Initial commit

.gitignore

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+/doc/
+/libs/
+/.crystal/
+/.shards/
+
+
+# Libraries don't need dependency lock
+# Dependencies will be locked in application that uses them
+/shard.lock
+

.travis.yml

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+language: crystal

LICENSE

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+The MIT License (MIT)
+
+Copyright (c) 2016 Vitalii Elenhaupt
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in
+all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+THE SOFTWARE.

README.md

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+# aasm.cr
+
+Easy to use state machine for Crystal.
+
+## Installation
+
+
+Add this to your application's `shard.yml`:
+
+```yaml
+dependencies:
+  aasm:
+    github: veelenga/aasm.cr
+```
+
+## Usage
+
+```crystal
+require "aasm"
+
+class Transaction
+  include AASM
+
+  def act_as_state_machine
+    aasm.state :pending, initial: true
+    aasm.state :active,  enter: -> { puts "Just got activated" }
+    aasm.state :completed
+
+    aasm.event :activate do |t|
+      t.transitions from: :pending, to: :active
+    end
+
+    aasm.event :complete do |t|
+      t.transitions from: :pending, to: :active
+    end
+  end
+end
+
+t = Transaction.new.tap &.act_as_state_machine
+t.state          #=> :pending
+t.next_state     #=> :active
+t.fire :activate # Just got activated
+t.state          #=> :active
+t.next_state     #=> :completed
+```
+
+## Contributing
+
+1. Fork it ( https://github.com/veelenga/aasm/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

shard.yml

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+name: aasm
+version: 0.1.0
+
+authors:
+  - Vitalii Elenhaupt <velenhaupt@gmail.com>
+
+license: MIT

spec/aasm_spec.cr

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+require "./spec_helper"
+
+describe Aasm do
+  # TODO: Write tests
+
+  it "works" do
+    false.should eq(true)
+  end
+end

spec/spec_helper.cr

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+require "spec"
+require "../src/aasm"

src/aasm.cr

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+require "./aasm/*"
+
+module AASM
+  abstract def act_as_state_machine
+
+  def aasm
+    @aasm ||= AASM::StateMachine.new
+  end
+
+  def state
+    aasm.current_state_name
+  end
+
+  def next_state
+    aasm.next_state
+  end
+
+  def fire(event : Symbol)
+    aasm.fire event
+  end
+end

src/aasm/event.cr

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+class AASM::Event
+
+  getter! :transition
+
+  def transitions(from = nil : Symbol, to = nil : Symbol)
+    @transition = Transition.new({from: from, to: to})
+  end
+end

src/aasm/exceptions.cr

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+module AASM
+  class NoSuchEventException < Exception
+    def initialize(event_name)
+      super "Event '#{event_name}' does not exist."
+    end
+  end
+
+  class EventAlreadyDefinedException < Exception
+    def initialize(event_name)
+      super "Event '#{event_name}' already defined."
+    end
+  end
+
+  class NoSuchStateException < Exception
+    def initialize(state_name)
+      super "State '#{state_name}' does not exist."
+    end
+  end
+
+  class StateAlreadyDefinedException < Exception
+    def initialize(state_name)
+      super "State '#{state_name}' already defined."
+    end
+  end
+end

src/aasm/state.cr

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+struct AASM::State
+
+  getter :enter, :guard
+
+  def initialize(opts)
+    @enter = opts[:enter]?
+    @guard = opts[:guard]?
+  end
+end

src/aasm/state_machine.cr

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+class AASM::StateMachine
+
+  getter current_state_name
+
+  def initialize
+    @states = {} of Symbol => State
+    @events = {} of Symbol => Event
+    @transition_table = [] of Transition
+  end
+
+  def state(name : Symbol, initial = false : Bool, enter = nil : (->), guard = nil : (-> Bool))
+    check_state_already_defined name
+    state = State.new({enter: enter, guard: guard})
+    @current_state_name = name if initial || @current_state_name.nil?
+    @states[name] = state
+  end
+
+  def event(name : Symbol)
+    check_event_already_defined name
+    event = Event.new
+    yield event
+    transition = event.transition
+    check_states_exists transition.from, transition.to
+    @transition_table << transition
+    @events[name] = event
+  end
+
+  def next_state
+    @transition_table.each do |t|
+      return t.to if t.from == @current_state_name
+    end
+    nil
+  end
+
+  def fire(event_name : Symbol)
+    check_event_exists event_name
+
+    transition = @events[event_name].transition
+    if transition.from == @current_state_name
+      state = @states[transition.to]
+      if state.guard.nil? || state.guard.not_nil!.call
+        state.enter.try &.call
+        @current_state_name = transition.to
+      end
+    end
+  end
+
+  private def check_states_exists(*state_names)
+    state_names.each do |state_name|
+      raise NoSuchStateException.new state_name unless @states[state_name]?
+    end
+  end
+
+  private def check_state_already_defined(*state_names)
+    state_names.each do |state_name|
+      raise StateAlreadyDefinedException.new state_name if @states[state_name]?
+    end
+  end
+
+  private def check_event_exists(*event_names)
+    event_names.each do |event_name|
+      raise NoSuchEventException.new event_name unless @events[event_name]?
+    end
+  end
+
+  private def check_event_already_defined(*event_names)
+    event_names.each do |event_name|
+      raise EventAlreadyDefinedException.new event_name if @events[event_name]?
+    end
+  end
+end

src/aasm/transition.cr

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+struct AASM::Transition
+
+  getter! :from, :to
+
+  def initialize(opts)
+    @from = opts[:from]
+    @to = opts[:to]
+  end
+end

src/aasm/version.cr

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+module AASM
+  VERSION = "0.1.0"
+end