Method: Kleene::DSL#append!

Defined in:
lib/kleene/dsl.rb

#append!(a, b) ⇒ Object

Destructively append b onto a Appending produces a machine that matches all the strings in machine a followed by all the strings in machine b. This differs from ‘seq` in that the composite machine’s final states are the union of machine a’s final states and machine b’s final states.



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# File 'lib/kleene/dsl.rb', line 127

def append!(a, b)
  a.alphabet = a.alphabet | b.alphabet

  # add an epsilon transition from each final state of machine a to the start state of maachine b.
  a.final_states.each do |final_state|
    a.add_transition(NFATransition::Epsilon, final_state, b.start_state)
  end

  # add all of machine b's transitions to machine a
  b.all_transitions.each {|transition| a.add_transition(transition.token, transition.from, transition.to) }
  # a.final_states = a.final_states | b.final_states
  a.update_final_states

  a
end