LexicalContextNode.java revision 953:221a84ef44c0 
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25package jdk.nashorn.internal.ir;
26
27import 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 */
34public 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}
62