code: function MDVars(root, prop) {
  
    // Ensure new were used
    if(!(this instanceof MDVars)) {
      return new MDVars(root, prop);
    }
  
    // Parent constructor
    PassThrough.call(this);
  
    // Instantiate an internal VarStream
    this._varstream = new VarStream(root, prop);
  
    // Parsing states
    this._parsingVars = false;
    this._parsingRank = 0;
  }
docs: Constructor