Returning a struct by reference

Simon TRENY simon.treny at free.fr
Sat Mar 21 06:12:24 PDT 2009


Hi there!

I'm quite new at D and I'm still just playing with it, but there is a thing that I find currently missing. Sometimes, I'd like to be able to return a struct by reference and not by value. For example, in the following example:

struct Position {
   float x;
   float y;
}

class Object {
   private Position m_position;

   public Position position() {
      return m_position;
   }
}

I'd like to be able to write things like this: myObject.position.x = 43 to actually change the position of the object. But right now, since "position" is a struct, it is returned by value and not by reference, and then the previous instruction won't change the position of the object, but it will work on a copy of the position field.


Here is the solutions that I can see to this problem:

- Returning a pointer to the position: "public Position *position() { ... }", but I'd like to keep my code as free from pointers as possible.
 - Make "Position" a class and not a struct. That could be a solution, but then, when I'll do things like "Position pos = object.position; pos.x = 43;", it will effectively change the position of the object, which I wouldn't like with this syntax.

Actually, I'd like to be able to do a thing like this:
   public ref Position position() {
      return m_position;
   }
which would be the equivalent form to passing structs by reference in a parameter.

Is there a way to do this in D?

Regards,
Simon




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