PrivateStruct is a Struct that does not violate encapsulation by default.


Add this line to your application's Gemfile:

gem 'private_struct'

And then execute:

$ bundle

Or install it yourself as:

$ gem install private_struct


require 'private_struct'

Customer =, :address) do
  def greeting
    "Hello #{name}!"
dave ="Dave", "123 Main")
dave.greeting  # => "Hello Dave!"
dave.address  # => NoMethodError: private method `address' called for #<Customer:0x007fa723855058>


After checking out the repo, run bin/setup to install dependencies. Then, run rake test to run the tests. You can also run bin/console for an interactive prompt that will allow you to experiment.

To install this gem onto your local machine, run bundle exec rake install. To release a new version, update the version number in version.rb, and then run bundle exec rake release, which will create a git tag for the version, push git commits and tags, and push the .gem file to


Bug reports and pull requests are welcome on GitHub at This project is intended to be a safe, welcoming space for collaboration, and contributors are expected to adhere to the Contributor Covenant code of conduct.


The gem is available as open source under the terms of the MIT License.