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 
  26 package jdk.nashorn.internal.ir;
  27 
  28 import jdk.nashorn.internal.ir.annotations.Immutable;
  29 import jdk.nashorn.internal.ir.visitor.NodeVisitor;
  30 import 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
  38 public 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 }