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I agree that it sounds really stupid up front, but it's done when you're just you modeling the constraints of the problem. I've found that it saves a lot of ti

I agree that it sounds really stupid up front, but it's done when you're just you modeling the constraints of the problem. I've found that it saves a lot of time in debugging and silly mistakes later. For types with invariants, you just add the `Invariant` aspect and then the type invariant gets checked automatically when passed as a parameter. Combined with built-in pre/post conditions, I've found that these sort of automatically inserted checks give me a lot of confidence, and allow significant embedding of conceptual and domain knowledge during development.

zbentley 4y ago
If you like this style of programming but use Python for your day-to-day, check out typeguard; it provides runtime assertions for parts of the Python type annotation system similar to "Invariant". As with many tools, there are caveats. It's often surprisingly slow (so avoid using it on hot paths, or only turn it on during your testing/pre-production runs) and can't type-check everything (e.g. callables). But it's still pretty nice and requires minimal effort to use! https://pypi.org/project/typeguard/ https://pypi.org/project/typeguard/