nav-menu-template

<?php

class WPT_Custom_Walker_Nav_Menu extends Walker {
    /**
     * What the class handles.
     *
     * @see Walker::$tree_type
     * @since 3.0.0
     * @var string
     */
    public $tree_type = array( 'post_type', 'taxonomy', 'custom' );

    /**
     * Database fields to use.
     *
     * @see Walker::$db_fields
     * @since 3.0.0
     * @todo Decouple this.
     * @var array
     */
    public $db_fields = array( 'parent' => 'menu_item_parent', 'id' => 'db_id' );

    /**
     * Starts the list before the elements are added.
     *
     * @see Walker::start_lvl()
     *
     * @since 3.0.0
     *
     * @param string $output Passed by reference. Used to append additional content.
     * @param int    $depth  Depth of menu item. Used for padding.
     * @param array  $args   An array of arguments. @see wp_nav_menu()
     */
    public function start_lvl( &$output, $depth = 0, $args = array() ) {
        $indent = str_repeat("\t", $depth);
        $output .= "\n$indent<ul class=\"sub-menu\">\n";
    }

    /**
     * Ends the list of after the elements are added.
     *
     * @see Walker::end_lvl()
     *
     * @since 3.0.0
     *
     * @param string $output Passed by reference. Used to append additional content.
     * @param int    $depth  Depth of menu item. Used for padding.
     * @param array  $args   An array of arguments. @see wp_nav_menu()
     */
    public function end_lvl( &$output, $depth = 0, $args = array() ) {
        $indent = str_repeat("\t", $depth);
        $output .= "$indent</ul>\n";
    }

<?php
/**
 * Nav Menu API: Template functions
 *
 * @package WordPress
 * @subpackage Nav_Menus
 * @since 3.0.0
 */

/** Walker_Nav_Menu class */
require_once ABSPATH . WPINC . '/class-walker-nav-menu.php';

/**
 * Displays a navigation menu.
 *
 * @since 3.0.0
 * @since 4.7.0 Added the `item_spacing` argument.
 *
 * @staticvar array $menu_id_slugs
 *
 * @param array $args {
 *     Optional. Array of nav menu arguments.
 *
 *     @type int|string|WP_Term $menu            Desired menu. Accepts (matching in order) id, slug, name, menu object. Default empty.
 *     @type string             $menu_class      CSS class to use for the ul element which forms the menu. Default 'menu'.
 *     @type string             $menu_id         The ID that is applied to the ul element which forms the menu.
 *                                               Default is the menu slug, incremented.
 *     @type string             $container       Whether to wrap the ul, and what to wrap it with. Default 'div'.
 *     @type string             $container_class Class that is applied to the container. Default 'menu-{menu slug}-container'.
 *     @type string             $container_id    The ID that is applied to the container. Default empty.
 *     @type callable|bool      $fallback_cb     If the menu doesn't exists, a callback function will fire.
 *                                               Default is 'wp_page_menu'. Set to false for no fallback.
 *     @type string             $before          Text before the link markup. Default empty.
 *     @type string             $after           Text after the link markup. Default empty.
 *     @type string             $link_before     Text before the link text. Default empty.
 *     @type string             $link_after      Text after the link text. Default empty.
 *     @type bool               $echo            Whether to echo the menu or return it. Default true.
 *     @type int                $depth           How many levels of the hierarchy are to be included. 0 means all. Default 0.
 *     @type object             $walker          Instance of a custom walker class. Default empty.
 *     @type string             $theme_location  Theme location to be used. Must be registered with register_nav_menu()
 *                                               in order to be selectable by the user.
 *     @type string             $items_wrap      How the list items should be wrapped. Default is a ul with an id and class.
 *                                               Uses printf() format with numbered placeholders.
 *     @type string             $item_spacing    Whether to preserve whitespace within the menu's HTML. Accepts 'preserve' or 'discard'. Default 'preserve'.
 * }
 * @return object|false|void Menu output if $echo is false, false if there are no items or no menu was found.
 */
function wp_nav_menu( $args = array() ) {
    static $menu_id_slugs = array();

    $defaults = array( 'menu' => '', 'container' => 'div', 'container_class' => '', 'container_id' => '', 'menu_class' => 'menu', 'menu_id' => '',
    'echo' => true, 'fallback_cb' => 'wp_page_menu', 'before' => '', 'after' => '', 'link_before' => '', 'link_after' => '', 'items_wrap' => '<ul id="%1$s" class="%2$s">%3$s</ul>', 'item_spacing' => 'preserve',
    'depth' => 0, 'walker' => '', 'theme_location' => '' );

    $args = wp_parse_args( $args, $defaults );

    if ( ! in_array( $args['item_spacing'], array( 'preserve', 'discard' ), true ) ) {
        // invalid value, fall back to default.
        $args['item_spacing'] = $defaults['item_spacing'];
    }