Specifications for ERC721

[alex-chambet]

I'm currently writing the specifications for ERC721 tokens. I've been able to specify: balanceOf, ownerOf, approve and getApproved. However, when trying to specify safeTransferFrom, I ran into issues and I'm now kinda stuck on them.

Specifically, I'm now focused on making safeTransferFrom works in the success cases (i'll do the failure afterwards). In the case where FROM_ID =/= TO_ID, everything works, but in the case where FROM_ID == TO_ID it does not work and I'm clueless about that.

Here is my gist of the specifications and the Solidity source code I used.

If someone can have a look and tell why it fails, it'll be greatly appreciated!