sclass WithName<A> extends Var<A> {
  S name;
  
  *() {}
  *(A value) { super(value); }
  *(S *name, A value) { super(value); }
  
  toString {
    if (empty(name)) ret super.toString();
    ret name + ": " + super.toString();
  }
}

Began life as a copy of #1027095