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 static jdk.nashorn.internal.parser.TokenType.RETURN; 29 import static jdk.nashorn.internal.parser.TokenType.YIELD; 30 31 import jdk.nashorn.internal.ir.annotations.Immutable; 32 import jdk.nashorn.internal.ir.visitor.NodeVisitor; 33 34 /** 35 * IR representation for RETURN or YIELD statements. 36 */ 37 @Immutable 38 public 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 }