10 releases
| 0.1.5 | Mar 11, 2022 |
|---|---|
| 0.1.4 | Sep 17, 2020 |
| 0.1.3 | Jul 1, 2020 |
| 0.1.2 | May 3, 2019 |
| 0.0.1 | Sep 11, 2016 |
#208 in Date and time
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Used in fluxcap
345KB
1.5K
SLoC
Documentation
Kronos is a tool for calculating date/times. It is meant to give a concrete date for questions like "When is the 2nd Monday of June?", or "What was the 3rd to last day-of-the-week of past February?".
To answer these questions kronos composes TimeSequence iterators. These are infinite sequences into the past and the future which you can pin to a particular instant and get resulting time Ranges.
Example
Lets first define a TimeSequence that represents any and all Mondays. Then use it to get an iterator of all future Mondays from a specific t0 instant onward.
// Reference time: Tuesday, 5th Feb 2019
let t0 = chrono::NaiveDate::from_ymd(2019, 2, 5)
.and_hms(0, 0, 0);
// A sequence for *Mondays*
let mondays = kronos::Weekday(1);
// First Monday after t0 reference time
mondays.future(&t0).next()
Ranges
The previous example would return a Range which represents an open-ended time interval [start, end). Ranges also have a Grain that specifies the resolution of the start and end instants.
Examples of a Range could be Aug 26th 2018.
- It has a resolution of Grain::Day,
- starts on 2018/08/26 00:00:00,
- ends on 2018/08/27 00:00:00
Composing TimeSequences
Basic sequences
Some simple TimeSequences can be built almost out of thin air. For example:
Weekday(2)a sequence for Tuesdays.Month(6)a sequence for all June months.Grains(Grain::Day)a sequence to iterate over days.
Composite sequences
More comples TimeSequences can be created by combining other sequences. For example:
NthOf(2, Weekday(1), Month(6))creates a sequence for "the second Mondays of June".LastOf(1, Weekend, Grains(Grain::Year))for "last weekend of the year".Intersect(Weekday(1), NthOf(28, Grains(Grain::Day), Grains(Grains::Month)))for "all Monday 28th".
Other compositions allow unions, intersections, intervals, exceptions, etc. Please check each module's tests for examples on how to use them.
References
Dependencies
~1MB
~18K SLoC