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 jdk.nashorn.internal.ir.annotations.Immutable;
29import jdk.nashorn.internal.ir.visitor.NodeVisitor;
30import jdk.nashorn.internal.parser.TokenType;
31
32/**
33 * IR representation for executing bare expressions. Basically, an expression
34 * node means "this code will be executed" and evaluating it results in
35 * statements being added to the IR
36 */
37@Immutable
38public final class ExpressionStatement extends Statement {
39    private static final long serialVersionUID = 1L;
40
41    /** Expression to execute. */
42    private final Expression expression;
43    private final TokenType destructuringDecl;
44
45    /**
46     * Constructor
47     *
48     * @param lineNumber line number
49     * @param token      token
50     * @param finish     finish
51     * @param expression the expression to execute
52     * @param destructuringDecl does this statement represent a destructuring declaration?
53     */
54    public ExpressionStatement(final int lineNumber, final long token, final int finish,
55            final Expression expression, final TokenType destructuringDecl) {
56        super(lineNumber, token, finish);
57        this.expression = expression;
58        this.destructuringDecl = destructuringDecl;
59    }
60
61    /**
62     * Constructor
63     *
64     * @param lineNumber line number
65     * @param token      token
66     * @param finish     finish
67     * @param expression the expression to execute
68     */
69    public ExpressionStatement(final int lineNumber, final long token, final int finish, final Expression expression) {
70        this(lineNumber, token, finish, expression, null);
71    }
72
73    private ExpressionStatement(final ExpressionStatement expressionStatement, final Expression expression) {
74        super(expressionStatement);
75        this.expression = expression;
76        this.destructuringDecl = null;
77    }
78
79    @Override
80    public Node accept(final NodeVisitor<? extends LexicalContext> visitor) {
81        if (visitor.enterExpressionStatement(this)) {
82            return visitor.leaveExpressionStatement(setExpression((Expression)expression.accept(visitor)));
83        }
84
85        return this;
86    }
87
88    @Override
89    public void toString(final StringBuilder sb, final boolean printTypes) {
90        expression.toString(sb, printTypes);
91    }
92
93    /**
94     * Return the expression to be executed
95     * @return the expression
96     */
97    public Expression getExpression() {
98        return expression;
99    }
100
101    /**
102     * Return declaration type if this expression statement is a destructuring declaration
103     *
104     * @return declaration type (LET, VAR, CONST) if destructuring declaration, null otherwise.
105     */
106    public TokenType destructuringDeclarationType() {
107        return destructuringDecl;
108    }
109
110    /**
111     * Reset the expression to be executed
112     * @param expression the expression
113     * @return new or same execute node
114     */
115    public ExpressionStatement setExpression(final Expression expression) {
116        if (this.expression == expression) {
117            return this;
118        }
119        return new ExpressionStatement(this, expression);
120    }
121}
122