ActiveRecall is a spaced-repetition system that allows you to treat arbitrary ActiveRecord models as if they were flashcards to be learned and reviewed. It it based on, and is intended to be backwards compatible with, the okubo gem. The primary differentiating features are that it lets the user specify the scheduling algorithm and is fully compatible with (and requires) Rails 6+ and Ruby 3+.

Add this line to your application's Gemfile:

gem 'active_recall'

And then execute:

$ bundle
$ rails generate active_recall
$ rails db:migrate

Or, if you were using the Okubo gem and want to migrate your data over, execute:

$ bundle
$ rails generate active_recall --migrate_data true
$ rails db:migrate

Or install it yourself as:

$ gem install active_recall

You can configure the desired SRS algorithm during runtime:

ActiveRecall.configure do |config|
  config.algorithm_class = ActiveRecall::FibonacciSequence
end

Algorithms include FibonacciSequence, LeitnerSystem, SoftLeitnerSystem, and SM2 (see here). For Rails applications, try doing this from within an initializer file.

Assume you have an application allowing your users to study words in a foreign language. Using the has_deck method you can set up a deck of flashcards that the user will study:

class Word < ActiveRecord::Base
end

class User < ActiveRecord::Base
  has_deck :words
end

user = User.create!(:name => "Robert")
word = Word.create!(:kanji => "日本語", :kana => "にほんご", :translation => "Japanese language")

You can add words and record attempts to guess the word as right or wrong. Various methods exist to allow you to access subsets of this collection:

# Initially adding a word
user.words << word
user.words.untested #=> [word]

# Guessing a word correctly (when using a binary algorithm)
user.right_answer_for!(word)
user.words.known #=> [word]

# Guessing a word incorrectly
user.wrong_answer_for!(word)
user.words.failed #=> [word]

# Listing all words
user.words #=> [word]

As time passes, words need to be reviewed to keep them fresh in memory:

# Three days later...
user.words.known #=> []
user.words.expired #=> [word]

Guessing a word correctly several times in a row results in the word taking longer to expire, and demonstrates mastery of that word.

user.right_answer_for!(word)
# One week later...
user.words.expired #=> [word]
user.right_answer_for!(word)
# Two weeks later...
user.words.expired #=> [word]
user.right_answer_for!(word)
# One month later...
user.words.expired #=> [word]

When using a gradable algorithm (rather than binary) such as the SM2 algorithm, you will need to supply your own grade along with the item:

grade = 3
user.score!(grade, word)

# Using the binary-only methods will raise an error
user.right_answer_for!(word)
=> ActiveRecall::IncompatibleAlgorithmError

In addition to an expired method, ActiveRecall provides a suggested reviewing sequence for all unknown words in the deck. Words are randomly chosen from all untested words, failed, and finally expired in order of precedence.

user.words.review #=> [word]
user.right_answer_for!(word)
# ... continuing until all untested, failed, and expired words have been guessed correctly.
user.words.review #=> []

You can also just get the next word to review:

user.words.next #=> word
user.right_answer_for!(word)
# ... continuing until all untested, failed, and expired words have been guessed correctly.
user.words.next #=> nil

After checking out the repo, run bin/setup to install dependencies. Then, run bin/spec 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 rubygems.org.

Bug reports and pull requests are welcome on GitHub at https://github.com/jaysonvirissimo/active_recall.

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