/*
 * [The "BSD license"]
 *  Copyright (c) 2012 Terence Parr
 *  Copyright (c) 2012 Sam Harwell
 *  All rights reserved.
 *
 *  Redistribution and use in source and binary forms, with or without
 *  modification, are permitted provided that the following conditions
 *  are met:
 *
 *  1. Redistributions of source code must retain the above copyright
 *     notice, this list of conditions and the following disclaimer.
 *  2. Redistributions in binary form must reproduce the above copyright
 *     notice, this list of conditions and the following disclaimer in the
 *     documentation and/or other materials provided with the distribution.
 *  3. The name of the author may not be used to endorse or promote products
 *     derived from this software without specific prior written permission.
 *
 *  THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
 *  IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 *  OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 *  IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
 *  INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 *  NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 *  DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 *  THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 *  (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 *  THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

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);

	/** 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);
}