无法打印对象

Question

我在努力打印一个对象。 我来自Python，所以Ruby的OO方面并不那么难，但有些机制很难学。 从来没有关于通过覆盖python中的to_s方法打印对象的问题，但在那里，我不能。我让你看下面的代码。 （我也想保持我的项目的队友这个小小的学生项目的RDoc）

gem "rmagick" 
gem "rdoc" 
require "rmagick" 
require "rdoc/rdoc" 
include Magick 
## 
# This class represents the complete +Game+ 
class Game 
    # Debugging accessor 
    attr_accessor :engine 

    ## 
    # Creates a new instance of the game 
    def initialize() 
     @engine = Engine.new 
    end 

    ## 
    # Starts the engine 
    def start() 
     @engine.genRandomGrid() 
    end 
end 
## 
# This class represents the +Controller+ from +MVC+ 
class Engine 
    # Debugging accessor 
    attr_accessor :grid 

    ## 
    # Initiates the needed instance's variables 
    def initialize(x = 10) 
     @grid = Grid.new(x) 
    end 

    ## 
    # Generates a x * x grid of +Cell+ with false value/state 
    def genNewGrid(x = 10) 
     @grid = Grid.new(x) 
    end 

    ## 
    # Fills the current grid with random value 
    def genRandomGrid() 
     @grid.randomGrid() 
     p @grid 
    end 

    ## 
    # Fills the current grid with picture's values 
    def genPictureGrid(path) 
     @grid.picture(path) 
    end 
end 

## 
# This class represents a +Grid+ 
class Grid 
    # Debugging accessor 
    attr_accessor :maxLen #Longueur/Largeur 
    # Debugging accessor 
    attr_accessor :matrix #2 listes. Voir object Cell 
    # Debugging accessor 
    attr_accessor :xIndices #Les indices au dessus des abscisses 
    # Debugging accessor 
    attr_accessor :yIndices #Les indices à gauche des ordonnées 

    ## 
    # Initializes +@grid+, +@xIndices+ and +@yIndices+ with 2D Array 
    def initialize(x = 10) 
     @maxLen = x 
     @matrix = Array.new(x){Array.new(x){Cell.new(false, false)}} 
     @xIndices = Array.new(x){Array.new} 
     @yIndices = Array.new(x){Array.new} 
    end 

    ## 
    # Turns to false a true cell state and to true a false cell state 
    def changeCellState(x, y) 
     @matrix[x][y].changeState 
    end 

    ## 
    # Returns the @maxLen if needed 
    def getLength() 
     return @maxLen 
    end 

    ## 
    # Generates "randomly" the value of each grid's cell 
    def randomGrid() 
     @matrix.each do |j| 
      j.each do |x| 
       rand_value = Random.srand(Random.new_seed) 
       if (rand_value % 2) == 0 
        x.setValue(true) 
       else 
        x.setValue(false) 
       end 
      end 
     end 
     evalIndices() 
     # NB : Class is array 
     p #{@matrix} 
    end 

    ## 
    # TODO : Generates a grid from a picture 
    def picture() 

    end 

    ## 
    # Fills +@xIndices+ and +@yIndices+ with right values 
    def evalIndices() 
     _row = 0 
     _in = false 
     _nb = 0 
     @matrix.each do |j| 
      _in = false 
      _nb = 0 
      j.each do |x| 
       if x.getValue 
        _in = true 
        _nb += 1 
       elsif _in 
        @xIndices[_row].push(_nb) 
        _in = false 
        _nb = 0 
       end 
      end 
      if _in 
       @xIndices[_row].push(_nb) 
       _in = false 
       _nb = 0 
      end 
      _row += 1 
     end 

     for j in 0..@maxLen-1 
      _in = false 
      _nb = 0 
      for i in 0..@maxLen-1 
       if @matrix[i][j].getValue 
        _in = true 
        _nb += 1 
       elsif _in 
        @yIndices[j].push(_nb) 
        _in = false 
        _nb = 0 
       end 
      end 
      if _in 
       @yIndices[j].push(_nb) 
       _in = false 
       _nb = 0 
      end 
     end 
    end 

    def to_s 
     ret = "" 
     @matrix.each do |j| 
      j.each do |cell| 
       ret += cell.getValue 
      end 
      ret += "\n" 
     end 
     return ret 
    end 
end 


## 
# This class represents a +Cell+ 
class Cell 
    # Debugging accessor 
    attr_accessor :state #Etat graphique (GUI) 
    # Debugging accessor 
    attr_accessor :value #Valeur réelle (MOTEUR) 

    ## 
    # Initializes the +@state+ and +@value+ with parameters 
    def initialize(state, value) 
     @state = state 
     @value = value 
    end 

    ## 
    # Makes the +Cell+ object printable 
    def to_s 
     if @value 
      "[X]" 
     else 
      "[ ]" 
     end 
    end 

    ## 
    # Boolean access method 
    def changeState() 
     if @state == true 
      @state = false 
     else 
      @state = true 
     end 
    end 

    ## 
    # Access method 
    def setValue(value) 
     @value = value 
    end 

    ## 
    # Access method 
    def getState() 
     return @state 
    end 

    ## 
    # Access method 
    def getValue() 
     return @value 
    end 

    ## 
    # Verifies if +@state+ and +@value+ are the same 
    def right? 
     return @state && @value 
    end 
end 


game = Game.new 
game.start() 

在引擎类我想要在genRandGrid方法打印@grid但只打印0 .. 9。

Thx。

Answer 1

当您打印它时，@grid变量的类型是什么？

事实证明，它是由@grid.random返回的类型，它不是Grid对象。您可以打印类为保证，并修复代码：

puts @grid.class 

---

代码您共享的需求相当一些改进。 Ruby是一种非常宽容的语言，现在，代码无法很好地管理类型。另外，我不认为习惯用Ruby来实现你的目标是必要的，但是代码可以被简化很多，这可以简化对几个方面的推理，包括类型。