/* -*- 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
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package org.mozilla.javascript.ast;

import org.mozilla.javascript.Token;

/**
 * AST node for JavaScript 1.7 {@code yield} expression or statement.
 * Node type is {@link Token#YIELD}.<p>
 *
 * <pre><i>Yield</i> :
 *   <b>yield</b> [<i>no LineTerminator here</i>] [non-paren Expression] ;</pre>
 */
public class Yield extends AstNode {

    private AstNode value;

    {
        type = Token.YIELD;
    }

    public Yield() {
    }

    public Yield(int pos) {
        super(pos);
    }

    public Yield(int pos, int len) {
        super(pos, len);
    }

    public Yield(int pos, int len, AstNode value) {
        super(pos, len);
        setValue(value);
    }

    /**
     * Returns yielded expression, {@code null} if none
     */
    public AstNode getValue() {
        return value;
    }

    /**
     * Sets yielded expression, and sets its parent to this node.
     * @param expr the value to yield. Can be {@code null}.
     */
    public void setValue(AstNode expr) {
        this.value = expr;
        if (expr != null)
            expr.setParent(this);
    }

    @Override
    public String toSource(int depth) {
        return value == null
                ? "yield"
                : "yield " + value.toSource(0);
    }

    /**
     * Visits this node, and if present, the yielded value.
     */
    @Override
    public void visit(NodeVisitor v) {
        if (v.visit(this) && value != null) {
            value.visit(v);
        }
    }
}
