ボウリングのスコア計算プログラム（旧ルール）

bowling.rb

scores = ARGV[0].strip.split(',').flat_map { |p| p == 'X' ? [10, nil] : p.to_i }
frames = scores.each_slice(6).flat_map { |n| n.size.even? ? n.each_slice(2).to_a : [n] }

total = (0..9).inject(0) do |acc, i|
  current_frame, next_frame, after_next_frame = frames.slice(i, 3)
  bonus = [current_frame.first == 10, current_frame.compact.sum == 10].sum { |i| i ? 1 : 0 } # strikeは2投分,spareは1投分
  acc + current_frame.compact.sum + [next_frame, after_next_frame].flatten.compact.take(bonus).sum
end

puts total