interval

# Interval

[![CI](https://github.com/tbug/elixir_interval/actions/workflows/ci.yml/badge.svg)](https://github.com/tbug/elixir_interval/actions/workflows/ci.yml)
[![Hex.pm](https://img.shields.io/hexpm/v/interval.svg)](https://hex.pm/packages/interval)
[![Documentation](https://img.shields.io/badge/documentation-gray)](https://hexdocs.pm/interval/)

Datatype and operations for both discrete and continuous intervals,
Inspired by [PostgreSQL's range types](https://www.postgresql.org/docs/current/rangetypes.html).

Find the documentation at https://hexdocs.pm/interval/


## Installation

The package can be installed by adding `interval` to your list of dependencies in `mix.exs`:

```elixir
def deps do
  [
    {:interval, "~> 0.1.3"}
  ]
end
```


## Examples

### Integer intervals

```elixir
a = Interval.new(left: 1, right: 4, bounds: "[]")
b = Interval.new(left: 2, right: 5, bounds: "[]")

assert Interval.contains?(a, b)
assert Interval.overlaps?(a, b)

c = Interval.intersection(a, b) # [2, 4]
d = Interval.union(a, b) # [1, 5]
```

### DateTime intervals

```elixir
# default bound is  "[)"
y2022 = Interval.new(left: ~U[2022-01-01 00:00:00Z], right: ~U[2023-01-01 00:00:00Z])
x = Interval.new(left: ~U[2018-07-01 00:00:00Z], right: ~U[2022-03-01 00:00:00Z])

Interval.intersection(y2022, x)

# %Interval{
#   left: {:inclusive, ~U[2022-01-01 00:00:00Z]},
#   right: {:exclusive, ~U[2022-03-01 00:00:00Z]}
# }
```


## Changelog

### v0.1.3

- Fixed a bug in `Interval.intersection/2` and `Interval.union/2` that causes incorrect bounds
  in some cases.
- The internal `Endpoint` struct has been replaced by a simple 2-tuple.
- Empty intervals are now represented by two identical exclusive points. 
- Added `Interval.size/2`.
- Added parameterized typespec `t:Interval.t/1`

### v0.1.2

- Fixed a correctness bug in intersection, where intersections between
  intervals containing unbounded endpoints would be incorrectly computed.