(defpackage :prune-datelist
   (:use :cl :alexandria :serapeum :fw.lu)
   (:export #:main
            #:prune-datelist))
 (in-package :prune-datelist)
 
 (defun mappend-history (fun list)
   (loop
      for prev = nil then (cons cur prev)
      for cur on list
      append (funcall fun prev (car cur) (cdr cur))))
 
 (defun map-longest ()
   remove-from-plist)
 
 (defun prune-datelist (dates period)
   (let ((parsed-dates (mapcar (op (local-time:parse-timestring _))
                               dates)))
     ()))
 
 (defun main (args)
   )