anchor.diff:             #:encode-local-time
              #:decode-local-time
              #:parse-timestring
  +           #:parse-datestring
              #:format-timestring
              #:format-rfc3339-timestring
              #:parse-rfc3339-timestring
  
positive.code:       (unless year (setf year 2000))
        (encode-local-time usec second minute hour day month year :timezone timezone))))
  
  (defun format-rfc3339-timestring (local-time &rest args &key omit-date-part-p omit-time-part-p
                                               omit-timezone-part-p &allow-other-keys)
    (declare (ignore omit-date-part-p omit-time-part-p omit-timezone-part-p))
  
negative.code:                         :usec usec
                          :timezone (realize-timezone
                                     (or timezone *default-timezone*)))))))
  
  (defun today ()
    (minimize-time-part (now) :timezone +utc-zone+))
  
  (defun now ()
    (local-time :universal (get-universal-time)))
  