Suppose the following code:
class A
end
a = A.new
As = class << a
self
end
# or:
# As = a.singleton_class
Is there some way to get a from As?
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MMSequeira
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2I don't know what you're doing there, but I'm almost sure that it's terribly wrong way to achieve the result. What is it that you're ultimately trying to achieve? – Sergio Tulentsev Nov 25 '12 at 15:34
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Just learning about the dark corners of Ruby. Not trying to solve any practical problems. – MMSequeira Nov 25 '12 at 15:47
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1Well, in that case, forget what you saw here and never ever do it in a real project :) – Sergio Tulentsev Nov 25 '12 at 15:48
4 Answers
3
Here's a trick for you:
class A
end
a = A.new
As = a.singleton_class
a2 = ObjectSpace.each_object.select{|obj| obj.singleton_class == As}.first
a2 == a # => true
Sergio Tulentsev
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I think it is simple:
ObjectSpace.each_object(As).first
# => #<A:0x000000029a7c50>
sawa
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This is just educated guessification on my part so YMMV, but I think "a" needs to be defined as a class variable (ie. "@@a = A.new") and then you would have the appropriate accessor method to return the class instance.
That being said, however, have you considered using the Singleton module (assuming you're on 1.9.3)?
mjbraun
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I'm talking about Ruby eigenclasses, also known as singleton classes, confusingly. This question is not about the singleton pattern. – MMSequeira Nov 25 '12 at 15:50
