将符号分配给ruby中的变量

Question

战士类有散步,攻击等方法,我们可以通过这些方法.方向是"符号",即:向前,向后,向左,向右.

我试图在实例变量(比如说@direction =:forward)中保存符号(例如:forward)并使用变量.根据某些条件,我将"方向"变量更改为不同的符号(比如@方向=:向后).然而,这似乎没有按预期工作.它被解释或以某种方式被视为零.这是我厌倦写的代码

class Player
  @direction_to_go = :backward # default direction
    def reverse_direction
      if @direction_to_go == :backward
        @direction_to_go = :forward
      else
         @direction_to_go = :backward
      end
    end
    def actual_play(warrior,direction)
      # attack
      # walk
      # rest
      # When I try to use direction here , its nil !?
    end
    def play_turn(warrior)
      if warrior.feel(@direction_to_go).wall?
        reverse_direction
      end
      actual_play(warrior,@direction_to_go)
    end
end

我在这里遗漏了一些符号吗？我理解"符号"是一种不可变的字符串,或者是一种更快的枚举.

我是ruby的新手,已经开始使用这个https://www.bloc.io/ruby-warrior/很好的教程来学习ruby,我得到了这个问题.我试过搜索这个,但无法找到我的问题的任何答案.

Answer 1

当你声明:

class Player
    @direction_to_go = :backward # <-- this is class instance variable

    def reverse_direction
      if @direction_to_go == :backward # <-- this is instance variable
        @direction_to_go = :forward
      else
         @direction_to_go = :backward
      end
    end
end

您可以参考ruby:类实例变量与实例变量的差异.

你应该这样声明:

class Player
    def initialize
        @direction_to_go = :backward
    end

    def reverse_direction
      if @direction_to_go == :backward
        @direction_to_go = :forward
      else
         @direction_to_go = :backward
      end
    end
end

Player.new.reverse_direction