ruby-1.8.6-p383 > Hopcroft::Regex.parse("a|b")
   => #<Hopcroft::Regex::Alternation:0x122698c @expressions=[#<Hopcroft::Regex::Char:0x12240ec @expression="a">, #<Hopcroft::Regex::Char:0x1224a4c @expression="b">]>
  ruby-1.8.6-p383 > Hopcroft::Regex.parse("a|b").to_machine
   => #<Hopcroft::Machine::StateMachine:0x121f074 @start_state=State 1 {start: true, final: false, transitions: 2}>
  ruby-1.8.6-p383 > Hopcroft::Regex.parse("a|b").to_machine.to_dfa
   => #<Hopcroft::Machine::StateMachine:0x120d630 @start_state=State 12 {start: true, final: false, transitions: 2}>

  ruby-1.8.6-p383 > Hopcroft::Regex.parse("a|b").to_machine
   => #<Hopcroft::Machine::StateMachine:0x5f1b1c @start_state=State 24 {start: true, final: false, transitions: 2}>
  ruby-1.8.6-p383 > Hopcroft::Regex.parse("a|b").to_machine.state_table
   =>
  +-------------+------------+------------+--------------------------------------+
  |             | b          | a          | Hopcroft::Machine::EpsilonTransition |
  +-------------+------------+------------+--------------------------------------+
  | State 32    | * State 33 |            |                                      |
  | State 30    |            | * State 31 |                                      |
  | -> State 29 |            |            | State 30, State 32                   |
  +-------------+------------+------------+--------------------------------------+

  ruby-1.8.6-p383 > Hopcroft::Regex.parse("a|b").to_machine.to_dfa.state_table
   =>
  +-------------+----------+----------+
  |             | a        | b        |
  +-------------+----------+----------+
  | -> State 21 | State 22 | State 23 |
  +-------------+----------+----------+