Should there be support for adding phantom types to pyml?

[wu-s-john]

I played around with this library and found it quite nice to play with Python functions. Sadly, I can't leverage the OCaml compiler to different types of PyObject.t (e.g. ints and Nones are considered to be PyObject types). For some cases, it would be helpful to differentiate the types. I was wondering if you have any plans to add this?

[thierry-martinez]

Thank you for this suggestion. I was thinking about this long time ago, but I still don't know what would be the right design for this. I think that one safe path for a type-safe interface would be to keep the Py module as it is for retro-compatibility, and define a typed interface in another module, or in another library depending on pyml. There is another question about how to design the typed interface itself, in particular regarding to None, duck typing, and so on. It would be nice if there could be some correspondence with the type system of mypy.