5 )
> ```
> Running for loop N number of times is a common issue e.g. N tries to connect to the server.
> This way would not pollute the namespace with additional `int i` that we frankly don’t use.
> --
> Std-Proposals mailing list
> Std-Proposals_at_[hidden]
> https://lists.isocpp.org/mailman/listinfo.cgi/std-proposals