On Thu, Jun 05, 2003 at 05:36:00PM +0900, ts wrote:
>  What do you think that undef_method do ?

Well, I don't know exactly :-) It doesn't define a dummy method if one does
not already exist:

irb(main):001:0> class A
irb(main):002:1> undef_method :val1
irb(main):003:1> end
NameError: undefined method `val1' for class `A'
        from (irb):2:in `undef_method'
        from (irb):2

Regards,

Brian.