What is the dart function type syntax for variable declaration?

Question

I know you can specify function types in formal arg list, but how would I do this for instance variables? I would like to do this:

class A<T> {   int compare(T a, T b); } 

where compare is a function variable with the appropriate type. I would like to be able to write:

A a = new A(); a.compare = ... 

Answer 1

You can use typedef :

typedef Comparison<T> = int Function(T a, T b);  class A<T> {   Comparison<T> compare; }  main() {   A a = new A<int>();   a.compare = (int a, int b) => a.compareTo(b);   print(a.compare(1, 2)); }