SearchWP Regex Whitelist modification to allow strings with letters, numbers, hyphens, underscores, and periods

functions.php

<?php
  function my_searchwp_term_pattern_whitelist( $whitelist ) {
	  $my_whitelist = array(
			"/(\\b[-_.]?[0-9a-zA-Z]+(?:[-_.]+[0-9a-zA-Z]+)+[-_.]?)/iu", // strings with letters, numbers, hyphens, underscores, and periods (no spaces)
		);
	  
	  // we want our pattern to be considered the most specific 
	  // so that false positive matches do not interfere
	  $whitelist = array_merge( $my_whitelist, $whitelist );
	  
	  return $whitelist;
}

add_filter( 'searchwp_term_pattern_whitelist', 'my_searchwp_term_pattern_whitelist' );