extending foreach for keyed ranges and other usage of datastructures

[Quirin Schroll]

On Wednesday, 15 May 2024 at 20:27:12 UTC, monkyyy wrote:
> extend the api of foreach to allow for 
> `foreach(key,value;data)` for user data types,
>  and user defined "autodecoding"
>
> […]

Can’t `opApply` not already do that?