/* -*- Mode: java; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*-
 *
 * ***** BEGIN LICENSE BLOCK *****
 * Version: MPL 1.1/GPL 2.0
 *
 * The contents of this file are subject to the Mozilla Public License Version
 * 1.1 (the "License"); you may not use this file except in compliance with
 * the License. You may obtain a copy of the License at
 * http://www.mozilla.org/MPL/
 *
 * Software distributed under the License is distributed on an "AS IS" basis,
 * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
 * for the specific language governing rights and limitations under the
 * License.
 *
 * The Original Code is Rhino code, released
 * May 6, 1999.
 *
 * The Initial Developer of the Original Code is
 * Netscape Communications Corporation.
 * Portions created by the Initial Developer are Copyright (C) 1997-1999
 * the Initial Developer. All Rights Reserved.
 *
 * Contributor(s):
 *   Steve Yegge
 *
 * Alternatively, the contents of this file may be used under the terms of
 * the GNU General Public License Version 2 or later (the "GPL"), in which
 * case the provisions of the GPL are applicable instead of those above. If
 * you wish to allow use of your version of this file only under the terms of
 * the GPL and not to allow others to use your version of this file under the
 * MPL, indicate your decision by deleting the provisions above and replacing
 * them with the notice and other provisions required by the GPL. If you do
 * not delete the provisions above, a recipient may use your version of this
 * file under either the MPL or the GPL.
 *
 * ***** END LICENSE BLOCK ***** */

package org.mozilla.javascript.ast;

/**
 * Simple visitor interface for traversing the AST.  The nodes are visited in
 * an arbitrary order.  The visitor must cast nodes to the appropriate
 * type based on their token-type.
 */
public interface NodeVisitor {

    /**
     * Visits an AST node.
     * @param node the AST node.  Will never visit an {@link AstRoot} node,
     * since the {@code AstRoot} is where the visiting begins.
     * @return {@code true} if the children should be visited.
     * If {@code false}, the subtree rooted at this node is skipped.
     * The {@code node} argument should <em>never</em> be {@code null} --
     * the individual {@link AstNode} classes should skip any children
     * that are not present in the source when they invoke this method.
     */
    boolean visit(AstNode node);
}
