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1 /***** BEGIN LICENSE BLOCK *****
2  * Version: CPL 1.0/GPL 2.0/LGPL 2.1
3  *
4  * The contents of this file are subject to the Common Public
5  * License Version 1.0 (the "License"); you may not use this file
6  * except in compliance with the License. You may obtain a copy of
7  * the License at http://www.eclipse.org/legal/cpl-v10.html
8  *
9  * Software distributed under the License is distributed on an "AS
10  * IS" basis, WITHOUT WARRANTY OF ANY KIND, either express or
11  * implied. See the License for the specific language governing
12  * rights and limitations under the License.
13  *
14  * Copyright (C) 2002 Benoit Cerrina <b.cerrina@wanadoo.fr>
15  * Copyright (C) 2002 Jan Arne Petersen <jpetersen@uni-bonn.de>
16  * Copyright (C) 2002-2004 Anders Bengtsson <ndrsbngtssn@yahoo.se>
17  * Copyright (C) 2004 Thomas E Enebo <enebo@acm.org>
18  * Copyright (C) 2004 Stefan Matthias Aust <sma@3plus4.de>
19  *
20  * Alternatively, the contents of this file may be used under the terms of
21  * either of the GNU General Public License Version 2 or later (the "GPL"),
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31  ***** END LICENSE BLOCK *****/
32 package org.jruby.ast;
33
34 import java.util.List JavaDoc;
35
36 import org.jruby.ast.visitor.NodeVisitor;
37 import org.jruby.evaluator.Instruction;
38 import org.jruby.lexer.yacc.ISourcePosition;
39
40 /**
41  * a Range in a boolean expression.
42  * named after a FlipFlop component in electronic I believe.
43  *
44  * @author jpetersen
45  */
46 public class FlipNode extends Node {
47     static final long serialVersionUID = -4735579451657299802L;
48
49     private final Node beginNode;
50     private final Node endNode;
51     private final boolean exclusive;
52     // A scoped location of this variable (high 16 bits is how many scopes down and low 16 bits
53 // is what index in the right scope to set the value.
54 private final int location;
55     
56     public FlipNode(ISourcePosition position, Node beginNode, Node endNode, boolean exclusive, int location) {
57         super(position, NodeTypes.FLIPNODE);
58         this.beginNode = beginNode;
59         this.endNode = endNode;
60         this.exclusive = exclusive;
61         this.location = location;
62     }
63
64     /**
65      * Accept for the visitor pattern.
66      * @param iVisitor the visitor
67      **/
68     public Instruction accept(NodeVisitor iVisitor) {
69         return iVisitor.visitFlipNode(this);
70     }
71
72     /**
73      * Gets the beginNode.
74      * beginNode will set the FlipFlop the first time it is true
75      * @return Returns a Node
76      */
77     public Node getBeginNode() {
78         return beginNode;
79     }
80
81     /**
82      * Gets the endNode.
83      * endNode will reset the FlipFlop when it is true while the FlipFlop is set.
84      * @return Returns a Node
85      */
86     public Node getEndNode() {
87         return endNode;
88     }
89
90     /**
91      * Gets the exclusive.
92      * if the range is a 2 dot range it is false if it is a three dot it is true
93      * @return Returns a boolean
94      */
95     public boolean isExclusive() {
96         return exclusive;
97     }
98
99     /**
100      * How many scopes should we burrow down to until we need to set the block variable value.
101      *
102      * @return 0 for current scope, 1 for one down, ...
103      */
104     public int getDepth() {
105         return location >> 16;
106     }
107     
108     /**
109      * Gets the index within the scope construct that actually holds the eval'd value
110      * of this local variable
111      *
112      * @return Returns an int offset into storage structure
113      */
114     public int getIndex() {
115         return location & 0xffff;
116     }
117     
118     public List JavaDoc childNodes() {
119         return Node.createList(beginNode, endNode);
120     }
121
122 }
123
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