Ruby动态类。如何修复“warning：从变量访问到类别” [英] Ruby Dynamic Classes. How to fix "warning: class variable access from toplevel"

问题描述

我正在尝试编写一个程序，根据从文件读取的配置动态定义ruby类。我知道我可以使用Class.new来做到这一点。这是一个示例程序：

  x = [1,2,3] 
 
 Test = Class。 new do 
 @@ mylist = x 
 
 def foo 
 puts @@ mylist 
 end 
 end 
 
 Test.new .foo 
  

当我运行这个我得到以下输出（使用ruby 1.9.3p0运行）：

 c：/utils/test.rb：4：warning：从toplevel获取类变量访问
c：/utils/test.rb：7：warning ：从toplevel的类变量访问
 1 
 2 
 3 

有谁知道是什么原因导致这些警告，摆脱他们？

我已经尝试替换行tjhat

  @@ mylist = x  

与此

  class_variable_set（：@@ mylist，x） 

但是当我这样做这个错误代替：

 c：/utils/test.rb：7：warning：从toplevel 
c：/ utils / test的类变量访问。 rb：7：在`foo'中：未初始化的类Object（NameError）中的变量@@ mylist来自c：/utils/test.rb的
：11：在`'

提前感谢！

解决方案

只需删除此警告，您应该使用 class_variable_set

  x = [1,2,3] 
 
测试= Class.new do 
 class_variable_set（：@@ mylist，x）
 
 def foo 
 puts @@ mylist 
 end 
 end 
  / pre> 
I'm trying to write a program that dynamically defines ruby classes based on configuration read from a file. I know I can use Class.new to do this. Here's an example program:
x = [1,2,3]

Test = Class.new do
  @@mylist = x

  def foo
    puts @@mylist
  end
end

Test.new.foo
When I run this I get the following output (running with ruby 1.9.3p0):
c:/utils/test.rb:4: warning: class variable access from toplevel
c:/utils/test.rb:7: warning: class variable access from toplevel
1
2
3
Does anyone know what causes these warnings and how I can get rid of them?

I've tried replacing the line tjhat does
@@mylist = x
with this
class_variable_set(:@@mylist, x)
But when I do that I get this error instead:
c:/utils/test.rb:7: warning: class variable access from toplevel
c:/utils/test.rb:7:in `foo': uninitialized class variable @@mylist in Object (NameError)
        from c:/utils/test.rb:11:in `'
Thanks in advance!
解决方案
Just to remove this warning, you should use class_variable_set method:
x = [1,2,3]

Test = Class.new do
  class_variable_set(:@@mylist, x)

  def foo
    puts @@mylist
  end
end


                        
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