Type hints

[nkantar]

Hi, @carltongibson!

First of all, mega thanks for Neapolitan! I’ve looked at it before, but only started using it last night on a small side project, and already love it. The simplicity is beautiful, and the small surface area is a major feature.

The only thing that’s I’m missing are type hints.

I know type hints are not to everyone’s taste. They add a non-trivial amount of syntax and maintenance burden, and Python is certainly very much Python even without them. So, I’m not here to criticize that choice, but to gauge (your) interest in them.

Fortunately there are multiple ways of adding type hints to a project. I myself am aware of three:

1. right in the .py source code
2. in .pyi files living alongside the source code
3. in .pyi files in an entirely separate project

I’ve already started working on option 3 locally, and it’s serving me well. I’d like to see if I can finish it this weekend and publish on PyPI as something like neapolitan-types or neapolitan-stubs. However, it seemed prudent to check in and see if you have a preference for one of the first two options, and redirect my effort if so.

For what that’s worth, I’m fine with all three options. Option 3 is probably the easiest way forward, and converting to option 2 would require minimal effort some day, should we all choose to do so. Option 1, however, is the most “aggressive”, and seems in some ways perhaps counter to the very spirit of Neapolitan, particularly in a world where django-stubs exists. I have some preference for starting with option 3, to avoid affecting development of Neapolitan itself, but welcome all thoughts and feelings.

What say you?

[carltongibson]

Hey @nkantar.

First up, welcome aboard! Glad you're having fun!

Then, yes, option 3 is probably the way to go for now.

Let me quote the mypy docs:

Python is a highly dynamic language and has extensive metaprogramming capabilities. Many popular libraries use these to create APIs that may be more flexible and/or natural for humans, but are hard to express using static types. Extending the PEP 484 type system to accommodate all existing dynamic patterns is impractical and often just impossible.

That's us.

I basically refuse to write my model name five times in three lines declaring a barebones CRUDView just to keep the type checker happy.

To wit, I have a back-burner side project to experiment with a mypy plugin to teach the type checker how Neapolitan works. (If that goes well, note the "if", I'd likely argue that's an approach we could think about for Django too: I don't like the types in Django-stubs, as great as that project is, and as much as I see why they've made the choices they have. Making the best of it. See that quote above.)

I'm not going to inline type annotations until I've progressed that project. But happy to support/watch what you come up with, absolutely!

Make sense?

[nkantar]

That all sounds spot on to me. 👍 I’ll share more when I make some meaningful progress. 😁

[nkantar]

It’s quite early days, and I hope the README makes it clear things aren’t even necessarily correct just yet, but it’s a start: repo + package!