main.dart

import "./point.dart";
import "./print.dart";

void main() {
  var p = new Point(1, 2);
  printPoint(p);
}

point.dart

class Point {
  num x;
  num y;

  Point(this.x, this.y);
}

print.dart

import "./point.dart";

void printPoint(Point p) {
  print("Point: (${p.x}, ${p.y})");
}