block_usage.rb

# method definition
def run_variations(variation_options = {}, &block)
  keys = variation_options.keys
  values = variation_options.fetch_values(*keys)
  variant_klass = Struct.new(*keys)
        
  values.first
        .product(*values[1..-1])
        .each do |variation|
    block.call(variant_klass.new(*variation))
  end
end

# calling the method
run_variations(set: ['蛋炒飯', '紅蘿蔔蛋炒飯'],
               side: ['皮蛋豆腐', '涼拌乾絲', '滷味拼盤'],
               with_sauce: [true, false]) do |combination|
  puts "[Menu option] set: #{combination.set}, side: #{combination.side}, with_sauce: #{combination.with_sauce}"
end

OUTPUT

[Menu option] set: 蛋炒飯, side: 皮蛋豆腐, with_sauce: true
[Menu option] set: 蛋炒飯, side: 皮蛋豆腐, with_sauce: false
[Menu option] set: 蛋炒飯, side: 涼拌乾絲, with_sauce: true
[Menu option] set: 蛋炒飯, side: 涼拌乾絲, with_sauce: false
[Menu option] set: 蛋炒飯, side: 滷味拼盤, with_sauce: true
[Menu option] set: 蛋炒飯, side: 滷味拼盤, with_sauce: false
[Menu option] set: 紅蘿蔔蛋炒飯, side: 皮蛋豆腐, with_sauce: true
[Menu option] set: 紅蘿蔔蛋炒飯, side: 皮蛋豆腐, with_sauce: false
[Menu option] set: 紅蘿蔔蛋炒飯, side: 涼拌乾絲, with_sauce: true
[Menu option] set: 紅蘿蔔蛋炒飯, side: 涼拌乾絲, with_sauce: false
[Menu option] set: 紅蘿蔔蛋炒飯, side: 滷味拼盤, with_sauce: true
[Menu option] set: 紅蘿蔔蛋炒飯, side: 滷味拼盤, with_sauce: false