Class: MicroFSM

Inherits:
Object
  • Object
show all
Defined in:
lib/version.rb,
lib/microfsm.rb

Constant Summary collapse

VERSION =

2021-01-24

'0.0.1'
InvalidEvent = 
Class.new(NoMethodError)
InvalidState = 
Class.new(ArgumentError)
InvalidTransition = 
Class.new(ArgumentError)

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(initial_state) ⇒ MicroFSM

Returns a new instance of MicroFSM.



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# File 'lib/microfsm.rb', line 10

def initialize(initial_state)
  @state = initial_state
  @transitions_for = {}
  @callbacks_for = {}
end

Instance Attribute Details

#state ⇒ Object (readonly)

Returns the value of attribute state.



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# File 'lib/microfsm.rb', line 8

def state
  @state
end

Instance Method Details

#events ⇒ Object 



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# File 'lib/microfsm.rb', line 46

def events
  @transitions_for.keys.sort
end

#states ⇒ Object 



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# File 'lib/microfsm.rb', line 54

def states
  @transitions_for.values.map(&:to_a).flatten.uniq.sort
end

#trigger(event) ⇒ Object 



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# File 'lib/microfsm.rb', line 31

def trigger(event)
  trigger?(event) and transit(event)
end

#trigger!(event) ⇒ Object 



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# File 'lib/microfsm.rb', line 35

def trigger!(event)
  trigger(event) or
    raise InvalidState.new("Event '#{event}' not valid from state '#{@state}'")
end

#trigger?(event) ⇒ Boolean

Returns:

  • (Boolean)

Raises:



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# File 'lib/microfsm.rb', line 40

def trigger?(event)
  raise InvalidEvent unless @transitions_for.has_key?(event)

  @transitions_for[event].has_key?(state)
end

#triggerable_events ⇒ Object 



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# File 'lib/microfsm.rb', line 50

def triggerable_events
  events.select { |event| trigger?(event) }.sort
end

#when(event, transitions, &block) ⇒ Object 



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# File 'lib/microfsm.rb', line 16

def when(event, transitions, &block)
  @transitions_for[event] ||= {}
  @callbacks_for[event] ||= {}

  transitions.each do |from, to|
    nto = @transitions_for[event][from]
    raise InvalidTransition if nto && nto != to

    @transitions_for[event][from] = to
    @callbacks_for[event][from] ||= []
    @callbacks_for[event][from] << block if block_given?
  end
  self
end