Apropos, you can easily make your own date syntax in Dart:

  class Month {
    static const List<String> names = const <String>[
      "JAN", "FEB", "MAR", "APR", "MAY", "JUN", 
      "JUL", "AUG", "SEP", "OCT", "NOV", "DEC"                                                    
    ];
    final int month;
    const Month(this.month);
    MonthDay operator -(int day) => new MonthDay(month, day);
    String toString() => names[month - 1];
  }

  class MonthDay {
    final int month;
    final int day;
    MonthDay(this.month, this.day);
    DateTime operator -(int year) => new DateTime(year, month, day);
    String toString() => "${Month.names[month - 1]}-${"$day".padLeft(2, "0")}";
  }

  const Month JAN = const Month(1);
  const Month FEB = const Month(2);
  const Month MAR = const Month(3);
  const Month APR = const Month(4);
  const Month MAY = const Month(5);
  const Month JUN = const Month(6);
  const Month JUL = const Month(7);
  const Month AUG = const Month(8);
  const Month SEP = const Month(9);
  const Month OCT = const Month(10);
  const Month NOV = const Month(11);
  const Month DEC = const Month(12);

  main() {
    print(MAR-25-2015);
  }

Kudos! Truly, Dart has redeeming qualities! Incidentally, this code is the best argument I've seen for "American-style" date writing, with the month first. Or would it be as easy in Dart to override integers with a "DayMonth" operator?

I have no issue with zero-indexing. It is just inconsistent. Either everything should be zero index or nothing should. In this case nothing should.