https://github.com/svenfuchs/simple_states

A super-slim statemachine-like support library
https://github.com/svenfuchs/simple_states

Last synced: 6 days ago
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A super-slim statemachine-like support library

• Host: GitHub
• URL: https://github.com/svenfuchs/simple_states
• Owner: svenfuchs
• License: mit
• Created: 2011-07-31T20:17:20.000Z (over 13 years ago)
• Default Branch: master
• Last Pushed: 2017-07-25T12:09:49.000Z (over 7 years ago)
• Last Synced: 2024-10-26T22:39:40.314Z (20 days ago)
• Language: Ruby
• Homepage:
• Size: 101 KB
• Stars: 95
• Watchers: 6
• Forks: 16
• Open Issues: 4
• Metadata Files:
  • Readme: README.md
  • License: LICENSE

Awesome Lists containing this project

• awesome-ruby-toolbox - simple_states - [description] (Rails Plugins / State Machines)
• awesome-ruby - simple_states - A super-slim statemachine-like support library. (State Machines)

README

        
# simple\_states [![Build Status](https://secure.travis-ci.org/svenfuchs/simple_states.png)](http://travis-ci.org/svenfuchs/simple_states)

A super-slim (~200 loc) statemachine-like support library focussed on use in

Travis CI.

Note that the current version behaves slightly differently, and comes with

reduced features compared to the original version. If you are looking for the

original version see the tag `v1.1.0.rc11`.

## Usage

Define states and events like this:

``` ruby

class Foo

  include SimpleStates

  event :start,  if: :start?

  event :finish, to: [:passed, :failed], after: :notify, unless: :finished?

  attr_accessor :state, :started_at, :finished_at

  def start

    # start foo

  end

  def start?

    true

  end

  def notify(event)

    # notify about event on foo

  end

end

```

SimpleStates expects your model to support attribute accessors for `:state`.

Event options have the following well-known meanings:

``` ruby

:to     # allowed target states to transition to, deferred from the event name if not given

:if     # only proceed if the given method returns true

:unless # only proceed if the given method returns false

:before # run the given method before running `super` and setting the new state

:after  # run the given method at the very end

```

All of these options except can be given as a single symbol or string or as an

Array of symbols or strings.

Calling `event` will effectively add methods to a proxy module which is

prepended to your class (included to the singleton class of your class'

instances on 1.9). E.g. declaring `event :start` in the example above will add

methods `start` and `start!` to a module included to the singleton class of

instances of `Foo`.

This method will

1. check if `:if`/`:unless` conditions apply (if given) and just return from the method otherwise

2. run `:before` callbacks (if given)

3. set the object's `state` to the target state

4. set the object's `[state]_at` attribute to `Time.now` if the object defines a writer for it

5. call `super` if Foo defines the current method (i.e. call `start` but not `finish` in the example above)

6. run `:after` callbacks (if given)

You can define options for all events like so:

``` ruby

event :finish, after: :cleanup

event :all,    after: :notify

```

This will call :cleanup first and then :notify on :finish.

If no target state was given for an event then SimpleStates will try to derive

it from the event name. I.e. for an event `start` it will check the states

list for a state `started` and use it. If it can not find a target state this

way then it will raise an exception.