Re: diff lib
I think we're doing two different kinds of diff. My library takes sequences `a` and `b` and returns a sequence of "spans" (i.e., insert/delete/replace a from to, b from to) that if applied to `a` would transform it into `b`. This is explained in the Python [difflib docs](https://docs.python.org/3/library/difflib.html).
Re: diff lib
I have an advanced differ for arbitrary Nim types if you want to study how to transform yours into macro. My use-case is for a test suite so I throw an exception as soon as there is a mismatch. [https://github.com/status-im/nim-beacon-chain/blob/9050db7b/tests/helpers/debug_state.nim#L39-L114](https://github.com/status-im/nim-beacon-chain/blob/9050db7b/tests/helpers/debug_state.nim#L39-L114)
diff lib
I've ported Python's difflib's sequence matcher to pure Nim: [diff](https://github.com/mark-summerfield/diff). It can be used to see the differences between any two sequences of items that support `==` and `hash()` (string, char, or any custom item type with the necessary support).
