>>>>> "K" == KONTRA Gergely <kgergely / mlabdial.hit.bme.hu> writes:

K> I except MyClass.instances to give me an array [a,b]
K> Or I would be happy, if I can do
K> MyClass.each{|a| ... }

 Look at ObjectSpace::each_object

K> Has ruby a set type?

 1.8 has a library set.rb


Guy Decoux