That's right.My mistake comes from implicitely thi...

2008-10-07T11:51:00.000-02:00

That's right.

My mistake comes from implicitely thinking that include or extend where not much than this:

ancestor_chain.add(module)

So it seems they are not as dumb and it's not possible to do weird things like [X, X, X, Object]. They don't just follow orders.

> puts a.foo #=> A#foo (and not X#foo!!!!!!!)Calli...

2008-10-07T01:07:00.000-02:00

> puts a.foo #=> A#foo (and not X#foo!!!!!!!)

Calling .ancestors should have given you a hint but to quote Programming Ruby "mixed-in modules effectively behave as superclasses". If you changed your 'foo' method definition to:

def foo
super rescue "A#foo"
end

You'll see X#foo as you expect after mixing in X.

This also may help explain why Ruby ignores your a.extend X since X is already mixed in and behaving as a superclass.

Comments on Daniel Cadenas: One thing to keep in mind when extending Ruby clas...

That's right.My mistake comes from implicitely thi...

> puts a.foo #=> A#foo (and not X#foo!!!!!!!)Calli...