Comment by mjr00
3 months ago
> Following the general stupidness of the post: they are now unable to do that because a security consultant said they have to enable and can not break RUFF rule ANN401: https://docs.astral.sh/ruff/rules/any-type/
Okay, then your function which is extremely generic and needs to support 25 different use cases needs to have an insane type definition which covers all 25 use cases.
This isn't an indictment of the type system, this is an indictment of bad code. Don't write functions that support hundreds of input data types, most of which are unintended. Type systems help you avoid this, by the way.
> Don't write functions that support hundreds of input data types
But by it's nature, duck typing supports an unbounded number of input types and is what Python was built on.
You've already decided duck typing is wrong and strict type adherence is correct, which is fine, but that doesn't fit the vast history of Python code, or in fact many of the core Python libraries.
> But by it's nature, duck typing supports an unbounded number of input types and is what Python was built on.
You're trying to shove a square peg into a round hole. It's not about right or wrong. Either you want your function to operate on any type, attempt to add the two values (or perform any operation which may or may not be supported, i.e. duck typing), and throw an runtime error if it doesn't work--in which case you can leave it untyped or use `Any`--or you want stronger type safety guarantees so you can validate before runtime that nobody is calling your method with incorrect arguments, in which case you have to represent the types which you accept somehow.
If you want to have a method that's fully duck typed, you're supposed to use `Any`. That's exactly why it exists. Inventing contrived scenarios about how you can't use `Any` is missing the point. It's like complaining C doesn't work if you're not allowed to use pointers.
You're right that historically Python code was written with duck typing in mind, but now even highly flexible libraries like Pandas have type definition support. The ecosystem is way different from even 5-6 years ago, I can't think of any well-known libraries which don't have good typing support by now.
> You're trying to shove a square peg into a round hole
Yeah, that's literally the point of my Reddit post
Duck typing is great, for example to support a range of numeric inputs - say fixed-precison integers, floats, dynamic precision integers, and numpy arrays, pandas series, tensorflow/pytorch tensor. That duck typing can support functions with unbounded types, dos not mean that it is necessary, not generally sensible, for a particular function to support unbounded types.
Duck typing is great and Python’s type system has powerful support for it. You can for instance restrict a function to only objects with a frobnicate() method, without in any way constraining yourself on which implementation you accept. Type checking plus duck typing is very precise and powerful, and it helps me sleep at night.