gistfile1.rb

MACHINE_RULEBOOK = DTMRulebook.new([
  TMRule.new(:delete_next_bit,    '0', :increment_counter,  'X', :left),  # cross out 0 from input
  TMRule.new(:delete_next_bit,    '1', :increment_counter,  'X', :left),  # cross out 1 from input
  TMRule.new(:delete_next_bit,    '_', :clean_up,           '_', :left),  # clean up the tape
  TMRule.new(:delete_next_bit,    'X', :delete_next_bit,    'X', :right), # scan right
  TMRule.new(:delete_next_bit,    'Z', :delete_next_bit,    'Z', :right), # scan right

  TMRule.new(:increment_counter,  '1', :increment_counter,  'Z', :left),  # increment counter, carry the 1
  TMRule.new(:increment_counter,  'Z', :delete_next_bit,    '1', :right), # increment counter
  TMRule.new(:increment_counter,  '_', :delete_next_bit,    '1', :right), # increment counter (overflowed)
  TMRule.new(:increment_counter,  'X', :increment_counter,  'X', :left),  # scan left

  TMRule.new(:clean_up,           'X', :clean_up,           '_', :left),  # erase crossed-out input
  TMRule.new(:clean_up,           'Z', :clean_up,           '0', :left),  # convert Z to 0 (binary)
  TMRule.new(:clean_up,           '1', :clean_up,           '1', :left),  # scan left
])