[Parrot-users] Class.add_vtable_override

[Andrew Whitworth]

the "add_vtable_override" vtable and method have a restriction which
prevents the user from setting the same vtable more than once. Once
you set a vtable override on a class, you can't use that interface to
modify it. There are other ways to modify it, so it's not a hard
restriction.

I suggest that Parrot's Class PMC should not be enforcing that kind of
restriction, that's the kind of thing that the HLL should be in
control of.

I've created a branch whiteknight/add_vtable_override to remove that
restriction and run tests. All tests pass in Parrot master (sans one
test for that specific exception, which I removed). I am going to do
some testing in various HLLs to see if this branch causes any
problems. If anybody has some spare cycles, I would appreciate help
testing various HLLs to see which, if any, are affected.

Thanks,

--Andrew Whitworth