Standard Library
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Package calendar (in calendar.i) -
Index of documented functions or symbols:
DOCUMENT dec = base60(h, m, s)
or base60, h, m, s, dec
converts hours (or degrees) H, minutes M, and seconds S into
decimal hours (or degrees) DEC, in the first form. In the
second form, DEC is the input, and H, M, and S are the outputs
(H and M are whole numbers of type double in that case).
SEE ALSO: unix_time, julian_day, datestamp, base60
DOCUMENT jdn = calendar(y, m, d)
or calendar, y, m, d, jdn
returns the Julian Day Number, JDN, associated with year Y,
month M (1=Jan, 2=Feb, ..., 12=Dec) and day of month D in the
first form. In the second form, JDN is the input, and Y, M,
and D are outputs.
The Julian Day Number is a day count used by astronomers, which
is by definition independent of any calendar; each passing day
increments the count by one. The zero day of the count falls a
bit before 4700 BC, for esoteric reasons (see Wikipedia).
Julian Day Number modulo 7 (JDN%7) is the day of the week, with
0=Mon, 1=Tue, ..., 6=Sun.
By default, Y, M, and D are in the modern Gregorian calendar.
However, with the julian=1 keyword in either form, calendar
treats Y, M, and D as the date in the Julian calendar, used
in Roman Catholic countries before 1582, in the British
empire before 1752, and in Eastern Orthodox countries well
into the twentieth century (again, see Wikipedia).
In the first form (when computing JDN), if Y<50, calendar
assumes 2000+Y, and if 50<=Y<100, calendar assumes 1900+Y,
unless the noabbrev=1 keyword is present, in which case it
assumes you are doing ill-advised archeological work. In
the second form, the output Y will always include the century.
The julian=1 keyword implies noabbrev=1.
SEE ALSO: unix_time, julian_day, datestamp
DOCUMENT ts = datestamp(y, m, d, h)
or datestamp, y, m, d, h, ts
or ts = datestamp(y, m, d, h, 1)
converts numeric year Y, month M, day D, and hour H into the 25
character string format TS returned by the timestamp() function.
The hour H can be a floating point number witha fractional part.
In the second form, returns Y, M, D, and H, given TS.
In the third form, returns Y, M, D, H, and TS for the current
local time, as returned by the timestamp() function.
SEE ALSO: timestamp, unix_time, julian_day, base60, calendar
DOCUMENT jd = julian_day(y, m, d, h)
or julian_day, y, m, d, h, jd
or jd = julian_day(now=1)
converts numeric year Y, month M, day D, and hour H into the
corresponding Julian Day, which includes the fractional part
of the day, measured from noon (not midnight) GMT.
The hour H can be a floating point number with a fractional part.
In the second form, returns Y, M, D, and H, given JD.
In the third form, returns JD for the current time.
This requires calculating your time zone, as noted below.
By default, the input or returned Y, M, D, H represent Greenwich
time (UT). (The UNIX time is, by definition, in the Greenwich
time zone.) However, with the loc=1 keyword in the first two
forms, Y, M, D, H are the local time.
The loc=1 or now=1 keywords require the time zone. If it has not
been previously set, the tz_set function is invoked to set it.
DOCUMENT tz_set
or tz_set, offset
sets the tz_offset global variable, which is the difference
between local time and Greenwich mean time in seconds. In the
second form, you specify the offset directly. In the first form,
tz_set attempts to compute it, either from the UNIX time returned
by the timestamp function, or from the system date utility if
that is not available. If neither of these attempts works,
sets tz_offset to zero.
SEE ALSO: unix_time, julian_day
DOCUMENT t = unix_time(y, m, d, h)
or unix_time, y, m, d, h, t
or t = unix_time(now=1)
converts numeric year Y, month M, day D, and hour H into the
corresponding "UNIX time" T, the number of seconds since
1970 Jan 1 00:00:00 UTC = 2440587.5 JD.
The hour H can be a floating point number with a fractional part.
In the second form, returns Y, M, D, and H, given T.
In the third form, returns T for the current time.
This requires calculating your time zone, as noted below.
By default, the input or returned Y, M, D, H represent Greenwich
time (UT). (The UNIX time is, by definition, in the Greenwich
time zone.) However, with the loc=1 keyword in the first two
forms, Y, M, D, H are the local time.
The loc=1 or now=1 keywords require the time zone. If it has not
been previously set, the tz_set function is invoked to set it.
SEE ALSO: julian_day, calendar, datestamp, base60, tz_set