php - Call to undefined function create_function()

I get this message on the front page of my website:

Fatal error: Uncaught Error: Call to undefined function create_function() in /customers/7/e/7/jovobytes.be/httpd.www/wp-content/themes/inovado/framework/inc/widgets/custommenu.php:67 Stack trace: #0 /customers/7/e/7/jovobytes.be/httpd.www/wp-content/themes/inovado/functions.php(39): include_once() #1 /customers/7/e/7/jovobytes.be/httpd.www/wp-settings.php(566): include('/customers/7/e/...') #2 /customers/7/e/7/jovobytes.be/httpd.www/wp-config.php(96): require_once('/customers/7/e/...') #3 /customers/7/e/7/jovobytes.be/httpd.www/wp-load.php(50): require_once('/customers/7/e/...') #4 /customers/7/e/7/jovobytes.be/httpd.www/wp-blog-header.php(13): require_once('/customers/7/e/...') #5 /customers/7/e/7/jovobytes.be/httpd.www/index.php(17): require('/customers/7/e/...') #6 {main} thrown in /customers/7/e/7/jovobytes.be/httpd.www/wp-content/themes/inovado/framework/inc/widgets/custommenu.php on line 67

so i looked up the corresponding file of the theme and need to rewrite the code so it's compatible with php 8.0. Any help would be appreceated !!!

<?php


class WP_Nav_Menu_Widget_Desc extends WP_Widget {

    function __construct() {
        parent::WP_Widget(false, 'minti.SideNav', array('description' => 'Display a Side Navigation'));

    }

    function widget($args, $instance) {
        // Get menu
        $nav_menu = wp_get_nav_menu_object( $instance['nav_menu'] );

        if ( !$nav_menu )
            return;

        echo $args['before_widget'];

        //if ( !empty($instance['title']) )
        //  echo $args['before_title'] . $instance['title'] . $args['after_title'];

        wp_nav_menu( array( 'depth' => 1, 'menu' => $nav_menu ) );

        echo $args['after_widget'];
    }

    function update( $new_instance, $old_instance ) {
        $instance['nav_menu'] = (int) $new_instance['nav_menu'];
        return $instance;
    }

    function form( $instance ) {
        $nav_menu = isset( $instance['nav_menu'] ) ? $instance['nav_menu'] : '';

        // Get menus
        $menus = get_terms( 'nav_menu', array( 'hide_empty' => false ) );

        // If no menus exists, direct the user to go and create some.
        if ( !$menus ) {
            echo '<p>'. sprintf( __('No menus have been created yet. <a href="%s">Create some</a>.'), admin_url('nav-menus.php') ) .'</p>';
            return;
        }
        ?>
        <p>
            <label for="<?php echo $this->get_field_id('nav_menu'); ?>"><?php _e('Select Menu:'); ?></label>
            <select id="<?php echo $this->get_field_id('nav_menu'); ?>" name="<?php echo $this->get_field_name('nav_menu'); ?>">
        <?php
            foreach ( $menus as $menu ) {
                $selected = $nav_menu == $menu->term_id ? ' selected="selected"' : '';
                echo '<option'. $selected .' value="'. $menu->term_id .'">'. $menu->name .'</option>';
            }
        ?>
            </select>
        </p>
        <?php
    }
}
add_action('widgets_init', create_function('', 'return register_widget("WP_Nav_Menu_Widget_Desc");'));
?>

Solution:

That very specific action can be rewritten as:

add_action(
    'widgets_init',
    function() {
        register_widget("WP_Nav_Menu_Widget_Desc");
    }
);

However, the widget itself uses the older style constructor syntax, so that needs to be changed, too.

class WP_Nav_Menu_Widget_Desc extends WP_Widget {

    function __construct() {
        parent::__construct(false, 'minti.SideNav', array('description' => 'Display a Side Navigation'));
    }
}

Its been a while since I've seen that constructor syntax, so I wouldn't be surprised if more of this code is broken, too. You really should consider either upgrading the theme/plugin to a newer version, or not upgrading your PHP version

Solution:

My solution:

if (!function_exists('create_function')) 
{
  $FAUTO_NUM=1; 
  function create_function($pars, $code)
  { global $FAUTO_NUM;
    $FAUTO_NUM++;  
    $fid=$FAUTO_NUM; 
    $str="function fauto$fid($pars) { $code };"; 
    eval($str);
    return "fauto".$fid; 
  }; 
};