Abstract methods in Dart

Question

I'm implementing an inheritance hierarchy in which derived-class construction consists only of a call to the base-class constructor. The base-class constructor then calls method(s) implemented only in the derived-class.

I have a basic implementation, but DartEditor of course complains about the missing methods in the base class. How can I make it happy?

Edit: I hadn't yet ran any code before posting my question, and it turns out that method binding works in the manner one would expect:

void main() {
    new B();
}

abstract class A {
    A() {
        x();
        y();
    }
    x() => print('A.x');
    y() => print('A.y');
}

class B extends A {
    B() : super();

    @override
    x() => print('B.x');
}

The above code outputs the following, which is the desired behavior. B's constructor calls A's constructor which calls x(). But since there is an x() defined for B, this is the one called:

B.x
A.y

It interesting to note that, although x() is being called by A's constructor, Dart somehow knows to call B's x(). I presume this is because the call chain looks roughly like the following:

B() -> A() -> B::x()

At runtime, Dart inspects the call chain to determine to which object to bind x().

Answer 1

From your question I would expect code like this

void main() {
 new B();
}

abstract class A {
  A() {
    a();
    b();
    c();
  }
  a();
  b();
  c();
}

class B extends A {
  B() : super();

  @override
  a() => print('a');
  @override
  b() => print('b');
  @override
  c() => print('c');
}

Try in DartPad

From your comment about getting an error I expect you don't have the abstract method stubs in the base class. Maybe this is what you are looking for

void main() {
 new B();
}

@proxy
abstract class A {
  A() {
    a();
    b();
    c();
  }
}

class B extends A {
  B() : super();

  a() => print('a');
  b() => print('b');
  c() => print('c');
}