4 Combined Date and Time

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datetime

datetime?

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4Combined Date and Time🔗 i

The datetime struct represents the combination of a date and a time ; that is, it represents a date at a particular time-of-day. However, it does not include time zone information, so it does not represent an absolute moment in time.

procedure
( datetime year
[ month
day
hour
minute
second
nanosecond]) → datetime?
year:exact-integer?
month:(integer-in 112)=1
day:(day-of-month/c yearmonth)=1
hour:(integer-in 023)=0
minute:(integer-in 059)=0
second:(integer-in 059)=0
nanosecond:(integer-in 0999999999)=0

Constructs a datetime with the given date and time fields.

Examples:

> (datetime 1970)

#<datetime 1970年01月01日T00:00:00>
> (datetime 1969721256)

#<datetime 1969年07月21日T02:56:00>

procedure
( datetime? x)→boolean?
x:any/c

Returns #t if x is a datetime ; #f otherwise.

procedure
( jd->datetime jd)→datetime?
jd:real?

Returns the datetime corresponding to the given Julian day, which is the number of solar days that have elapsed since 12:00 UT on November 24, 4714 BC in the proleptic Gregorian calendar.

Examples:

> (jd->datetime 0)

#<datetime -4713年11月24日T12:00:00>
> (jd->datetime 2440587.5)

#<datetime 1970年01月01日T00:00:00>

procedure
( posix->datetime posix)→datetime?
posix:real?

Returns the datetime corresponding to the given POSIX time, which is the number of seconds that have elapsed since 00:00 UTC on January 1, 1970.

Examples:

> (posix->datetime 0)

#<datetime 1970年01月01日T00:00:00>
> (posix->datetime 2147483648)

#<datetime 2038年01月19日T03:14:08>

procedure
( datetime->iso8601 dt)→string?
dt:datetime?

Returns an ISO 8601 string representation of dt.

Examples:

> (datetime->iso8601 (datetime 1970))

"1970-01-01T00:00:00"
> (datetime->iso8601 (datetime 1969721256))

"1969-07-21T02:56:00"
> (datetime->iso8601 (datetime 1234567))

"0001-02-03T04:05:06.000000007"

procedure
( datetime=? xy)→boolean?
x:datetime?
y:datetime?

procedure
( datetime<? xy)→boolean?
x:datetime?
y:datetime?

procedure
( datetime<=? xy)→boolean?
x:datetime?
y:datetime?

procedure
( datetime>? xy)→boolean?
x:datetime?
y:datetime?

procedure
( datetime>=? xy)→boolean?
x:datetime?
y:datetime?

Comparison functions on datetimes.

Examples:

> (datetime=? (datetime 197011)(datetime 1970))

#t
> (datetime<? (datetime 1970)(datetime 1969721256))

#f
> (datetime>? (datetime 1970)(datetime 1969721256))

#t

value
datetime-order :order?

An order defined on datetimes.

Examples:

> (datetime-order (datetime 197011)(datetime 1970))

'=
> (datetime-order (datetime 1970)(datetime 1969721256))

'>
> (datetime-order (datetime 1969721256)(datetime 1970))

'<
> (make-splay-tree datetime-order )

#<splay-tree*>

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