Localizes list items before the rest of the content.

The ‘%l’ must be at the first characters can then contain the rest of the
content. The list items will have ‘, ‘, ‘, and’, and ‘ and ‘ added depending
on the amount of list items in the $args parameter.

function wp_sprintf_l( $pattern, $args ) {
	// Not a match.
	if ( '%l' !== substr( $pattern, 0, 2 ) ) {
		return $pattern;
	}

	// Nothing to work with.
	if ( empty( $args ) ) {
		return '';
	}

	/**
	 * Filters the translated delimiters used by wp_sprintf_l().
	 * Placeholders (%s) are included to assist translators and then
	 * removed before the array of strings reaches the filter.
	 *
	 * Please note: Ampersands and entities should be avoided here.
	 *
	 * @since 2.5.0
	 *
	 * @param array $delimiters An array of translated delimiters.
	 */
	$l = apply_filters(
		'wp_sprintf_l',
		array(
			/* translators: Used to join items in a list with more than 2 items. */
			'between'          => sprintf( __( '%1$s, %2$s' ), '', '' ),
			/* translators: Used to join last two items in a list with more than 2 times. */
			'between_last_two' => sprintf( __( '%1$s, and %2$s' ), '', '' ),
			/* translators: Used to join items in a list with only 2 items. */
			'between_only_two' => sprintf( __( '%1$s and %2$s' ), '', '' ),
		)
	);

	$args   = (array) $args;
	$result = array_shift( $args );
	if ( count( $args ) == 1 ) {
		$result .= $l['between_only_two'] . array_shift( $args );
	}

	// Loop when more than two args.
	$i = count( $args );
	while ( $i ) {
		$arg = array_shift( $args );
		$i--;
		if ( 0 == $i ) {
			$result .= $l['between_last_two'] . $arg;
		} else {
			$result .= $l['between'] . $arg;
		}
	}

	return $result . substr( $pattern, 2 );
}