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[Chicken-users] Date/time problem (my code I am sure)

From: Jeremy Cowgar
Subject: [Chicken-users] Date/time problem (my code I am sure)
Date: Wed, 20 Dec 2006 22:01:58 -0500
User-agent: Mutt/1.5.13 (2006-08-11)

I have written a few functions to help me in dealing with dates and times.
vector->date was created because postgresql egg returns a vector for the
date. The original (not stripped for including here) supports date, date and
time depending on vector length. to-time was created so I can send a few
different types to my functions, then finally, the source of the problem,
distance-of-time-in-words is a copy of (don't get mad) ruby on rails function
that displays things like "about a minute", "12 days", "13 hours", etc... for
difference. It too has been severly stripped for including here.

My problem is that when I use (currrent-date) the calculation from a date
object using time-difference is **way** off. I am not sure if I am not
creating a date object correctly via (make-date) or what. When I compare two
vectors #(2006 12 10) to say #(2006 12 9) which is converted to a date type
via make-date, that works fine, but comparing a #(2006 12 20) to
(current-date) everything goes wacky.

I have stripped the code to as little as possible to display the problem, can
anyone offer any advice?


(use srfi-19 srfi-19-io)

(define (vector->date vec)
           0 0 0 0
                    (vector-ref vec 2)
                                   (vector-ref vec 1)
                                            (vector-ref vec 0)

(define (to-time obj)
           ((time? obj)   obj)
                    ((date? obj)   (date->time-utc obj))
                                   ((vector? obj) (date->time-utc (vector->date 

(define (distance-of-time-in-words from #!optional (to (current-date)))
  (let* ((from-time (to-time from))
                 (to-time (to-time to))
(time-second (time-difference
from-time to-time))))

(define vec1 (vector 2006 12 20))
(define vec2 (vector 2006 12 19))
(print (distance-of-time-in-words vec1))       ;; 675162109
(print (distance-of-time-in-words vec1 vec2))  ;; 86400


As you can see, the  675162109 number is wacky. That's 7,814 days. In order
for this sample to work, you need to chicken-setup srfi-19 to get the
date/time stuff.

Oh, again, realize that these functiosn in my code do much more than
presented here, i.e. the distance-of-time-in-words is useless basically in
this example, but the real function continues much beyond the current
example, just trimed for ease of finding the problem.

Thanks for any help!


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