Periodical

Periodical is a simple framework for working with durations and periods. A duration measures a range of time bounded by a from date and to date. A period is a relative unit of time such as 4 weeks.

The original idea for this library came from a Python script which performed backup rotation from 2009. In particular, I thought it had a novel way to retain backups according to a given policy (e.g. one backup every year for 10 years, one backup every month for 12 months, one backup every week for 8 weeks, one backup every day for 30 days). This is done by constructing a special slot based hash structure with keys based on the date being stored. This functionality is used by LSync for performing backup rotation (i.e. deleting old backups).

In addition, I had a need to implement periodical billing in Financier. Not only can this gem advance a date by a given period, it can compute the number of periods between two dates. This is useful for invoicing, say, once every 6 months for a weekly or monthly service.

Add this line to your application's Gemfile:

$ bundle add periodical

The main use case for this framework involves periodic billing or accounting (e.g. calculating fortnightly rental payments).

duration = Periodical::Duration.new(Date.parse("2010-01-01"), Date.parse("2010-02-01"))
period = Periodical::Period.new(2, :weeks)

# How many periods in the duration?
count = duration / period

# Calculate the date which is 2 * (2 weeks)
next = period.advance(duration.from, 2)

1. Fork it
2. Create your feature branch (git checkout -b my-new-feature)
3. Commit your changes (git commit -am 'Add some feature')
4. Push to the branch (git push origin my-new-feature)
5. Create new Pull Request

Released under the MIT license.

Copyright, 2010, 2014, 2016, by Samuel G. D. Williams.

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

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