code: function Recurring(str) {
    
    var parts = str.split('/');
  
    if(str.charAt(0) != 'R' || parts.length != 3) {
      throw new Error('Invalid Recurring Date');
    }
  
    // We must have start and end. error if both aren't set
    if(!parts[1] || !parts[2]) {
      throw new Error('Recurring must have a start and end');
    }
  
    var countNum = parts[0].substr(1);
  
    // Validate count is a number if set
    if(countNum) {
      if(!(/^[0-9]+$/.test(countNum))) {
        throw new Error('Invalid recurrence count: not a number')
      }
      this.count = parseInt(countNum, 10);
      if(this.count < 0) throw new Error('Invalid recurrence count');
    }
  
    Range.call(this, parts[1]+'/'+parts[2]);
  
    // If we have a count, replace end with the actual end date or undefined.
    delete this.end;
    if(this.count) {
      this.end = this.getNth(this.count);
    }
  }
docs: A GedcomX Recurring Date.