On Sunday, 15 August 2021 at 07:10:17 UTC, JG wrote:
Hi,
This is exactly the behaviour I was trying to obtain.
It however comes with a fair amount of overhead, as can be seen
in the following llvm ir:
[...]
What you are asking for are reference variables. C++ has them:
the example here illustrates the behavior you want.
https://www.geeksforgeeks.org/references-in-c/
D does not have them, as mentioned above:
https://forum.dlang.org/post/mailman.2714.1628875187.3446.digitalmars-d-le...@puremagic.com
So to get the behavior you want, they have to be simulated, which
is what this does:
https://forum.dlang.org/post/lcrrnszslpyazoziy...@forum.dlang.org
Next version: no `toString` and storage passed in by reference
rather than by pointer.
```
struct S {
int x = 1234;
}
void main() {
import std.stdio;
S s;
auto p = &s.x;
//construction of a using &(s.x)
auto a = Ref!(int)(*p);
//auto a = Ref!(int)(s.x);
writeln(a); //displays 1234
s.x += 1;
writeln(a); //displays 1235
a += 1;
writeln(s.x); //displays 1236
}
struct Ref(T)
{
T* ptr;
this(ref T x) { ptr = &x; }
@property ref T var() { return *ptr; }
alias var this;
}
```
I see no way to avoid overhead, as I see no simpler simulation.
