Associate information with a pointer address.

[bachmeier]

On Friday, 29 September 2023 at 14:31:54 UTC, BoQsc wrote:
> After being very happy about associative arrays of D Language, 
> I encountered that they are not `@nogc`friendly. Unsure if I 
> should wait for D language to support it, or do I need to 
> rethink everything.

You can work with AA's inside @nogc functions just fine as long 
as you don't do something that would cause a GC allocation. 
Consider this program:

```
import std;

@nogc double getValue(double[string] aa, string key) {
     return aa[key];
}

void main() {
     double[string] aa;
     aa["one"] = 1.0;
     aa["two"] = 2.0;
     writeln(aa.getValue("two"));
}
```

I'm not sure why you want to add elements inside a @nogc function 
- hard to say without knowing your use case. When I create an AA 
with many elements, I disable the GC, add a bunch of elements, 
and then turn it back on. Once the AA has been created, I can 
send it to @nogc functions for processing. I have a hard time 
believing there would be meaningful performance benefits doing 
anything further. (Though I can only speak to my experience, 
which of course does not include all applications.)