On Sat, Aug 22, 2015 at 4:36 PM, George Neuner <gneun...@comcast.net> wrote: > > The latter code using date works properly (modulo the time zone field) and > gives consistent results, but the former using date* gives inconsistent > results. > > E.g.,: with timezone = -5 > > => expires #(struct:sql-timestamp 2015 8 22 21 56 33 805346000 0) > => expires #(struct:date* 33 56 21 22 8 2015 6 233 #f 0 805346000 "") > => expires #(struct:date* 58 9 17 22 8 2015 6 233 #f 0 346000000 "UTC") > > => expires #(struct:sql-timestamp 2015 8 22 22 23 45 95751000 0) > => expires #(struct:date* 45 23 22 22 8 2015 6 233 #f 0 95751000 "") > => expires #(struct:date* 20 25 17 22 8 2015 6 233 #f 0 751000000 "UTC") >
These both look wrong to me. Maybe I'm confused, but my understanding is that the database timestamp is in UTC, and you want a date* representing the same point in time, but in specified UTC offset. In other words, Your first example here starts with 2015-08-22T21:56:33.805346Z. Your end result is 2015-08-22T17:09:58.346, which is clearly not exactly 5 hours offset. In the second example, you start with 2015-08-22T22:23:45.95751000Z and wind up with 2015-08-22T17:25:20.751, which is also wrong, but by a considerably smaller margin. I actually can't reproduce the problem in the second example, but I'm also running 6.2.0.2. It looks to me like date->seconds roundtrips correctly w.r.t. seconds->date but date*->seconds does not: ``` > d (date* 33 56 21 22 8 2015 6 233 #f 0 805346000 "") > (seconds->date (+ (* -5 60 60) (date->seconds d #f)) #f) (date* 33 56 16 22 8 2015 6 233 #f 0 0 "UTC") ;; correct, modulo nanoseconds > (seconds->date (+ (* -5 60 60) (date*->seconds d #f)) #f) (date* 58 9 17 22 8 2015 6 233 #f 0 346000000 "UTC") ;; incorrect ``` So, yeah, I'd say that there's a bug in date*->seconds: ``` > (date->seconds d #f) 1440280593 > (date*->seconds d #f) 1440281398 173/500 ``` Let's see what this looks like in gregor's terms: ``` > (define d (moment 2015 8 22 21 56 33 805346000 #:tz "UTC")) > d #<moment 2015-08-22T21:56:33.805346Z[UTC]> > (adjust-timezone d (* -5 60 60)) #<moment 2015-08-22T16:56:33.805346-05:00> > (->posix d) 1440280593 402673/500000 ``` -Jon -- You received this message because you are subscribed to the Google Groups "Racket Users" group. To unsubscribe from this group and stop receiving emails from it, send an email to racket-users+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
