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14  * Copyright (C) 2006 Thomas E Enebo <enebo@acm.org>
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28 package org.jruby.ast;
29
30 import java.util.List JavaDoc;
31
32 import org.jruby.ast.visitor.NodeVisitor;
33 import org.jruby.evaluator.Instruction;
34 import org.jruby.lexer.yacc.ISourcePosition;
35 import org.jruby.parser.StaticScope;
36 import org.jruby.runtime.DynamicScope;
37
38 /**
39  * Represents the top of the AST. This is a node not present in MRI. It was created to
40  * hold the top-most static scope in an easy to grab way and it also exists to hold BEGIN
41  * and END nodes. These can then be interpreted/compiled in the same places as the rest
42  * of the code.
43  *
44  */
45 // TODO: Store BEGIN and END information into this node
46 // TODO: Implement BEGIN and END logic so they get invoked at the correct time.
47 public class RootNode extends Node {
48     private static final long serialVersionUID = 1754281364026417051L;
49     
50     private transient DynamicScope scope;
51     private StaticScope staticScope;
52     private Node bodyNode;
53
54     public RootNode(ISourcePosition position, DynamicScope scope, Node bodyNode) {
55         super(position, NodeTypes.ROOTNODE);
56         
57         this.scope = scope;
58         this.staticScope = scope.getStaticScope();
59         this.bodyNode = bodyNode;
60     }
61     
62     /**
63      * Return the dynamic scope for this AST. The variable backed by this is transient so
64      * for serialization this is null. In that case we use staticScope to rebuild the dynamic
65      * scope. The real reason for this method is supporting bindings+eval. We need to pass
66      * our live dynamic scope in so when we eval we can use that dynamic scope.
67      *
68      * @return dynamic scope of this AST
69      */
70     public DynamicScope getScope() {
71         return scope;
72     }
73     
74     /**
75      * The static scoping relationships that should get set first thing before interpretation
76      * of the code represented by this AST. Actually, we use getScope first since that also
77      * can contain a live dynamic scope. We rely on this method only for interpreting a root
78      * node from a serialized format.
79      *
80      * @return the top static scope for the AST
81      */
82     public StaticScope getStaticScope() {
83         return staticScope;
84     }
85     
86     /**
87      * First real AST node to be interpreted
88      *
89      * @return real top AST node
90      */
91     public Node getBodyNode() {
92         return bodyNode;
93     }
94
95     public Instruction accept(NodeVisitor iVisitor) {
96         return iVisitor.visitRootNode(this);
97     }
98
99     public List JavaDoc childNodes() {
100         return createList(bodyNode);
101     }
102
103 }
104
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