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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
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9    * by Oracle in the LICENSE file that accompanied this code.
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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).
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17   * You should have received a copy of the GNU General Public License version
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25  package jdk.nashorn.internal.ir;
26  
27  import jdk.nashorn.internal.ir.visitor.NodeVisitor;
28  
29  
30  /**
31   * Interface for nodes that can be part of the lexical context.
32   * @see LexicalContext
33   */
34  public interface LexicalContextNode {
35      /**
36       * Accept function for the node given a lexical context. It must be prepared
37       * to replace itself if present in the lexical context
38       *
39       * @param lc      lexical context
40       * @param visitor node visitor
41       *
42       * @return new node or same node depending on state change
43       */
44      Node accept(final LexicalContext lc, final NodeVisitor<? extends LexicalContext> visitor);
45  
46      // Would be a default method on Java 8
47      /**
48       * Helper class for accept for items of this lexical context, delegates to the
49       * subclass accept and makes sure that the node is on the context before accepting
50       * and gets popped after accepting (and that the stack is consistent in that the
51       * node has been replaced with the possible new node resulting in visitation)
52       */
53      static class Acceptor {
54          static Node accept(final LexicalContextNode node, final NodeVisitor<? extends LexicalContext> visitor) {
55              final LexicalContext lc = visitor.getLexicalContext();
56              lc.push(node);
57              final LexicalContextNode newNode = (LexicalContextNode)node.accept(lc, visitor);
58              return (Node)lc.pop(newNode);
59          }
60      }
61  }