original_string: public static function is_email($email): bool
    {
      if ( function_exists('filter_var') ){
        return filter_var($email,FILTER_VALIDATE_EMAIL) ? true : false;
      }
      else
      {
        $isValid = true;
        $atIndex = mb_strrpos($email, "@");
        if (\is_bool($atIndex) && !$atIndex)
        {
          $isValid = false;
        }
        else
        {
          $domain = mb_substr($email, $atIndex+1);
          $local = mb_substr($email, 0, $atIndex);
          $localLen = mb_strlen($local);
          $domainLen = mb_strlen($domain);
          //  local part length exceeded
          if ($localLen < 1 || $localLen > 64)
            $isValid = false;
          //  domain part length exceeded
          else if ($domainLen < 1 || $domainLen > 255)
            $isValid = false;
          // local part starts or ends with '.'
          else if ($local[0] == '.' || $local[$localLen-1] == '.')
            $isValid = false;
          // local part has two consecutive dots
          else if (mb_ereg_match('\\.\\.', $local))
            $isValid = false;
          // character not valid in domain part
          else if (!mb_ereg_match('^[A-Za-z0-9\\-\\.]+$', $domain))
            $isValid = false;
          //  domain part has two consecutive dots
          else if (mb_ereg_match('\\.\\.', $domain))
            $isValid = false;
          //  character not valid in local part unless
          else if ( !mb_ereg_match('^(\\\\.|[A-Za-z0-9!#%&`_=\\/$\'*+?^{}|~.-])+$'
            ,str_replace("\\\\","",$local)))
          {
            // local part is quoted
            if ( !mb_ereg_match('^"(\\\\"|[^"])+"$',str_replace("\\\\","",$local)) )
              $isValid = false;
          }
        }
        return $isValid;
      }
    }
code: public static function is_email($email): bool
    {
      if ( function_exists('filter_var') ){
        return filter_var($email,FILTER_VALIDATE_EMAIL) ? true : false;
      }
      else
      {
        $isValid = true;
        $atIndex = mb_strrpos($email, "@");
        if (\is_bool($atIndex) && !$atIndex)
        {
          $isValid = false;
        }
        else
        {
          $domain = mb_substr($email, $atIndex+1);
          $local = mb_substr($email, 0, $atIndex);
          $localLen = mb_strlen($local);
          $domainLen = mb_strlen($domain);
          //  local part length exceeded
          if ($localLen < 1 || $localLen > 64)
            $isValid = false;
          //  domain part length exceeded
          else if ($domainLen < 1 || $domainLen > 255)
            $isValid = false;
          // local part starts or ends with '.'
          else if ($local[0] == '.' || $local[$localLen-1] == '.')
            $isValid = false;
          // local part has two consecutive dots
          else if (mb_ereg_match('\\.\\.', $local))
            $isValid = false;
          // character not valid in domain part
          else if (!mb_ereg_match('^[A-Za-z0-9\\-\\.]+$', $domain))
            $isValid = false;
          //  domain part has two consecutive dots
          else if (mb_ereg_match('\\.\\.', $domain))
            $isValid = false;
          //  character not valid in local part unless
          else if ( !mb_ereg_match('^(\\\\.|[A-Za-z0-9!#%&`_=\\/$\'*+?^{}|~.-])+$'
            ,str_replace("\\\\","",$local)))
          {
            // local part is quoted
            if ( !mb_ereg_match('^"(\\\\"|[^"])+"$',str_replace("\\\\","",$local)) )
              $isValid = false;
          }
        }
        return $isValid;
      }
    }
code_tokens: public static function is_email ( $ email ) : bool { if ( function_exists ( 'filter_var' ) ) { return filter_var ( $ email , FILTER_VALIDATE_EMAIL ) ? true : false ; } else { $ isValid = true ; $ atIndex = mb_strrpos ( $ email , "@" ) ; if ( \ is_bool ( $ atIndex ) && ! $ atIndex ) { $ isValid = false ; } else { $ domain = mb_substr ( $ email , $ atIndex + 1 ) ; $ local = mb_substr ( $ email , 0 , $ atIndex ) ; $ localLen = mb_strlen ( $ local ) ; $ domainLen = mb_strlen ( $ domain ) ; //  local part length exceeded if ( $ localLen < 1 || $ localLen > 64 ) $ isValid = false ; //  domain part length exceeded else if ( $ domainLen < 1 || $ domainLen > 255 ) $ isValid = false ; // local part starts or ends with '.' else if ( $ local [ 0 ] == '.' || $ local [ $ localLen - 1 ] == '.' ) $ isValid = false ; // local part has two consecutive dots else if ( mb_ereg_match ( '\\.\\.' , $ local ) ) $ isValid = false ; // character not valid in domain part else if ( ! mb_ereg_match ( '^[A-Za-z0-9\\-\\.]+$' , $ domain ) ) $ isValid = false ; //  domain part has two consecutive dots else if ( mb_ereg_match ( '\\.\\.' , $ domain ) ) $ isValid = false ; //  character not valid in local part unless else if ( ! mb_ereg_match ( '^(\\\\.|[A-Za-z0-9!#%&`_=\\/$\'*+?^{}|~.-])+$' , str_replace ( "\\\\" , "" , $ local ) ) ) { // local part is quoted if ( ! mb_ereg_match ( '^"(\\\\"|[^"])+"$' , str_replace ( "\\\\" , "" , $ local ) ) ) $ isValid = false ; } } return $ isValid ; } }
docstring: Checks if the string is the correct type of e-mail address.
  
  ```php
  \bbn\x::dump(\bbn\str::is_email('test@email.com'));
  // (bool) true
  \bbn\x::dump(\bbn\str::is_email('test@email'));
  // (bool) false
  \bbn\x::dump(\bbn\str::is_email('test@.com'));
  // (bool) false
  \bbn\x::dump(\bbn\str::is_email('testemail.com'));
  // (bool) false
  ```
  
  @param string $email E-mail address.
  @return bool
docstring_tokens: Checks if the string is the correct type of e - mail address .