enforce

I've been using enforce for this purpose (https://github.com/RussBaz/enforce). It provides decorators that enable type checking where wanted. This gives the advantage of migrating existing code to type checking at your own pace at least. On a general note I've come across a few cases, when pushing python's type annotations to their limits, that force you to put the type names in string quotes, and that makes the whole thing feel like a hack. It's better than nothing for my use cases, but if I remember correctly both mypy and enforce have problems in common that are probably coming from the way python itself is built, such as self reference in a class definition.

Worth pointing out maybe that MyPy is not a language but a type checker that works with regular Python. I've been getting into the habit of using it on everything I do lately and find it extremely useful. You can even do runtime checking on the types with tools like Enforce [1], and the Molten framework that was posted on here last week [2] uses MyPy typing as a core part of the framework. [1] https://github.com/RussBaz/enforce [2] https://news.ycombinator.com/item?id=18107818

Didn’t know about the enforce library (https://github.com/RussBaz/enforce/blob/master/README.md) — but have been wanting something like this. Thanks for the useful list!