org.antlr.v4.runtime.tree.ParseTree.java Source code

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Here is the source code for org.antlr.v4.runtime.tree.ParseTree.java

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/*
 * 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;

import org.antlr.v4.runtime.Parser;
import org.antlr.v4.runtime.RuleContext;
import org.antlr.v4.runtime.Token;

/** An interface to access the tree of {@link RuleContext} objects created
 *  during a parse that makes the data structure look like a simple parse tree.
 *  This node represents both internal nodes, rule invocations,
 *  and leaf nodes, token matches.
 *
 *  <p>The payload is either a {@link Token} or a {@link RuleContext} object.</p>
 */
public interface ParseTree extends SyntaxTree {
    // the following methods narrow the return type; they are not additional methods
    @Override
    ParseTree getParent();

    @Override
    ParseTree getChild(int i);

    /** Set the parent for this node.
     *
     *  This is not backward compatible as it changes
     *  the interface but no one was able to create custom
     *  nodes anyway so I'm adding as it improves internal
     *  code quality.
     *
     *  One could argue for a restructuring of
     *  the class/interface hierarchy so that
     *  setParent, addChild are moved up to Tree
     *  but that's a major change. So I'll do the
     *  minimal change, which is to add this method.
     *
     *  @since 4.7
     */
    void setParent(RuleContext parent);

    /** The {@link ParseTreeVisitor} needs a double dispatch method. */
    <T> T accept(ParseTreeVisitor<? extends T> visitor);

    /** Return the combined text of all leaf nodes. Does not get any
     *  off-channel tokens (if any) so won't return whitespace and
     *  comments if they are sent to parser on hidden channel.
     */
    String getText();

    /** Specialize toStringTree so that it can print out more information
     *    based upon the parser.
     */
    String toStringTree(Parser parser);
}