Month - library focused on working with months, rather than Date/DateTime

At Heresy we have a lot of date logic around months and quarters and forecasting horizons. We started using Elixir’s Date module, naturally, but ended with a lot of functions that deal with the necessary day field of the Date struct.

We wanted to simplify our code a bit and ended up extracting some of that code into month, which now could be found in the usual places:

• https://hex.pm/packages/month
• https://hexdocs.pm/month/Month.html
• https://github.com/heresydev/month

Here’s a sample:

iex> import Month.Sigils
Month.Sigils

iex> Month.utc_now!()
~M[2019-03]

iex> range = Month.Range.new!(~M[2019-01], ~M[2019-03])
#Month.Range<~M[2019-01], ~M[2019-03]>

iex> range.months
[~M[2019-01], ~M[2019-02], ~M[2019-03]]

iex> Month.Period.shift(range, 3)
#Month.Range<~M[2019-04], ~M[2019-06]>

Everything is built on top of Date so no extra dependencies.

It’s a very specific use case perhaps, but hopefully someone would find it useful!