From: ts <decoux@...>
Date: 2001-11-02T19:15:39+09:00
Subject: [ruby-talk:24156] Re: Dynamic object type from variable

>>>>> "M" == Matthew Diephouse <fokke_wulf@hotmail.com> writes:

M> class A
M> 	...
M> 	method=(class)
M> 		@var = class.new(self)
M> 	end
M> end

 Well, you can do it with eval, but you can also make weird thing with
 eval. When ruby create a class, it create a constant with the same name
 just retrieve this constant. For example

pigeon% cat b.rb
#!/usr/bin/ruby
class A
   attr_reader :var
   def cmethod=(klass)
      cl = Object
      klass.split('::').each {|l| cl = cl.const_get l }
      @var = cl.new
   end
end

module B
   class C
   end
end

class D
end

a = A.new
a.cmethod = "B::C"
p a.var
a.cmethod = "D"
p a.var
pigeon% 


pigeon% b.rb
#<B::C:0x401b7504>
#<D:0x401b7324>
pigeon% 


Guy Decoux