Ruby 如何返回到调用方法？

我有一个使用方法进行验证的程序，如果验证失败，我希望返回到调用它的方法，例如：

def obtain_pokemon_name
  print 'Enter Pokemon: '
  pokemon = gets.chomp.capitalize
  obtain_basic_attack(pokemon)
end

def obtain_basic_attack(poke)
  print 'Enter basic attack: '
  basic_attack = gets.chomp.downcase
  check_attacks(poke, basic_attack)
  obtain_spec_attack(poke)
end

def obtain_spec_attack(poke)
  print 'Enter special attack: '
  spec_attack = gets.chomp.downcase
  check_attacks(poke, spec_attack)
end

def check_attacks(pokemon, attack)
  if POKEMON_ATTACKS[pokemon][attack] == nil
    puts "#{attack} is not one of #{pokemon}'s attacks, try again.."
    return # to where this function was called
  else
    attack
  end
end

begin
  obtain_pokemon_name
rescue => e
  puts "Failed with error code: #{e}"
end

运行此操作时：

Enter Pokemon: arbok
Enter basic attack: eat
eat is not one of Arbok's attacks, try again..
Enter special attack: test
test is not one of Arbok's attacks, try again..

攻击列表：

POKEMON_ATTACKS = {
    'Bulbasaur' => {'tackle' => 10.9, 'vine whip' => 15.4, 'power whip' => 21.4, 'seed bomb' => 12.5, 'sludge bomb' => 19.2},
    'Ivysaur' => {'razor leaf' => 10.3, 'vine whip' => 15.4, 'power whip' => 21.4, 'sludge bomb' => 19.2, 'solar beam' => 13.3},
    'Kakuna' => {'bug bite' => 13.3, 'poison sting' => 10.3, 'struggle' => 8.8},
    'Beedrill' => {'bug bite' => 13.3, 'poison jab' => 14.3, 'aerial ace' => 8.6, 'sludge bomb' => 19.2, 'x-scissor' => 14.3},
    'Pidgey' => {'quick attack' => 7.5, 'tackle' => 10.9, 'aerial ace' => 8.6, 'air cutter' => 7.6, 'twister' => 5.6},
    'Ekans' => {'acid' => 9.5, 'poison sting' => 10.3, 'gunk shot' => 20.0, 'sludge bomb' => 19.2, 'wrap' => 3.8},
    'Arbok' => {'acid' => 9.5, 'bite' => 12.0, 'dark pulse' => 12.9, 'gunk shot' => 20.0, 'sludge wave' => 17.6},
}

因此，我的问题是，如果数据中不存在攻击，如何返回调用方法？例如，如果我调用

arbok

，而他的攻击是

attack

，如果它在散列中不存在，我将如何返回到

获取基本攻击（poke）

方法？

就在这里：

   puts "#{attack} is not one of #{pokemon}'s attacks, try again.."
    return # to where this function was called

您应该再次调用原始方法。i、 e

  if POKEMON_ATTACKS[pokemon][attack] == nil
    puts "#{attack} is not one of #{pokemon}'s attacks, try again.."
    return obtain_spec_attack(poke)

您也可以将此逻辑添加到

获取规范\u攻击中

：

def obtain_spec_attack(poke)
  loop do
    print 'Enter special attack: '
    spec_attack = gets.chomp.downcase
    attack_found = check_attacks(poke, spec_attack)
    if attack_found
      break attack_found # this will return attack_found from the loop
    else
      puts "attack not found"
    end
  end
end

---

编辑

再看看你的问题，我意识到你想回到一个多层的方法上来。您可以使用我已经概述的方法，或者使用rescue：

def obtain_basic_attack(poke)
  begin
    print 'Enter basic attack: '
    basic_attack = gets.chomp.downcase
    check_attacks(poke, basic_attack)
    obtain_spec_attack(poke)
  rescue AttackNotFoundError
    retry # runs the 'begin' block again
  end
end

def obtain_spec_attack(poke)
  print 'Enter special attack: '
  spec_attack = gets.chomp.downcase
  check_attacks(poke, spec_attack)
end

def check_attacks(pokemon, attack)
  if POKEMON_ATTACKS[pokemon][attack] == nil
    puts "#{attack} is not one of #{pokemon}'s attacks, try again.."
    raise AttackNotFoundError
  else
    attack
  end
end

为了使用自定义错误，如

AttackNotFoundError

，您需要在某个地方定义错误类：

class AttackNotFoundError < StandardError; end

类攻击NotFoundError

您可以使用任何错误，例如

raise StandardError

，但最好限制您要挽救的错误，这样您就不会意外地挽救不相关的错误

就在这里：

   puts "#{attack} is not one of #{pokemon}'s attacks, try again.."
    return # to where this function was called

您应该再次调用原始方法。i、 e

  if POKEMON_ATTACKS[pokemon][attack] == nil
    puts "#{attack} is not one of #{pokemon}'s attacks, try again.."
    return obtain_spec_attack(poke)

您也可以将此逻辑添加到

获取规范\u攻击中

：

def obtain_spec_attack(poke)
  loop do
    print 'Enter special attack: '
    spec_attack = gets.chomp.downcase
    attack_found = check_attacks(poke, spec_attack)
    if attack_found
      break attack_found # this will return attack_found from the loop
    else
      puts "attack not found"
    end
  end
end

---

编辑

再看看你的问题，我意识到你想回到一个多层的方法上来。您可以使用我已经概述的方法，或者使用rescue：

def obtain_basic_attack(poke)
  begin
    print 'Enter basic attack: '
    basic_attack = gets.chomp.downcase
    check_attacks(poke, basic_attack)
    obtain_spec_attack(poke)
  rescue AttackNotFoundError
    retry # runs the 'begin' block again
  end
end

def obtain_spec_attack(poke)
  print 'Enter special attack: '
  spec_attack = gets.chomp.downcase
  check_attacks(poke, spec_attack)
end

def check_attacks(pokemon, attack)
  if POKEMON_ATTACKS[pokemon][attack] == nil
    puts "#{attack} is not one of #{pokemon}'s attacks, try again.."
    raise AttackNotFoundError
  else
    attack
  end
end

为了使用自定义错误，如

AttackNotFoundError

，您需要在某个地方定义错误类：

class AttackNotFoundError < StandardError; end

类攻击NotFoundError

---

您可以使用任何错误，例如

raise StandardError

，但最好限制您要挽救的错误，这样您就不会意外地挽救不相关的错误

我建议你看看递归。这里有一个很好的类比：我建议您看看递归。这里有一个很好的类比：如果你看代码，有不止一个调用方法。不过，该循环可能会起作用，您也可以使用rescue。我会加上一个例子。这是一个天才的想法！！！我甚至都没想过救援条款，非常感谢！当然，顺便说一句，如果口袋妖怪攻击[POKEMON][attack]==nil通常是不必要的，你可以删除

==nil

，

如果
将评估它是否真实/falsy，我无法确定这是否是滥用异常。习惯上，您可能更愿意使用
throw
/
catch
。如果您查看代码，就会发现不止一个调用方法。不过，该循环可能会起作用，您也可以使用rescue。我会加上一个例子。这是一个天才的想法！！！我甚至都没想过救援条款，非常感谢！当然，顺便说一句，如果口袋妖怪攻击[POKEMON][attack]==nil
通常是不必要的，你可以删除
==nil
，
如果
将评估它是否真实/falsy，我无法确定这是否是滥用异常。习惯上，您可能更愿意使用
throw
/
catch
。