[ruby-core:62193] [ruby-trunk - Feature #9779] [Open] Add Module#descendents

Issue #9779 has been reported by Shugo Maeda.

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Feature #9779: Add Module#descendents
https://bugs.ruby-lang.org/issues/9779

* Author: Shugo Maeda
* Status: Open
* Priority: Normal
* Assignee: 
* Category: core
* Target version: current: 2.2.0
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Now classes have links to their subclasses, so how about to add Module#descendents?

```ruby
class X
end

class Y < X
end

class Z < Y
end

p X.descendents    #=> [X, Y, Z]

module A
end

module B
  include A
end

module C
  include A
end

p A.descendents    #=> [A, C, B]
```

One of my own use cases is to implement AspectJ like pointcut which matches all subclasses of the given class.

Considerations:

* Should the return value of Module#descendents include self?
* Should the return value of Module#descendents include singleton classes?

I attach a patch, where the return value includes both self and singleton classes.


---Files--------------------------------
0001-Add-Module-descendents.patch (3.75 KB)


-- 
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