anchor.diff:      return new Fraction._(-numerator, denominator);
     }
   
  +  @override
     bool operator == (other) {
       return other is Fraction
           && numerator == other.numerator
           && denominator == other.denominator;
     }
   
  +  @override
     int get hashCode {
       return numerator.hashCode + denominator.hashCode;
     }
   
  +  @override
     int compareTo(Fraction other) {
       return (numerator * other.denominator)
           .compareTo(other.numerator * denominator);
  
positive.code: 
    int toInt() => numerator ~/ denominator;
  
    String toString() => '$numerator/$denominator';
  
  }
negative.code:  */
  library fraction;
  
  import 'package:meta/meta.dart';
  import 'int_math.dart' as int_math;
  
  /**
  