On Aug 29, 11:25  ®򮮮 
> Jim Xu wrote:
> > irb(main):171:0> class B < C
> > irb(main):172:1> include A
> > irb(main):173:1> end
> > TypeError: superclass mismatch for class B
> > from (irb):171
> > from :0
>
> Of course you cannot do it, because a moment ago you declared the method
> B as an immediate descendant of Object, and now you want it to be the
> descendant of C. The error has nothing to do with mixins.
>
> irb(main):046:0> class A;end
> => nil
> irb(main):047:0> class B;end
> => nil
> irb(main):048:0> class B<A;end
> TypeError: superclass mismatch for class B
> from (irb):48
> --
> Posted viahttp://www.ruby-forum.com/.

Yes, my mistake. I am still trying to get comfortable that Ruby allows
extending existing classes in runtime... I always thought that when
defining a new class, it points the symbol to a new object instead of
opening up the existing object... (under the same scope of course)