How to register factory of part in Dart - class

Question

I have a lot of part of library. But all of the same type (extends Part)
part1.dart
part of Parts;
class Part1 extends Part { /* ... */ }
parts.add((varOfSomeClass){ return new Part1(varOfSomeClass + 1); });
part2.dart
part of Parts;
class Part2 extends Part { /* ... */ }
parts.add((varOfSomeClass){ return new Part2(varOfSomeClass - 1); });
parts.dart
library Parts;
part "Part1.dart";
part "Part2.dart";
List<Function> parts = new List<Function>();
class Parts {
getPart(int index) {
if (parts.contains(index)) {
return parts[index](someVarOfThisClass);
}
}
}
OUTPUT: error: unexpected token 'parts'
How to get all included factories without create instance all the Part classes?
For example need to do:
BMW.dart
part of Auto;
class BMW {
String color;
BMW(this.color);
}
list.add((color){
return new BMW(color);
});
Lada.dart
part of Auto;
class Lada {
List<int> color;
}
list.add((color){
var auto = new Lada();
auto.color = hex2rgb(color);
return auto;
});
Auto.dart
library Auto;
class Auto {
getByIndex(int index) {
if (list.contains(index)) {
return list[index](color);
}
return null;
}
}

Answer 1

Looks like your problem is that you have code outside of a class or function definition. If I'm guessing what you want to do correctly, you want BMW.dart to look something like
part of Auto;
class BMW {
String color;
BMW(this.color);
}
and then in your main() method have code like
main() {
List list = [];
list.add((color) => new BMW(color));
}
This will get the code above running. It's probably not the best way to structure your program though. You may want to do some more reading on Dart factory constructors. https://www.dartlang.org/dart-tips/dart-tips-ep-11.html is a good place to start.

Answer 2

I don't know what you need it for but how about using mirrors:
main.dart
library cars;
import 'dart:mirrors';
part 'bmw.dart';
part 'audi.dart';
abstract class Car {
}
void main() {
List<Car> cars = new List<Car>();
Map libraries = currentMirrorSystem().libraries;
LibraryMirror mirror = libraries[libraries.keys.last];
mirror.declarations.forEach((Symbol s, DeclarationMirror mirror) {
if(mirror is ClassMirror) {
if(!mirror.isAbstract && mirror.isAssignableTo(reflectType(Car))) {
// new Symbol(mirror.reflectedType.toString()))
cars.add(mirror.newInstance(#Car, []).reflectee);
}
}
});
print(cars);
}
bmw.dart
part of cars;
class Bmw extends Car {
Bmw.Car() {
}
}
audi.dart
part of cars;
class Audi extends Car {
Audi.Car() {
}
}