You can do whatever you want. You just need to prove that it is correct. I guess I wasn't as clear as I hoped I would be. I don't think the Array indexing issu

You can do whatever you want. You just need to prove that it is correct. I guess I wasn't as clear as I hoped I would be. I don't think the Array indexing issue can be dealt with by (just) improving its interface specification. I think the proper fix for this is beyond what can reasonably be done in any language that doesn't come with a notion of correctness and proof.