( $str, $pos, $span ) ) );
						$pos     += $span;
						break;
					}

					throw new Exception( sprintf( 'Unknown symbol "%s"', $next ) );
			}
		}

		while ( ! empty( $stack ) ) {
			$o2 = array_pop( $stack );
			if ( '(' === $o2 || ')' === $o2 ) {
				throw new Exception( 'Mismatched parentheses' );
			}

			$output[] = array( 'op', $o2 );
		}

		$this->tokens = $output;
	}

	/**
	 * Get the plural form for a number.
	 *
	 * Caches the value for repeated calls.
	 *
	 * @since 4.9.0
	 *
	 * @param int $num Number to get plural form for.
	 * @return int Plural form value.
	 */
	public function get( $num ) {
		if ( isset( $this->cache[ $num ] ) ) {
			return $this->cache[ $num ];
		}
		$this->cache[ $num ] = $this->execute( $num );
		return $this->cache[ $num ];
	}

	/**
	 * Execute the plural form function.
	 *
	 * @since 4.9.0
	 *
	 * @param int $n Variable "n" to substitute.
	 * @return int Plural form value.
	 */
	public function execute( $n ) {
		$stack = array();
		$i     = 0;
		$total = count( $this->tokens );
		while ( $i < $total ) {
			$next = $this->tokens[ $i ];
			$i++;
			if ( 'var' === $next[0] ) {
				$stack[] = $n;
				continue;
			} elseif ( 'value' === $next[0] ) {
				$stack[] = $next[1];
				continue;
			}

			// Only operators left.
			switch ( $next[1] ) {
				case '%':
					$v2      = array_pop( $stack );
					$v1      = array_pop( $stack );
					$stack[] = $v1 % $v2;
					break;

				case '||':
					$v2      = array_pop( $stack );
					$v1      = array_pop( $stack );
					$stack[] = $v1 || $v2;
					break;

				case '&&':
					$v2      = array_pop( $stack );
					$v1      = array_pop( $stack );
					$stack[] = $v1 && $v2;
					break;

				case '<':
					$v2      = array_pop( $stack );
					$v1      = array_pop( $stack );
					$stack[] = $v1 < $v2;
					break;

				case '<=':
					$v2      = array_pop( $stack );
					$v1      = array_pop( $stack );
					$stack[] = $v1 <= $v2;
					break;

				case '>':
					$v2      = array_pop( $stack );
					$v1      = array_pop( $stack );
					$stack[] = $v1 > $v2;
					break;

				case '>=':
					$v2      = array_pop( $stack );
					$v1      = array_pop( $stack );
					$stack[] = $v1 >= $v2;
					break;

				case '!=':
					$v2      = array_pop( $stack );
					$v1      = array_pop( $stack );
					$stack[] = $v1 != $v2;
					break;

				case '==':
					$v2      = array_pop( $stack );
					$v1      = array_pop( $stack );
					$stack[] = $v1 == $v2;
					break;

				case '?:':
					$v3      = array_pop( $stack );
					$v2      = array_pop( $stack );
					$v1      = array_pop( $stack );
					$stack[] = $v1 ? $v2 : $v3;
					break;

				default:
					throw new Exception( sprintf( 'Unknown operator "%s"', $next[1] ) );
			}
		}

		if ( count( $stack ) !== 1 ) {
			throw new Exception( 'Too many values remaining on the stack' );
		}

		return (int) $stack[0];
	}
}
и       р      ffffttie Ѓ±     шэ±     and' conjunction becomes 'Sullie, Pattie and me'.
 * [ 'Sullie', 'Pattie', 'me' ] with 'or' conjunction becomes 'Sullie, Pattie or me'.
 *
 * @since 1.8.0
 *
 * @param array  $list        A list of words or phrases to link together.
 * @param string $conjunction Coordinating conjunction to use for last word or phrase (usually вЂ“ and, or).
 *                            The string is expected to be translatable.
 *
 * @return string Linked words and/or phrases.
 */
function wpforms_conjunct( $list, $conjunction ) {

	$last_chunk = array_pop( $list );

	return $list ?
		sprintf( '%s %s %s', implode( ', ', $list ), $conjunction, $last_chunk ) :
		$last_chunk;
}

/**
 * Get the current URL.
 *
 * @since 1.0.0
 * @since 1.7.2 Refactored based on the `home_url` function.
 *
 * @return string
 */
function wpforms_current_url() {

	$parsed_home_url = wp_parse_url( home_url() );

	$url = $parsed_home_url['scheme'] . '://' . $parsed_home_url['host'];

	if ( ! empty( $parsed_home_url['port'] ) ) {
		$url .= ':' . $parsed_home_url['port'];
	}

	// phpcs:ignore WordPress.Security.ValidatedSanitizedInput.InputNotValidated, WordPress.Security.ValidatedSanitizedInput.InputNotSanitized
	$url .= wp_unslash( $_SERVER['REQUEST_URI'] );

	return esc_url_raw( $url );
}

/**
 * Add UTM tags to a link that allows detecting traffic sources for our or partners' websites.
 *
 * @since 1.7.5
 *
 * @param string $link    Link to which you need to add UTM tags.
 * @param string $medium  The page or location description. Check your current page and try to find
 *                        and use an already existing medium for links otherwise, use a page name.
 * @param string $content The feature's name, the button's content, the link's text, or something
 *                        else that describes the element that contains the link.
 * @param string $term    Additional information for the content that makes the link more unique.
 *
 * @return string
 */
function wpforms_utm_link( $link, $medium, $content = '', $term = '' ) {

р      add_query_arg(
		array_filter(
			[
				'utm_campaign' => wpforms()->is_pro() ? 'plugin' : 'liteplugin',
				'utm_source'   => strpos( $link, 'https://wpforms.com' ) === 0 ? 'WordPress' : 'wpformsplugin',
				'utm_medium'   => rawurlencode( $medium ),
				'utm_content'  => rawurlencode( $content ),
				'utm_term'     => rawurlencode( $term ),
				'utm_locale'   => wpforms_sanitize_key( get_locale() ),
			]
		),
		$link
	);
}

/**
 * Modify the default USer-Agent generated by wp_remote_*() to include additional information.
 *
 * @since 1.7.5.2
 *
 * @return string
 */
function wpforms_get_default_user_agent() {

	$license_type = wpforms()->is_pro() ? ucwords( (string) wpforms_get_license_type() ) : 'Lite';

	return 'WordPress/' . get_bloginfo( 'version' ) . '; ' . get_bloginfo( 'url' ) . '; WPForms/' . $license_type . '-' . WPFORMS_VERSION;
}

/**
 * Get the ISO 639-2 Language Code from user/site locale.
 *
 * @see http://www.loc.gov/standards/iso639-2/php/code_list.php
 *
 * @since 1.5.0
 *
 * @return string
 */
function wpforms_get_language_code() {

	$default_lang = 'en';
	$locale       = get_user_locale();

	if ( ! empty( $locale ) ) {
		$lang = explode( '_', $locale );

		if ( ! empty( $lang ) && is_array( $lang ) ) {
			$default_lang = strtolower( $lang[0] );
		}
	}

	return $default_lang;
}

/**
 * Changes array of items into string of items, separated by comma and sql-escaped.
 *
 * @see https://coderwall.com/p/zepnaw
 *
 * @since 1.7.4
 *
 * @param mixed|array $items  Item(s) to be joined into string.
 * @param string      $format Can be %s or %d.
 *
 * @return string Items separated by comma and sql-escaped.
 */
function wpforms_wpdb_prepare_in( $items, $format = '%s' ) {

	global $wpdb;

	$items    = (array) $items;
	$how_many = count( $items );

	if ( $how_many === 0 ) {
		return '';
	}

	$placeholders    = array_fill( 0, $how_many, $format );
	$prepared_format = implode( ',', $placeholders );

	// phpcs:ignore WordPress.DB.PreparedSQL.NotPrepared
	return $wpdb->prepare( $prepared_format, $items );
}

/**
 * Get the render engine slug according to the Modern Markup setting value and corresponding filter.
 *
 * @since 1.8.1
 *
 * @return string
 */
function wpforms_get_render_engine() {

	$render_engine = empty( wpforms_setting( 'modern-markup', false ) ) ? 'classic' : 'modern';

	/**
	 * Filter current render engine slug.
	 * Allows addons to use their own frontend rendering engine.
	 *
	 * @since 1.8.1
	 *
	 * @param string $render_engine Render engine slug.
	 */
	$render_engine = apply_filters( 'wpforms_get_render_engine', $render_engine );

	return $render_engine;
}