/**
 * @license
 * Copyright (c) 2016 The Polymer Project Authors. All rights reserved.
 * This code may only be used under the BSD style license found at
 * http://polymer.github.io/LICENSE.txt The complete set of authors may be found
 * at http://polymer.github.io/AUTHORS.txt The complete set of contributors may
 * be found at http://polymer.github.io/CONTRIBUTORS.txt Code distributed by
 * Google as part of the polymer project is also subject to an additional IP
 * rights grant found at http://polymer.github.io/PATENTS.txt
 */
/**
 * Class that implements a visitor pattern for ASTs produced by the Parser.
 * Extend the NodeVisitor class to implement useful tree traversal operations
 * such as stringification.
 */
declare class NodeVisitor<Node extends {
    type: any;
}, ReturnValue> {
    private path_;
    /**
     * Create a NodeVisitor instance.
     */
    constructor();
    /**
     * A list of nodes that corresponds to the current path through an AST being
     * visited, leading to where the currently visited node will be found.
     */
    readonly path: Node[];
    /**
     * Visit a node. The visited node will be added to the `path` before it is
     * visited, and will be removed after it is visited. Nodes are "visited" by
     * calling a method on the NodeVisitor instance that matches the node's type,
     * if one is available on the NodeVisitor instance.
     * @param node The node to be visited.
     * @return The return value of the method visiting the node, if any.
     */
    visit(node: Node): ReturnValue | undefined;
}
export { NodeVisitor };