org.antlr.v4.runtime.tree.Tree Maven / Gradle / Ivy
/*
* 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.RuleContext;
import org.antlr.v4.runtime.Token;
/** The basic notion of a tree has a parent, a payload, and a list of children.
* It is the most abstract interface for all the trees used by ANTLR.
*/
public interface Tree {
/** The parent of this node. If the return value is null, then this
* node is the root of the tree.
*/
Tree getParent();
/**
* This method returns whatever object represents the data at this node. For
* example, for parse trees, the payload can be a {@link Token} representing
* a leaf node or a {@link RuleContext} object representing a rule
* invocation. For abstract syntax trees (ASTs), this is a {@link Token}
* object.
*/
Object getPayload();
/** If there are children, get the {@code i}th value indexed from 0. */
Tree getChild(int i);
/** How many children are there? If there is none, then this
* node represents a leaf node.
*/
int getChildCount();
/** Print out a whole tree, not just a node, in LISP format
* {@code (root child1 .. childN)}. Print just a node if this is a leaf.
*/
String toStringTree();
}