anchor.diff:    Integer get successor => new Integer(this._value + 1);
   
     // Comparable
  -  Comparison compare([Float other])
  +  Comparison compare([Integer other])
         =>  _value < other._value ? smaller : (_value > other._value ? larger : equal);
   
     //Comparison compare(Integer other);
  
positive.code: 
    $dart$core.int get hashCode => _value.hashCode;
  
    // Comparable
    Comparison compare([Float other])
        =>  _value < other._value ? smaller : (_value > other._value ? larger : equal);
  
negative.code:     => length > 0 ? new String(this.sequence().terminal(length)) : String.instance("");
  
    //  shared actual native [String,String] slice(Integer index);
    Tuple slice([$dart$core.int length]) {
      var its = this.sequence().slice(length);
      return new Tuple.$withList([
          new String(its.getFromFirst(0)),
          new String(its.getFromFirst(1))]);
    }
  
    
    //  shared actual native Integer size;
    @$dart$core.override
    $dart$core.int get size => _value.runes.length;
  