Time spans are a time duration in some time scale represented as a ddoublestd/num/ddouble/ddouble: V; this gives it very high precision and range to represent time very precisely. (see the instant module).

A time stamp denotes an instant in time since 2000-01-01 in some time scale. Time stamps also keep track of possible leap seconds for UTC based timescales. Unix/UTC seconds.

• One way is as a duration in TAI SI seconds but that would lead to many unnecessary conversions (and loss of precision), for example for unix timestamps that need adjustments for leap seconds.
• To avoid conversions, it is better to represent as days plus the seconds into that day. However, that means that adding or subtracting seconds always needs normalization.
• To make it easier to add/substract time spans, we can represent it as single timespan since where daysstd/time/timestamp/days: (ts : timestamp) -> int == floor(since / 86400) and seconds == since - daysstd/time/timestamp/days: (ts : timestamp) -> int. This is essentially the representation that Unix/Posic timestamps use too.
• Finally, we add a separate leapstd/time/timestamp/leap: (t : timestamp) -> int seconds field to represent time in a leap step unambigiously (and also at any time during the day). The leapstd/time/timestamp/leap: (t : timestamp) -> int field is positive if this time is in a leap step.

Here is the representation of a time in the leap second just before 2006-01-01:

time(2005,12,31,23,59,60,0.5).instant.timestamp.ts-show == "189388799.500 (+1 leap)"
time(2005,12,31,23,59,60,0.5).instant.timestamp.ts-show-days == "2191d 86399.500s (+1 leap)"
time(2005,12,31,23,59,60,0.5).instant.timestamp.ts-showstd/time/timestamp/ts-show: (ts : timestamp, max-prec : ? int, secs-width : ? int, unit : ? string) -> string == "189388799.500 (+1 leap)"
time(2005,12,31,23,59,60,0.5).instant.timestamp.ts-show-daysstd/time/timestamp/ts-show-days: (ts : timestamp, prec : ? int) -> string == "2191d 86399.500s (+1 leap)"

The leapstd/time/timestamp/leap: (t : timestamp) -> int field also lets us represent leap times that occurred at another time than the last second of the day:

time(1959,1,28,18,59,59,0.01).instant.timestamp.ts-show-days == "-14948d 68399.010s"
time(1959,1,28,18,59,60,0.01).instant.timestamp.ts-show-days == "-14948d 68399.010s (+1 leap)"
time(1959,1,28,19, 0, 0,0.01).instant.timestamp.ts-show-days == "-14948d 68400.010s"
time(1959,1,28,18,59,59,0.01).instant.timestamp.ts-show-daysstd/time/timestamp/ts-show-days: (ts : timestamp, prec : ? int) -> string == "-14948d 68399.010s"
time(1959,1,28,18,59,60,0.01).instant.timestamp.ts-show-daysstd/time/timestamp/ts-show-days: (ts : timestamp, prec : ? int) -> string == "-14948d 68399.010s (+1 leap)"
time(1959,1,28,19, 0, 0,0.01).instant.timestamp.ts-show-daysstd/time/timestamp/ts-show-days: (ts : timestamp, prec : ? int) -> string == "-14948d 68400.010s"

See utc for more information on leap seconds.

Timespan from a ddoublestd/num/ddouble/ddouble: V. Just for convenience as timespanstd/time/timestamp/timespan: V is an alias.

Divide using divstd/time/timestamp/div: (x : timespan, y : timespan, prec : ? int) -> timespan to allow for different timespan representations.

Seconds in a solar day, 86400.

A zero-valued timespan.