From: Rick DeNatale <rick.denatale@...>
Date: 2008-03-09T21:50:59+09:00
Subject: Re: Redefine a class with same name

On 3/9/08, ts <decoux@moulon.inra.fr> wrote:
> >>>>> "M" == Martin Boese <boesemar@gmx.de> writes:
>
>  M> Is there any way to to remove the definition of a class so I can reuse its
>  M> name? Like below I'd like to reuse the name 'A' but since it's already
>  M> defined with a different superclass I get a 'TypeError: superclass mismatch
>  M> for class A'.
>
>   Just remove the constant
>
>  M> class A < X
>  M> end
>
>    Object.send(:remove_const, :A)
>
>  M> class A < Y
>  M> end

Keep in mind though, that this only removes the binding between the
constant and the class, it doesn't actually allow you to change the
old class, and any existing instances will still be instances of the
old class not the new one:

k$ irb
irb(main):001:0> class A
irb(main):002:1>   def foo
irb(main):003:2>     end
irb(main):004:1> end
=> nil
irb(main):005:0> a = A.new
=> #<A:0x6e578>
irb(main):006:0> a.foo
=> nil
irb(main):007:0> Object.send(:remove_const, :A)
=> A
irb(main):008:0> a.foo
=> nil
irb(main):009:0> a.class
=> A
irb(main):010:0> A
NameError: uninitialized constant A
        from (irb):10
irb(main):011:0> class A
irb(main):012:1> def bar
irb(main):013:2> end
irb(main):014:1> end
=> nil
irb(main):015:0> a.bar
NoMethodError: undefined method `bar' for #<A:0x6e578>
        from (irb):15
irb(main):016:0>


-- 
Rick DeNatale

My blog on Ruby
http://talklikeaduck.denhaven2.com/