Hard to conceive of a case where that would occur. Can you think of one?
The implication of what you're saying seems to be that if you're concerned about some kind of correctness you should be writing unit tests anyway and not being so fussed about type checking in a language like Python. I suppose if you are strictly following TDD that might work, but in all other cases type checks give you feedback much more quickly than unit tests ever can. I guess I don't understand.
No, I was correct. Briefly, my question was "why is static typing good?" and the answer given was "static typing is good because it makes development easier." To the extent that "good" here just means "makes development easier" (and I think that is a lot of what "good" means in this context) then the answer I received was question begging to precisely that extent. Which is why I said "... to an extent." The conclusion was not quite assumed but a pretty similar conclusion was.
I can see how it appeared that I was using the phrase in the incorrect way! That usage bothers me too, and I am attentive to it.
What is an example of a compiler that flat out refuses to run (compile) your code? Obviously Python is not an example. The other language I know best is Rust, where as I understand the compiler doesn't refuse to compile your code, it cannot compile your code. Is there a language where the compiler could compile your code but refuses to do so unless the types are all correct?
No offense, but this sounds like user error. I rarely have irrelevant type warnings. If I do, it suggests something is wrong with my design.
If you declare a function parameter as `foo: int = None`... that is just an incorrect declaration. Of course a variable annotated as `int` can take a `None` value, but that is because any variable can take any type in Python. Within the Python type (annotation) system it is simply the case that an `int` and an `int | None` are two different things, as they are in other languages (eg Rust's `T` vs `Option<T>` types).
Mypy used to support the "implicit optional" feature you describe but now you must make nullable arguments explicitly optional. This is in line with Python's "explicit is better than implicit" design philosophy. In any case, how long does it take you to just type `foo: int | None = None`? Or you could re-enable the old behavior to allow implicit optionals with `--implicit-optional` or the corresponding config file option. It seems like you just need to configure mypy to match your preferences rather than fighting with its defaults.
To return to the broader point, I'm unsure what an "irrelevant type warning" is, but I suspect that has something to do with my lack of appreciation for dynamic typing. Can you give an example that isn't just a complaint about typing an extra 6 characters or about mypy being misconfigured for your preferences?
But you can achieve #1 with typing.Protocol in type-annotated Python and traits in Rust. Fitting the "strict definition" sounds like nominal typing but you can opt in to explicit duck typing or structural typing while still being typed. (Someone correct me if I'm using these terms incorrectly.) In short you can still encode a lot of flexibility with types without just abandoning them alltogether.
And with #2, you can get that with static typing too... Let's say a method accepts an instance of an object `Foobar`. I can change the definition of `Foobar` ("change what shape [my] data is") without having to change type annotations everywhere.
I agree with you, I guess, that I find the steel man position unconvincing.
That would seem to be begging the question to an extent. Why does dynamic typing lead to lower development effort? I mostly write Python and make heavy use of type hints. With LSP set up, mypy informs me immediately of any potential type errors which makes development way easier for me.
Just saying "dynamic typing is easier" doesn't do it for me without further qualification since that statement doesn't conform to my own experience.
Even better, run `mypy` as part of your LSP setup and you don't even need to wait to run `mypy` to see type errors! If I make a mistake I want to be notified immediately.
I would love to read the steel man case for dynamic typing, but "static typing is for people who need therapy" isn't doing it for me. Anyone have something to recommend so I can understand the intended benefits of dynamic typing?
Why would I want to do that? I'm rarely ingesting arbitrary JSON. Rather I'm designing my data structures in a sensible way and then maybe serializing them to JSON. Just because JSON can represent heterogenous lists doesn't mean it is a good idea to use heterogenous lists in my programs.
Agreed, I was just joking. I understand heterogenous lists are possible with Python, but with the use of static type checking I feel like its pretty rare for me to have heterogenous lists unless its duck typing.
Well, I'm one of those people, and I feel that I rarely do this. Except if I have a list of different objects that implement the same interface, as another commenter mentioned.
I'm satisfied with Mypy but curious to someday try other type checkers. Pyright is on the list.