Date and DateTime extensions for the Hanke-Henry Calendar
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Hanke-Henry Calendar

hanke-henry is a gem that deals with the proposed Hanke-Henry Calendar. This calendar has the following characteristics over the presently adopted Gregorian Calendar:

  1. Calendar remains identical for the most part.
  2. No time zones.
  3. No Daylight Savings Time.

The typical year in the current Gregorian calendar has 365 days, which is 52 weeks and 1 day. The leap years occur every 4 years (with some exceptions). The basic idea of the Hanke-Henry calendar is to gather the overflow days of the typical year and the leap days and into chunks of 7, which will form a mini-month (called Xtr) at the end of the year every so often.

The H-H calendar also proposes to abolish time zones and Daylight Savings Time, essentially standardizing on the current UTC.

hanke-henry extends the Date and DateTime classes to deal with this calendar.


Add this line to your application's Gemfile:

gem 'hanke-henry'

And then execute:

$ bundle

Or install it yourself as:

$ gem install hanke-henry


require 'hanke-henry' # requires 'date' as well
d1 = Date.hh(2012, 1, 1) # => #<Date: 2012-01-01 ((2455928j,0s,0n),+0s,2299161j)>
d1.hh # => "2012-1-1"
d1.xtr? # => false
d2 = Date.hh(2015, :x, 5) # => #<Date: 2015-12-31 ((2457388j,43200s,0n),+0s,2299161j)>
d2.xtr? # => true


By contributing, you certify that you have full legal rights to your contribution and agree that it can be redistributed under the license described in LICENSE.txt.

  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


git clone git://
cd hanke-henry
bundle install
bundle exec autotest