Re: opIndexUnary post in-/decrement how to ?

[Tejas via Digitalmars-d-learn]

On Wednesday, 14 July 2021 at 15:23:05 UTC, vit wrote:

On Wednesday, 14 July 2021 at 15:19:03 UTC, vit wrote:


```d
import   std.stdio;

struct abc{
    int[100] a;

    struct Proxy{
        abc* ptr;
        const int index;

        int opUnary(string op : "++")(){
                return ++ptr.a[index];     //add missing ++
        }
    }

    Proxy opIndex(int index)return{
        return Proxy(&this, index);
    }
}

void main (){
    abc s;
    s[0]++;
    ++s[0];
}


```

I tried changing ```s[0]++``` to ``` s[0] += 1```

the same lvalue problem arose :(

```

Error: `s.opIndex(0)` is not an lvalue and cannot be modified

```