value gen:datetime-provider : any/c

In fact, gen:datetime-provider is also implemented by date, which can be treated like a datetime with its time component set to midnight. This should be considered an experimental part of the design, which may be removed.

procedure (datetime-provider? x) → boolean?

x : any/c

procedure (->datetime/local t) → datetime?

t : datetime-provider?

> (->datetime/local (datetime 1969 7 21 2 56))

#<datetime 1969-07-21T02:56:00>

> (->datetime/local (moment 2015 3 8 1 #:tz "America/New_York"))

#<datetime 2015-03-08T01:00:00>

procedure (->datetime/utc t) → datetime?

t : datetime-provider?

> (->datetime/utc (datetime 1969 7 21 2 56))

#<datetime 1969-07-21T02:56:00>

> (->datetime/utc (moment 2015 3 8 1 #:tz "America/New_York"))

#<datetime 2015-03-08T06:00:00>

procedure (->posix t) → rational?

t : datetime-provider?

> (->posix (datetime 1970))

0

> (->posix (moment 2015 3 8 1 #:tz "America/New_York"))

1425794400

procedure (->jd t) → rational?

t : datetime-provider?

> (->jd (moment -4713 11 24 12 #:tz "Etc/UTC"))

0

> (->jd (datetime 1970))

4881175/2

procedure (years-between t1 t2) → exact-integer?   t1 : datetime-provider?   t2 : datetime-provider?

procedure (months-between t1 t2) → exact-integer?   t1 : datetime-provider?   t2 : datetime-provider?

procedure (weeks-between t1 t2) → exact-integer?   t1 : datetime-provider?   t2 : datetime-provider?

procedure (days-between t1 t2) → exact-integer?   t1 : datetime-provider?   t2 : datetime-provider?

procedure (hours-between t1 t2) → exact-integer?   t1 : datetime-provider?   t2 : datetime-provider?

procedure (minutes-between t1 t2) → exact-integer?   t1 : datetime-provider?   t2 : datetime-provider?

procedure (seconds-between t1 t2) → exact-integer?   t1 : datetime-provider?   t2 : datetime-provider?

procedure (milliseconds-between t1 t2) → exact-integer?   t1 : datetime-provider?   t2 : datetime-provider?

procedure (microseconds-between t1 t2) → exact-integer?   t1 : datetime-provider?   t2 : datetime-provider?

procedure (nanoseconds-between t1 t2) → exact-integer?   t1 : datetime-provider?   t2 : datetime-provider?

> (years-between (datetime 2000) (datetime 2001))
1
> (years-between (datetime 2001) (datetime 2002))
1
> (months-between (datetime 2000 3) (datetime 1999 12))
-3
> (days-between (moment 2015 3 8  1 59 #:tz "America/Los_Angeles")                 (moment 2015 3 16 1 59 #:tz "America/Los_Angeles"))
8
> (weeks-between (moment 2015 3 8  1 59 #:tz "America/Los_Angeles")                  (moment 2015 3 16 1 59 #:tz "Etc/UTC"))
1
> (days-between (datetime 2015) (datetime 2015 1 14 23 59 59))
13
> (hours-between (moment 2000 #:tz "Etc/UTC")                  (moment 1999 12 31 19 #:tz "America/New_York"))
0
> (minutes-between (datetime 2000) (datetime 2000 1 2))
1440
> (seconds-between (datetime 2000) (datetime 2000 1 2))
86400
> (milliseconds-between (datetime 2000) (datetime 2000 1 2))
86400000
> (microseconds-between (datetime 2000) (datetime 2000 1 2))
86400000000
> (nanoseconds-between (datetime 2000) (datetime 2000 1 2))
86400000000000

procedure (with-timezone   t       tz       #:resolve-offset resolve-offset)

→ timezone-provider?

t : datetime-provider?

tz : tz/c

resolve-offset : offset-resolver/c

This function is a blunt instrument and is rarely needed. If your aim is to translate a moment into another that represents the same point in absolute time but in a different time zone, then you’re looking for adjust-timezone.

> (with-timezone (datetime 2000) "America/New_York")

#<moment 2000-01-01T00:00:00-05:00[America/New_York]>

> (with-timezone (moment 2000 #:tz "America/New_York") "Europe/Paris")

#<moment 2000-01-01T00:00:00+01:00[Europe/Paris]>