Is there any way of completely remove a class object's methods instead of
extending the class?

I'd like to be able to do:

class A
   attr :t
   def initialize
       @t = 1
   end
end

a = A.new
puts a.t   # => 1

# Not extending... redefining here....
class A
   attr :x
   def initialize
       @x = 3
   end
end


a = A.new
puts a.x # => 3
puts a.t # => error, instead of outputing nil

I'm finding the above to be a major pain when debugging and prototyping new
code in either irb or an embedded ruby, every time I reload a library.