Problem with Point property

[Hasan Aljudy]

Henning Hasemann wrote:
> Hi all, say I have a structure Point and an attribute position like this:
> 
> struct Point {
>   int x, y;
> }
> 
> class Foo {
>   Point position;
> }
> 
> So far, so good. Now I want to substitude the attribute with a property
> (because I want to react on changes of the position immediately)
> The setter is no Problem:
> 
>   void position(Point p) { mPosition = p; react(); }
> 
> The getter indeed is. If I wrote:
> 
>   Point position() { return mPosition; }
> 
> this would break expressions like
> 
> Foo().position.x = 5;
> 
> which I happen to use often.
> The solutions I see are
> 
> * Return a proxy object instead of a real Point.
>   Bad because the return type is not Point anymore.
> 
> * Return a Point*, would break types too I dont
>   know if these two even work.
> 
> * Turn Point into a class so I return a reference.
>   Possible, but Point really just carries 2 integers
>   and I either had to change all "Point(...)"'s into "new Point(...)"'s,
>   or implement opCall for a class which I'm not sure if it is the best
>   option, since it may be misleading.
> 
> Are there other ways? Can I somehow return a reference to a struct
> without "leaving" the type?
> 
> What would you do?
> 
> TIA,
> Henning
> 

If you return a pointer, you can still use the . operator, so I think
foo().point.x;
should work just fine (both syntactically and semantically)

However the implication is that if you have a function that takes a 
point struct object, you either have to change that function to take a 
point pointer, or dereference the property every time you pass it to 
functions.