https://github.com/wojtekmach/calendar_interval
Functions for working with calendar intervals
https://github.com/wojtekmach/calendar_interval
Last synced: 7 months ago
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Functions for working with calendar intervals
- Host: GitHub
- URL: https://github.com/wojtekmach/calendar_interval
- Owner: wojtekmach
- License: other
- Created: 2018-02-03T09:44:29.000Z (over 7 years ago)
- Default Branch: master
- Last Pushed: 2020-07-12T11:36:05.000Z (about 5 years ago)
- Last Synced: 2025-03-14T18:51:03.855Z (7 months ago)
- Language: Elixir
- Homepage:
- Size: 146 KB
- Stars: 71
- Watchers: 4
- Forks: 3
- Open Issues: 10
-
Metadata Files:
- Readme: README.md
- Changelog: CHANGELOG.md
- License: LICENSE.md
Awesome Lists containing this project
README
# CalendarInterval
[](https://travis-ci.org/wojtekmach/calendar_interval)
Functions for working with calendar intervals.
Key ideas:
* Time is enumerable: "2018" is a collection of "2018-01/2018-12" months, "2018-01-01/2018-12-31" days etc
* Everything is an interval: "2018" is an interval of 1 year, or 12 months, or 365 days etc.
A timestamp with microsecond precision is an interval 1 microsecond long
* Allen's Interval Algebra: formalism for relations between time intervals
## Examples
```elixir
use CalendarInterval
iex> ~I"2018-06".precision
:month
iex> CalendarInterval.next(~I"2018-12-31")
~I"2019-01-01"
iex> CalendarInterval.nest(~I"2018-06-15", :minute)
~I"2018-06-15 00:00/23:59"
iex> CalendarInterval.relation(~I"2018-01", ~I"2018-02/12")
:meets
iex> Enum.count(~I"2016-01-01/12-31")
366
```
## References
This library is heavily inspired by "Exploring Time" talk by Eric Evans [1] where
he mentioned the concept of "Countable Time" and introduced me to
"Allen's Interval Algebra" [2].
- [1]
- [2]
I've also given a talk about some of these ideas at Empex NYC 2018:
[video](https://www.youtube.com/watch?v=vUOA5GgYg9I),
[slides](https://speakerdeck.com/wojtekmach/recurrences-and-intervals).
## Installation
Add to `mix.exs`:
```elixir
def deps do
[
{:calendar_interval, "~> 0.2.0"}
]
end
```
## License
[Apache 2.0](./LICENSE.md)