Sat Dec 31 12:33:47 EST 2011

Generalizing array instead

Going in loops again..  Why is it again that this can't be expressed
as an ordinary Array?  What about the following?  This expresses more
directly that a tree of arrays is also an array.

  instance Array m r a (L t) => Array m r (L' a) t

Is there anything new?  Yes: I did not allow trees of arrays before.

This can't be expressed directly due to a kind mismatch.  So this
needs a transformer / isomorphism that I don't see how to express..