From: Christian Szegedy <szegedy@...>
Date: 2002-09-06T20:10:27+09:00
Subject: Re: Class variables and inheritance

Philipp Meier wrote:
> Hallo rubyers,
> 
> I'm a little puzzled with Class variables (@@foo) and inheritance:
> 
> class Super
> 	@@foo = []
> 
> 	def self.manipulate(arg)
> 		@@foo << arg
> 	end
> 
> 	def get_foo
> 		@@foo
> 	end
> end
> 
> class Sub1 < Super
> 
> 	manipulate "first"
> 
> end
> 
> class Sub2 < Super
> 	manipulate "second"
> end
> 
> Sub1.new.get_foo # => ["first","second"], wanted "first"
> Sub2.new.get_foo # => ["first","second"], wanted "second"
> 

How about this?

class A

   def self.add(x)
     (@foo||=[])<<x
   end

   def self.get
     (@foo||=[])
   end

   def get
     type.get
   end
end

class A1 < A
   add("1")
end

class A2 < A
   add("2")
end

puts(A1.new.get.join(","))
puts(A2.new.get.join(","))


Best regards, Christian