Xavier

Xavier tracks and reverts state mutations (changes in instance, class, and class instance variables).

Installation

Add this line to your application's Gemfile:

gem 'xavier'

And then execute:

$ bundle

Or install it yourself as:

$ gem install xavier

Usage

Observing a class:

class EvilSingleton
  @@mutated = false
  @mutated = false

  def self.mutate
    @@mutated = true
    @mutated = true
  end

  def self.mutated?
    @@mutated && @mutated
  end
end

Xavier.observe(EvilSingleton) do
  EvilSingleton.mutated? # => false
  EvilSingleton.mutate
  EvilSingleton.mutated? # => true
end

EvilSingleton.mutated? # => false

Observing an instance:

class InstanceSingleton
  def initialize
    @mutated = false
  end

  def mutate
    @mutated = true
  end

  def mutated?
    @mutated
  end
end

evil_singleton = InstanceSingleton.new

Xavier.observe(evil_singleton) do
  evil_singleton.mutated? # => false
  evil_singleton.mutate
  evil_singleton.mutated? # => true
end

evil_singleton.mutated? # => false

Development

After checking out the repo, run bin/setup to install dependencies. Then, run rake spec to run the tests. You can also run:

• bin/console for an interactive prompt that will allow you to experiment.
• rake rubocop to lint the code.
• rake verify_measurements to generate a report of the Yard documentation.
• rake yard:junk to lint the Yard documentation.

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 rubygems.org.

Contributing

Bug reports and pull requests are welcome on GitHub at https://github.com/[USERNAME]/xavier.