Draco::State

This library provides a DSL to define state based entities in Draco.

This plugin allows you to specify a set of components where only one component can be active at a time. This allows you to build state machine based systems or just to keep your entities from getting in unnatural states.

class Guard < Draco::Entity
  include Draco::State

  state [Walking, Running, Jumping, Standing], default: Standing.new
end

If you don't define a default component, it will create an instance of the first component in the list. When you want to switch states, just add the new component:

guard = Guard.new
guard.components << Walking.new

guard.state_changed.from
# => {class: "Standing"}

guard.state_changed.to
# => {class: "Walking"}

guard.state_changed.at
# => 2021-01-05 00:44:24.522127229 +0700

Since the Draco::StateChanged component was added, we can write a system to deal with newly changed entities:

class StateSystem < Draco::System
  filter Draco::StateChanged

  def tick(args)
    entity.components.add(Active)
    entity.components.delete(entity.state_changed)
  end
end

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.

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/[USERNAME]/draco-state. This project is intended to be a safe, welcoming space for collaboration, and contributors are expected to adhere to the code of conduct.

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

Everyone interacting in the Draco::StateMachine project's codebases, issue trackers, chat rooms and mailing lists is expected to follow the code of conduct.