lib/lexer.js
function() {
    var start = { line: this.lineno, column: this.column };
    var self = this;

    return function(node) {
      utils.define(node, 'position', new Position(start, self));
      return node;
    };
  }
function() {
    var start = { line: this.lineno, column: this.column };
    var self = this;

    return function(node) {
      utils.define(node, 'position', new Position(start, self));
      return node;
    };
  }
Mark position and patch `node.position`.