import kernel

redef interface Object

	fun foo
	do
		'a'.output
		'\n'.output
	end
end

interface M
	redef fun foo
	do
		'm'.output
		super
	end
end

class B
	init cb
	do
		'B'.output
	end

	redef fun foo
	do
		'b'.output
		super
	end
end

interface N
	redef fun foo
	do
		'n'.output
		super
	end
end

class O
special M
special B
	redef fun foo
	do
		'o'.output
		super
	end
end

class P
special B
special N
	redef fun foo
	do
		'p'.output
		super
	end
end

class Q
#alt0#special M
#alt0#special B
#alt0#special N

#alt1#special O
#alt1#special N

#alt2#special M
#alt2#special P
	
#alt3#special O
#alt3#special P
	redef fun foo
	do
		'q'.output
		super
	end
end

(new B.cb).foo
(new O.cb).foo
(new P.cb).foo
(new Q.cb).foo