Hi all, It has been some time, but I do have an update regarding this proposed feature. I thought it would be helpful to flesh out some parts of a possible implementation to learn what can be spelled reasonably in NumPy. Mark Wiebe helped out greatly in navigating the NumPy code codebase. Here is a link to my branch with this code; https://github.com/bryevdv/numpy/tree/enum and the updated NEP: https://github.com/bryevdv/numpy/blob/enum/doc/neps/enum.rst Not everything in the NEP is implemented (integral levels and natural naming in particular) and some parts definitely need more fleshing out. However, things currently work basically as described in the NEP, and there is also a small set of tests that demonstrate current usage. A few things will crash python (astype especially). More tests are needed. I would appreciate as much feedback and discussion as you can provide! Thanks, Bryan Van de Ven