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# http://en.literateprograms.org/Quadruple_Turing_Machine_(Ruby)?action=history&offset=20081007052617
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# Retrieved from: http://en.literateprograms.org/Quadruple_Turing_Machine_(Ruby)?oldid=14850

require_relative 'state'
class TuringMachine
  attr_accessor :start_state
  attr_reader :accepting_states
  attr_reader :transitions

  def initialize
    @accepting_states = []
    @transitions = Hash.new{ [ :invalid, :L ] }
  end

  def simulate(input_string, map)
    state = State.new(@start_state, input_string)
    state.trace(map)
    until @accepting_states.include?(state.control_state)
      action, next_state =
        @transitions[[state.control_state, state.current_symbol]]
      begin
        state.update(action, next_state, map)
      rescue Exception => e
        puts e
        return
      end
      state.trace(map)
    end
  end

end