ReturnNode.java revision 1068:34ef988d5959 
1/*
2 * Copyright (c) 2010, 2013, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.  Oracle designates this
8 * particular file as subject to the "Classpath" exception as provided
9 * by Oracle in the LICENSE file that accompanied this code.
10 *
11 * This code is distributed in the hope that it will be useful, but WITHOUT
12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
14 * version 2 for more details (a copy is included in the LICENSE file that
15 * accompanied this code).
16 *
17 * You should have received a copy of the GNU General Public License version
18 * 2 along with this work; if not, write to the Free Software Foundation,
19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
20 *
21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
22 * or visit www.oracle.com if you need additional information or have any
23 * questions.
24 */
25
26package jdk.nashorn.internal.ir;
27
28import static jdk.nashorn.internal.parser.TokenType.RETURN;
29import static jdk.nashorn.internal.parser.TokenType.YIELD;
30
31import jdk.nashorn.internal.ir.annotations.Immutable;
32import jdk.nashorn.internal.ir.visitor.NodeVisitor;
33
34/**
35 * IR representation for RETURN or YIELD statements.
36 */
37@Immutable
38public class ReturnNode extends Statement {
39    private static final long serialVersionUID = 1L;
40
41    /** Optional expression. */
42    private final Expression expression;
43
44    /**
45     * Constructor
46     *
47     * @param lineNumber line number
48     * @param token      token
49     * @param finish     finish
50     * @param expression expression to return
51     */
52    public ReturnNode(final int lineNumber, final long token, final int finish, final Expression expression) {
53        super(lineNumber, token, finish);
54        this.expression = expression;
55    }
56
57    private ReturnNode(final ReturnNode returnNode, final Expression expression) {
58        super(returnNode);
59        this.expression = expression;
60    }
61
62    @Override
63    public boolean isTerminal() {
64        return true;
65    }
66
67    /**
68     * Return true if is a RETURN node.
69     * @return true if is RETURN node.
70     */
71    public boolean isReturn() {
72        return isTokenType(RETURN);
73    }
74
75    /**
76     * Check if this return node has an expression
77     * @return true if not a void return
78     */
79    public boolean hasExpression() {
80        return expression != null;
81    }
82
83    /**
84     * Return true if is a YIELD node.
85     * @return TRUE if is YIELD node.
86     */
87    public boolean isYield() {
88        return isTokenType(YIELD);
89    }
90
91    @Override
92    public Node accept(final NodeVisitor<? extends LexicalContext> visitor) {
93        if (visitor.enterReturnNode(this)) {
94            if (expression != null) {
95                return visitor.leaveReturnNode(setExpression((Expression)expression.accept(visitor)));
96            }
97            return visitor.leaveReturnNode(this);
98        }
99
100        return this;
101    }
102
103
104    @Override
105    public void toString(final StringBuilder sb, final boolean printType) {
106        sb.append(isYield() ? "yield" : "return");
107        if (expression != null) {
108            sb.append(' ');
109            expression.toString(sb, printType);
110        }
111    }
112
113    /**
114     * Get the expression this node returns
115     * @return return expression, or null if void return
116     */
117    public Expression getExpression() {
118        return expression;
119    }
120
121    /**
122     * Reset the expression this node returns
123     * @param expression new expression, or null if void return
124     * @return new or same return node
125     */
126    public ReturnNode setExpression(final Expression expression) {
127        if (this.expression == expression) {
128            return this;
129        }
130        return new ReturnNode(this, expression);
131    }
132
133}
134