Module: Philiprehberger::StateMachine::Validation

Defined in:
lib/philiprehberger/state_machine/validation.rb

Overview

Validates state machine definitions for unreachable states and other issues.

Class Method Summary collapse

Class Method Details

.predecessors(definition, state) ⇒ Array<Symbol>

Find all states that can transition to the given state.

Parameters:

Returns:

  • (Array<Symbol>) 


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# File 'lib/philiprehberger/state_machine/validation.rb', line 43

def self.predecessors(definition, state)
  result = []
  definition.events.each_value do |transitions|
    transitions.each do |t|
      next unless t.to == state

      Array(t.from).each do |from_state|
        result << from_state unless result.include?(from_state)
      end
    end
  end
  result
end

.reachable_states(definition) ⇒ Array<Symbol>

Find all states reachable from the initial state via BFS.

Parameters:

  • definition (Definition) —

    the state machine definition

Returns:

  • (Array<Symbol>) —

    reachable states



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# File 'lib/philiprehberger/state_machine/validation.rb', line 20

def self.reachable_states(definition)
  visited = Set.new([definition.initial])
  queue = [definition.initial]

  until queue.empty?
    current = queue.shift
    targets = targets_from(definition, current)
    targets.each do |target|
      unless visited.include?(target)
        visited << target
        queue << target
      end
    end
  end

  visited.to_a
end

.unreachable_states(definition) ⇒ Array<Symbol>

Find states that can never be reached from the initial state.

Parameters:

  • definition (Definition) —

    the state machine definition

Returns:

  • (Array<Symbol>) —

    unreachable states



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# File 'lib/philiprehberger/state_machine/validation.rb', line 11

def self.unreachable_states(definition)
  reachable = reachable_states(definition)
  definition.all_states - reachable
end