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Python developers are embracing type hints

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Re: Python developers are embracing type hints

#51

Post by mjr00 »

pdonis wrote: post #36
mjr00 wrote: post #33

Earlier quoted context omitted.

As the top comment says, if you don't know or want to define the type just use Any. That's what it's there for. That entire Reddit post is a clueless expert beginner rant about something they don't really understand, unfortunate that it's survived as long as it has or that anyone is taking it as any sort of authoritative argument just because it's long.

> if you don't know or want to define the type That's not the issue the reddit post is raising. The reddit post is pointing out that what a "type" is is not as simple as it looks. Particularly in a language like Python where user-defined types proliferate, and can add dunder methods that affect statements that involve built-in operations. "Just use Any" doesn't solve any of those problems. > just use Any. All the abo…

The Reddit post falls under the case of "don't know" the type. If you want to allow users to pass in any objects, try to add and fail at runtime... that's exactly what Any is for.

But the entire post is built upon the premise that accepting all types is good API design. Which it isn't, at all.

Re: Python developers are embracing type hints

#52

Post by AlienRobot »

Spivak wrote: post #28
scuff3d wrote: post #22

Earlier quoted context omitted.

It's not even close compared to working with Java or Go or any language built with static typing in mind. To be clear, I'm not opposed to type hints. I use them everywhere, especially in function signatures. But the primary advantage to Python is speed (or at least perceived speed but that's a separate conversation). It is so popular specifically because you don't have to worry about type checking and can just move.…

But TypeScript erases (its) types at runtime, exactly like Python. Python is Python's TypeScript. Whether you want TS or JS-like semantics is entirely dependent on whether you use a type checker and whether you consider its errors a build breaker.

Typescript requires a compiler to produce valid Javascript. Python 3 shoved types into Python 3 without breaking backwards compatibility I think.

You would never have typing.TYPE_CHECKING to check if type checking is being done in TypeScript, for example, because type hints can't break Javascript code, something that can happen in Python when you have cyclic imports just to add types.

Re: Python developers are embracing type hints

#53

Post by jmward01 »

Type hints in python are just that, hints. Use them to help with clarity but enforcing them and requiring them everywhere generally leads to the worst of all worlds. Lots of boilerplate, less readable code and throwing away many of the features that make python powerful. Use the best language for the job and use the right language features at the right time. I see too many black or white arguments in the developer community, there is a middle ground and the best code is almost always written there.

Re: Python developers are embracing type hints

#54

Post by dandiep »

AlienRobot wrote: post #49
tecoholic wrote: post #35

I love typing in Python. I learnt programming with C++ and OOPs. It was freeing when I took up Python to note care about types, but I have come to enjoy types as I got older. But, boy have we gone overboard with this now? The modern libraries seem to be creating types for the sake of them. I am drowning in nested types that seem to never reach native types. The pain is code examples of the libraries don’t even show t…

My love for python was critically hurt when I learned about typing.TYPE_CHECKING. For those unaware, due to the dynamic nature of Python, you declare a variable type like this foo: Type This might look like Typescript, but it isn't because "Type" is actually an object. In python classes and functions are first-class objects that you can pass around and assign to variables. The obvious problem of this is that you can…

Isn’t this solved in 3.14/PEP-649?

Re: Python developers are embracing type hints

#56

Post by analog31 »

dandiep wrote: post #54
AlienRobot wrote: post #49

Earlier quoted context omitted.

My love for python was critically hurt when I learned about typing.TYPE_CHECKING. For those unaware, due to the dynamic nature of Python, you declare a variable type like this foo: Type This might look like Typescript, but it isn't because "Type" is actually an object. In python classes and functions are first-class objects that you can pass around and assign to variables. The obvious problem of this is that you can…

Isn’t this solved in 3.14/PEP-649?

At last, Pi-thon.

Re: Python developers are embracing type hints

#57

Post by zahlman »

mjr00 wrote: post #51
pdonis wrote: post #36

Earlier quoted context omitted.

> if you don't know or want to define the type That's not the issue the reddit post is raising. The reddit post is pointing out that what a "type" is is not as simple as it looks. Particularly in a language like Python where user-defined types proliferate, and can add dunder methods that affect statements that involve built-in operations. "Just use Any" doesn't solve any of those problems. > just use Any. All the abo…

The Reddit post falls under the case of "don't know" the type. If you want to allow users to pass in any objects, try to add and fail at runtime... that's exactly what Any is for. But the entire post is built upon the premise that accepting all types is good API design. Which it isn't, at all.

> But the entire post is built upon the premise that accepting all types is good API design. Which it isn't, at all.

Was Tim Peters also wrong way back in the day when he counseled Guido van Rossum to allow floats to be added to integers without a cast, like other popular languages?

Re: Python developers are embracing type hints

#58

Post by pansa2 »

zahlman wrote: post #55

It's the other way around, IMO: people who think the language should at least have type hints are now more willing to use it, now that there's better tooling for checking those hints.

Yes. And people who preferred the language (and its culture) before the "fundamental change" of adding type hints are now less willing to use it.

Re: Python developers are embracing type hints

#59

Post by zahlman »

AlienRobot wrote: post #49
tecoholic wrote: post #35

I love typing in Python. I learnt programming with C++ and OOPs. It was freeing when I took up Python to note care about types, but I have come to enjoy types as I got older. But, boy have we gone overboard with this now? The modern libraries seem to be creating types for the sake of them. I am drowning in nested types that seem to never reach native types. The pain is code examples of the libraries don’t even show t…

My love for python was critically hurt when I learned about typing.TYPE_CHECKING. For those unaware, due to the dynamic nature of Python, you declare a variable type like this foo: Type This might look like Typescript, but it isn't because "Type" is actually an object. In python classes and functions are first-class objects that you can pass around and assign to variables. The obvious problem of this is that you can…

> that isn't going to work if you try to use type hints in python because you're going to end up with a cyclic import. More specifically, you don't need cyclic imports in Python normally because you don't need the types, but you HAVE to import the types to add type hints, which introduces cyclic imports JUST to add type hints.

Yes, `typing.TYPE_CHECKING` is there so that you can conditionally avoid imports that are only needed for type annotations. And yes, importing modules can have side effects and performance implications. And yes, I agree it's ugly as sin.

But Python does in fact allow for cyclic imports — as long as you're importing the modules themselves, rather than importing names `from` those modules. (By the way, the syntax is the other way around: `from ... import ...`.)

https://stackoverflow.com/questions/744373/

Re: Python developers are embracing type hints

#60

Post by zahlman »

circadian wrote: post #19

I really love Python for it's expedience, but type hints still feel like they don't belong in the language. They don't seem to come with the benefits of optimisation that you get with static typed languages. As someone who uses C and Julia (and wishes they had time for Rust), introducing solid typing yields better end results at a minimum, or is a requirement at the other end of the scale. The extra typing clarificat…

> They don't seem to come with the benefits of optimisation that you get with static typed languages

They don't. And cannot, for compatibility reasons. Aside from setting some dunders on certain objects (which are entirely irrelevant unless you're doing some crazy metaprogramming thing), type annotations have no effect on the code at runtime. The Python runtime will happily bytecode-compile and execute code with incorrect type annotations, and a type-checking tool really can't do anything to prevent that.

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