/*
 * Copyright (c) 2012-2017 The ANTLR Project. All rights reserved.
 * Use of this file is governed by the BSD 3-clause license that
 * can be found in the LICENSE.txt file in the project root.
 */

package org.antlr.v4.runtime.tree;

This interface defines the basic notion of a parse tree visitor. Generated visitors implement this interface and the XVisitor interface for grammar X.
Type parameters:
  • <T> – The return type of the visit operation. Use Void for operations with no return type.
/** * This interface defines the basic notion of a parse tree visitor. Generated * visitors implement this interface and the {@code XVisitor} interface for * grammar {@code X}. * * @param <T> The return type of the visit operation. Use {@link Void} for * operations with no return type. */
public interface ParseTreeVisitor<T> {
Visit a parse tree, and return a user-defined result of the operation.
Params:
Returns:The result of visiting the parse tree.
/** * Visit a parse tree, and return a user-defined result of the operation. * * @param tree The {@link ParseTree} to visit. * @return The result of visiting the parse tree. */
T visit(ParseTree tree);
Visit the children of a node, and return a user-defined result of the operation.
Params:
  • node – The RuleNode whose children should be visited.
Returns:The result of visiting the children of the node.
/** * Visit the children of a node, and return a user-defined result of the * operation. * * @param node The {@link RuleNode} whose children should be visited. * @return The result of visiting the children of the node. */
T visitChildren(RuleNode node);
Visit a terminal node, and return a user-defined result of the operation.
Params:
Returns:The result of visiting the node.
/** * Visit a terminal node, and return a user-defined result of the operation. * * @param node The {@link TerminalNode} to visit. * @return The result of visiting the node. */
T visitTerminal(TerminalNode node);
Visit an error node, and return a user-defined result of the operation.
Params:
Returns:The result of visiting the node.
/** * Visit an error node, and return a user-defined result of the operation. * * @param node The {@link ErrorNode} to visit. * @return The result of visiting the node. */
T visitErrorNode(ErrorNode node); }