flawless_state

FlawlessState is a shard that you can include in your objects to provide a simple state machine. It's written as a Struct in order to keep it as fast as possible.

Installation

Add this to your application's shard.yml:

dependencies:
  flawless_state:
    github: jasonl99/flawless_state

Usage

require "flawless_state"

Create an instance property as follows:

property state = FlawlessState::State.new

The default out-of-the-box configuration provides five states. The format is simply: each state as a key has a value of states that can be transitioned into

{
	:new =>         [:initialized, :ready, :complete],
	:initialized => [:ready, :complete],
	:ready =>       [:complete],
	:complete =>    [] of Symbol, 
	:error =>       [] of Symbol
}

If you'd like to use your own states on your object's property, it can be overriden using property state = FlawlessState::State.new(my_states)

To transition between states, provide the new state:

class MyObject
	def complete
  	state.transition_to :completed
  end
end

If a state cannot transition to the new state, a FlawlessState::Exception is raised. You can force a state transition by uisng the force method:

class MyObject
  def error
    state.transition_to! :error
  end
end

You can test if a state is terminal:

my_instantce.state.terminal?

Or get its current value

my_instance.state.current_state

Check to see if it's possible to transition

my_instance.state.transition? :completed

Development

The goal of FlawlessState is to remain as simple as possible, providing a simple but effective state machine. This is very early release, and I'm new to crystal, so I'm sure there'js lots to improve.

Contributing

  1. Fork it ( https://github.com/[your-github-name]/flawless_state/fork )
  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 a new Pull Request

Contributors