class ActionDispatch::Journey::GTG::TransitionTable

def move(t, full_string, start_index, end_index)
  return [] if t.empty?
  next_states = []
  tok = full_string.slice(start_index, end_index - start_index)
  token_matches_default_component = DEFAULT_EXP_ANCHORED.match?(tok)
  t.each { |s, previous_start|
    if previous_start.nil?
      # In the simple case of a "default" param regex do this fast-path
      # and add all next states.
      if token_matches_default_component && states = @stdparam_states[s]
        states.each { |re, v| next_states << [v, nil].freeze if !v.nil? }
      end
      # When we have a literal string, we can just pull the next state
      if states = @string_states[s]
        next_states << [states[tok], nil].freeze unless states[tok].nil?
      end
    end
    # For regexes that aren't the "default" style, they may potentially
    # not be terminated by the first "token" [./?], so we need to continue
    # to attempt to match this regexp as well as any successful paths that
    # continue out of it. both paths could be valid.
    if states = @regexp_states[s]
      slice_start = if previous_start.nil?
        start_index
      else
        previous_start
      end
      slice_length = end_index - slice_start
      curr_slice = full_string.slice(slice_start, slice_length)
      states.each { |re, v|
        # if we match, we can try moving past this
        next_states << [v, nil].freeze if !v.nil? && re.match?(curr_slice)
      }
      # and regardless, we must continue accepting tokens and retrying this regexp.
      # we need to remember where we started as well so we can take bigger slices.
      next_states << [s, slice_start].freeze
    end
  }
  next_states
end