Question

I have the following variable and getter / setter defined in my data model:

class Actor {
    int _x;
    int get x => _x;
    set x(int value) => _x = value;
}

And there is this generic class that requires a getter / setter function pointer

class PropertyItem {
   var getterFunction;
   var setterFunction;
   PropertyItem(this.getterFunction, this.setterFunction);
}

How do i pass a reference of the getter / setter function of X to the PropertyItem class?

// Something like this
var item = new PropertyItem(x.getter, x.setter);

EDIT: Updated with a more clear question

Answer 1

In short, you don’t.
Getters and setters are not extractable – they are indistinguishable from just having a field (if you don’t do side-effects, of course).

In your example, you could just do:

class Actor {
  int x;
} 

and get exactly the same effect.

What you want is, for some Actor “actor”, to make the functions yourself:

var item = new PropertyItem(() => actor.x, (v) { actor.x = v; });

This proposal about generalized tear offs is approved and will probably implemented soon and allows to closurize getters and setters like:

var item = new PropertyItem(actor#x, actor#x=);