Dlang - Is there a way to embed objects in objects?

Question

According to the D specification all classes are accessed by reference which would mean that the following class would be layed out in memory as follows.

Pseudocode:

class A
{
    public int c;
    public B b;
}

Memory layout of an object of type A:

4 bytes | int c

(4/8) bytes | address of b

Is there a way to create a class that would embed b directly in A instead of having a reference? Or am I overlooking something?

Answer 1

Scoped turns out to be better than I thought, you can also use emplace which is a bit more cumbersome in this simple case but may come in handy:

class A {
    import std.conv;

    public  B b;

    // We can't just use sizeof here because we want the size of the
    // instance, not the reference.
    private void[__traits(classInstanceSize, B)] b_space;

    this() {
        b = emplace!B(b_space);
    }
}