如何使模块包含在类中 | 如何使模块包含在类中

本文介绍了如何使模块包含在类中的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！

问题描述

请注意， ancestors

 code>，< => ， included_modules 将无法工作，因为他们的结果不区分模块都包含在超类前面的模块中。换句话说，他们无法区分以下两种情况：
 
 
  
    M 被添加到 B  
  end 
 class B<一个; end 
 module M; end 
 A.prepend M 
 
 B.ancestors＃=> [B，M，A，Object，Kernel，BasicObject] 
 B< => M＃=> -1 
 B.included_modules＃=> [M，Kernel] 
  
 
 
    M 包含在 B  
  end 
 class B<一个; end 
 module M; end 
 B.include M 
 
 B.ancestors＃=> [B，M，A，Object，Kernel，BasicObject] 
 B< => M＃=> -1 
 B.included_modules＃=> [M，Kernel] 
  
 
 
 
 
 
解决方案
  mixed_in = B.included_modules [0 ...- B.superclass.included_modules.size] 
 prepended = B.ancestors.take_while {| ancestor | ancestor！= B} 
 included = mixed_in  -  prepended 
  
 
How can I get an array of modules included in a class, excluding those that slipped in through inheritance?
Notice that ancestors, <=>, included_modules will not work because their results do not distinguish modules that are included from modules that are prepended in a superclass. In other words, they cannot distinguish the following two cases:
M is prepended to the superclass of B
class A; end
class B < A; end
module M; end
A.prepend M

B.ancestors # => [B, M, A, Object, Kernel, BasicObject]
B <=> M # => -1
B.included_modules # => [M, Kernel]
M is included in B
class A; end
class B < A; end
module M; end
B.include M

B.ancestors # => [B, M, A, Object, Kernel, BasicObject]
B <=> M # => -1
B.included_modules # => [M, Kernel]
 解决方案 
mixed_in  = B.included_modules[0...-B.superclass.included_modules.size]
prepended = B.ancestors.take_while { |ancestor| ancestor != B }
included  = mixed_in - prepended
                        
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