<?php

namespace PhpParser;

interface NodeTraverserInterface
{
    /**
     * If NodeVisitor::enterNode() returns DONT_TRAVERSE_CHILDREN, child nodes
     * of the current node will not be traversed for any visitors.
     *
     * For subsequent visitors enterNode() will still be called on the current
     * node and leaveNode() will also be invoked for the current node.
     */
    const DONT_TRAVERSE_CHILDREN = 1;

    /**
     * If NodeVisitor::leaveNode() returns REMOVE_NODE for a node that occurs
     * in an array, it will be removed from the array.
     *
     * For subsequent visitors leaveNode() will still be invoked for the
     * removed node.
     */
    const REMOVE_NODE = false;

    /**
     * Adds a visitor.
     *
     * @param NodeVisitor $visitor Visitor to add
     */
    function addVisitor(NodeVisitor $visitor);

    /**
     * Removes an added visitor.
     *
     * @param NodeVisitor $visitor
     */
    function removeVisitor(NodeVisitor $visitor);

    /**
     * Traverses an array of nodes using the registered visitors.
     *
     * @param Node[] $nodes Array of nodes
     *
     * @return Node[] Traversed array of nodes
     */
    function traverse(array $nodes);
}