Ruby Clasess

ruby-talk
1

How do I get all the classes that descend from a parent class ? I found
solution on
http://stackoverflow.com/questions/2393697/look-up-all-descendants-of-a-class-in-ruby.

But I want to know, is there a standard method or not?

···

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2

No there is not.

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3

class Animal

  def self.inherited(subclass)
    children << subclass
  end

  def self.children
    @children ||= []
  end

  def self.descendants
    children.map do |child|
      [child].concat child.descendants
    end.flatten
  end

end

Dog = Class.new Animal
Cat = Class.new Animal
Tabby = Class.new Cat

RUBY_VERSION # => "1.9.2"
Animal.children # => [Dog, Cat]
Animal.descendants # => [Dog, Cat, Tabby]

Cat.descendants # => [Tabby]

4

7stud -- wrote in post #1000123:

No there is not.

THX

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5

Accidentally pasted the code over the entire response >.<

I meant to say you could whip something up without too much effort (as 7stud
said, there is no standard way).

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On Sun, May 22, 2011 at 12:11 PM, Josh Cheek <josh.cheek@gmail.com> wrote:

class Animal

  def self.inherited(subclass)
    children << subclass
  end

  def self.children
    @children ||=
  end

  def self.descendants
    children.map do |child|
      [child].concat child.descendants
    end.flatten
  end

end

Dog = Class.new Animal
Cat = Class.new Animal
Tabby = Class.new Cat

RUBY_VERSION # => "1.9.2"
Animal.children # => [Dog, Cat]
Animal.descendants # => [Dog, Cat, Tabby]

Cat.descendants # => [Tabby]