neutral_ex_Case_b.ts

function ForwardDeclareClasses(topics: ReadonlyArray<TypedTopic>): ClassMap {
  // ...
  // ...
  for (const topic of topics) {
    if (!IsClass(topic)) continue;

    // ...
    classes.set(
        topic.Subject.toString(), new Class(topic.Subject, /* ... */));
  }
  // ...
  return classes;
}

function BuildClasses(topics: ReadonlyArray<TypedTopic>, classes: ClassMap) {
  for (const topic of topics) {
    if (!IsClass(topic)) continue;

    const cls = classes.get(topic.Subject.toString());
    if (!cls) {
      throw new Error(/**... class should have been forward declared */);
    }
    toClass(cls, topic, classes);
  }
}