anchor.diff:    :MSEC              *milliseconds
     :USEC              *microseconds
     :NSEC              *nanoseconds
  +  :ORDINAL-DAY       day ordinal suffix
     :ISO-WEEK-YEAR     *year for ISO week date (can be different from regular calendar year)
     :ISO-WEEK-NUMBER   *ISO week number (i.e. 1 through 53)
     :ISO-WEEK-DAY      *ISO compatible weekday number (monday=1, sunday=7)
  
positive.code: 
  ;;; Declaims
  
  (declaim (inline now format-timestring %get-current-time
                   format-rfc3339-timestring to-rfc3339-timestring
                   format-rfc1123-timestring to-rfc1123-timestring)
           (ftype (function (&rest t) simple-base-string) format-rfc3339-timestring)
  
negative.code: 
  You can see examples in +ISO-8601-FORMAT+, +ASCTIME-FORMAT+, and +RFC-1123-FORMAT+."
    (declare (type (or boolean stream) destination))
    (let ((result (%construct-timestring timestamp (if (stringp format) (parse-string-format format) format) timezone)))
      (when destination
        (write-string result (if (eq t destination) *standard-output* destination)))
      result))
  
  (define-compiler-macro format-timestring (destination timestamp &key
                                                   (format +iso-8601-format+ format-supplied-p)
                                                   (timezone '*default-timezone*))
    (let ((destination (if (eq t destination) '*standard-output* destination))
          (format (if (stringp format)
                      `(quote ,(parse-string-format format))
                      (if format-supplied-p
                          format
                          `(quote ,format)))))
      (if destination
          `(write-string (%construct-timestring ,timestamp ,format ,timezone) ,destination)
          `(%construct-timestring ,timestamp ,format ,timezone))))
  
  (defun format-rfc1123-timestring (destination timestamp &key
                                    (timezone *default-timezone*))
  