Basically what the title says. I know AS support pass value types by reference on parameters, but it is possible to define a reference to a value type in a method body? For example I've registered a C++ Vector2 as a value type, each operations returns a reference to itself for method chaining.

engine->RegisterObjectMethod("Vector2", "Vector2& add(const Vector2 &in)", asMETHODPR(Vector2, add, (Vector2&), Vector2&), asCALL_THISCALL);
engine->RegisterObjectMethod("Vector2", "Vector2& sub(const Vector2 &in)", asMETHODPR(Vector2, sub, (Vector2&), Vector2&), asCALL_THISCALL);

Then it can be possible to do in AngelScript the following? or should I register it as a reference type?

void main() {
	Vector2 A(1,5);
	Vector2 B(7,4);
	Vector2& directionAB = B.sub(A);
}

Thanks in advance

No, this is unfortunately not yet possible.

You can register vector2 as a reference type, but is it really worth it? Having it as a reference type, thus require a dynamic memory allocation on the heap for each instance, will create an overhead, not only in performance but also when interfacing with your application that expects normal value vector2 types.