import { CommonTree } from "./CommonTree.js";
/**
 * Return a node stream from a doubly-linked tree whose nodes know what child index they are. No remove() is supported.
 *
 * Emit navigation nodes (DOWN, UP, and EOF) to let show tree structure.
 */
export declare class TreeIterator {
    /** Navigation nodes to return during walk and at end. */
    static readonly up: CommonTree;
    static readonly down: CommonTree;
    static readonly eof: CommonTree;
    protected root: CommonTree | undefined;
    protected tree: CommonTree | undefined;
    protected firstTime: boolean;
    /** If we emit UP/DOWN nodes, we need to spit out multiple nodes per next() call. */
    protected nodes: CommonTree[];
    constructor(tree: CommonTree);
    reset(): void;
    hasNext(): boolean;
    nextTree(): CommonTree | undefined;
    remove(): void;
}