[site-reviews] shortcodes to restrict user content on page

//
// Alternative is to use: https://wordpress.org/plugins/user-access-shortcodes/
//

/**
 * Registers the [is_admin][/is_admin] shortcode
 * This shortcode displays content only to administrator users
 *
 * Example usage: [is_admin][site_reviews_form][/is_admin]
 *
 * Paste this in your active theme's functions.php file
 * @param array $atts
 * @param string $content
 * @return string
 */
add_shortcode('is_admin', function ($atts, $content = '') {
    return (current_user_can('administrator') && !empty($content) && !is_feed())
        ? do_shortcode($content)
        : '';
}, 10, 2);

/**
 * Registers the [is_member][/is_member] shortcode
 * This shortcode displays content only to logged in users
 *
 * Example usage: [is_member][site_reviews_form][/is_member]
 *
 * Paste this in your active theme's functions.php file
 * @param array $atts
 * @param string $content
 * @return string
 */
add_shortcode('is_member', function ($atts, $content = '') {
    return (is_user_logged_in() && !empty($content) && !is_feed())
        ? do_shortcode($content)
        : '';
}, 10, 2);

/**
 * Registers the [is_guest][/is_guest] shortcode
 * This shortcode displays content only to users who are not logged in
 *
 * Example usage: [is_guest][site_reviews_form][/is_guest]
 *
 * Paste this in your active theme's functions.php file
 * @param array $atts
 * @param string $content
 * @return string
 */
add_shortcode('is_guest', function( $atts, $content = '') {
    return ((!is_user_logged_in() && !empty($content)) || is_feed())
        ? do_shortcode($content)
        : '';
}, 10, 2);