Dealing with property function and operator overloads
Andrej Mitrovic
andrej.mitrovich at gmail.com
Mon Oct 3 08:52:20 PDT 2011
Sample code:
struct Point
{
int x, y;
void opOpAssign(string op)(int rhs)
{
mixin("x = x " ~ op ~ " rhs;");
mixin("y = y " ~ op ~ " rhs;");
}
}
struct Wrapper
{
void notifyChanged() { }
@property void point(Point newpoint) { _p = newpoint; notifyChanged(); }
@property Point point() { return _p; }
private Point _p;
}
void main()
{
auto wrap = Wrapper();
wrap.point = Point(1, 1);
assert(wrap.point == Point(1, 1));
wrap.point += 1;
assert(wrap.point != Point(2, 2)); // oops
}
I want to get notified when the _p field is changed. A property
function works for assignments, but by using property functions I lose
any operator overloads Point might have.
I was thinking I could provide some sort of injecting mechanism into
the Point definition, so I could get rid of property functions and
instead do something like this:
struct Wrapper
{
this(...)
{
point.changed = ¬ifyChanged;
}
public Point point;
}
Has anyone ran into this issue before, and if so how did you work around it?
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