/*
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 Copyright (c) 2005-2009 Terence Parr
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     derived from this software without specific prior written permission.

 THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
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package org.antlr.runtime.tree;

import org.antlr.runtime.Token;

import java.util.List;

What does a tree look like?  ANTLR has a number of support classes
 such as CommonTreeNodeStream that work on these kinds of trees.  You
 don't have to make your trees implement this interface, but if you do,
 you'll be able to use more support code.
 NOTE: When constructing trees, ANTLR can build any kind of tree; it can
 even use Token objects as trees if you add a child list to your tokens.
 This is a tree node without any payload; just navigation and factory stuff.
/** What does a tree look like?  ANTLR has a number of support classes
 *  such as CommonTreeNodeStream that work on these kinds of trees.  You
 *  don't have to make your trees implement this interface, but if you do,
 *  you'll be able to use more support code.
 *
 *  NOTE: When constructing trees, ANTLR can build any kind of tree; it can
 *  even use Token objects as trees if you add a child list to your tokens.
 *
 *  This is a tree node without any payload; just navigation and factory stuff.
 */
public interface Tree {
	public static final Tree INVALID_NODE = new CommonTree(Token.INVALID_TOKEN);

	Tree getChild(int i);

	int getChildCount();

	// Tree tracks parent and child index now > 3.0

	public Tree getParent();

	public void setParent(Tree t);

    
Is there is a node above with token type ttype? /** Is there is a node above with token type ttype? */
    public boolean hasAncestor(int ttype);

    
Walk upwards and get first ancestor with this token type. /** Walk upwards and get first ancestor with this token type. */
    public Tree getAncestor(int ttype);

    
Return a list of all ancestors of this node.  The first node of
 list is the root and the last is the parent of this node.
/** Return a list of all ancestors of this node.  The first node of
     *  list is the root and the last is the parent of this node.
     */
    public List<?> getAncestors();

    
This node is what child index? 0..n-1 /** This node is what child index? 0..n-1 */
	public int getChildIndex();

	public void setChildIndex(int index);

	
Set the parent and child index values for all children /** Set the parent and child index values for all children */
	public void freshenParentAndChildIndexes();

	
Add t as a child to this node.  If t is null, do nothing.  If t
 is nil, add all children of t to this' children.
/** Add t as a child to this node.  If t is null, do nothing.  If t
	 *  is nil, add all children of t to this' children.
	 */
	void addChild(Tree t);

	
Set ith child (0..n-1) to t; t must be non-null and non-nil node /** Set ith child (0..n-1) to t; t must be non-null and non-nil node */
	public void setChild(int i, Tree t);

	public Object deleteChild(int i);

	
Delete children from start to stop and replace with t even if t is
 a list (nil-root tree).  num of children can increase or decrease.
 For huge child lists, inserting children can force walking rest of
 children to set their childindex; could be slow.
/** Delete children from start to stop and replace with t even if t is
	 *  a list (nil-root tree).  num of children can increase or decrease.
	 *  For huge child lists, inserting children can force walking rest of
	 *  children to set their childindex; could be slow.
	 */
	public void replaceChildren(int startChildIndex, int stopChildIndex, Object t);	

	
Indicates the node is a nil node but may still have children, meaning
 the tree is a flat list.
/** Indicates the node is a nil node but may still have children, meaning
	 *  the tree is a flat list.
	 */
	boolean isNil();

	
 What is the smallest token index (indexing from 0) for this node
  and its children?
/**  What is the smallest token index (indexing from 0) for this node
	 *   and its children?
	 */
	int getTokenStartIndex();

	void setTokenStartIndex(int index);

	
 What is the largest token index (indexing from 0) for this node
  and its children?
/**  What is the largest token index (indexing from 0) for this node
	 *   and its children?
	 */
	int getTokenStopIndex();

	void setTokenStopIndex(int index);

	Tree dupNode();

	
Return a token type; needed for tree parsing /** Return a token type; needed for tree parsing */
	int getType();

	String getText();

	
In case we don't have a token payload, what is the line for errors? /** In case we don't have a token payload, what is the line for errors? */
	int getLine();

	int getCharPositionInLine();

	String toStringTree();

	@Override
	String toString();
}