Pyrefly: A new type checker and IDE experience for Python

Post by insane_dreamer » Sat, May 17, 2025, 3:56 PM UTC

aleksanb wrote: post #22

To repeat an earlier comment of mine from the launch of uv on hn (tl; dr: these new type checkers never support django): The way these type checkers get fast is usually by not supporting the crazy rich reality of realworld python code. The reason we're stuck on mypy at work is because it's the only type checker that has a plugin for Django that properly manages to type check its crazy runtime generated methods. I wis…

Post by mdaniel » Sat, May 17, 2025, 4:01 PM UTC

lynndotpy wrote: post #56

doug_durham wrote: post #49

Why is "written in Rust" a feature to be mentioned? Who cares? So my type checker has memory protection and is compiled. I'm not running my type checker on an embedded system or in a mission critical service. It seems kind of like "written in Erlang". I'd prefer to have non-performance critical code for Python written in Python. That way the broader community can support and extend it.

Have you used Rust before? As a user, the speed and safety is nice. But as a developer, Rust projects are easier to hack on and contribute to. That's kind of the whole appeal of Astral. I know Python better than Rust, but it's a lot easier for me to hack on Rust projects. The whole appeal of Astral is that they want to bring Rust-quality tooling to Python.

Post by lynndotpy » Sat, May 17, 2025, 4:07 PM UTC

mdaniel wrote: post #63

lynndotpy wrote: post #56

Earlier quoted context omitted.

Have you used Rust before? As a user, the speed and safety is nice. But as a developer, Rust projects are easier to hack on and contribute to. That's kind of the whole appeal of Astral. I know Python better than Rust, but it's a lot easier for me to hack on Rust projects. The whole appeal of Astral is that they want to bring Rust-quality tooling to Python.

> but it's a lot easier for me to hack on Rust projects That static typing is nice, I wonder if it's going to catch on one day. The amount of energy spent trying to bend dynamically types languages into being real ones is just comical. Even the standard library is barely typed, so they give no fucks https://github.com/python/cpython/blob/v3.13.3/Lib/re/__init... What does it accept? Who knows. What does it return? Do…

Post by adsharma » Sat, May 17, 2025, 4:18 PM UTC

aleksanb wrote: post #22

To repeat an earlier comment of mine from the launch of uv on hn (tl; dr: these new type checkers never support django): The way these type checkers get fast is usually by not supporting the crazy rich reality of realworld python code. The reason we're stuck on mypy at work is because it's the only type checker that has a plugin for Django that properly manages to type check its crazy runtime generated methods. I wis…

  @sqlmodel
  @pydantic
  @dataclass
  class MyModel:
    name: str

Post by neongreen » Sat, May 17, 2025, 4:24 PM UTC

bpshaver wrote: post #57

mcbuilder wrote: post #54

Earlier quoted context omitted.

I feel like 70% of open source projects on GitHub say written in the language that they were written in

I feel like the likelihood that a project will say what language it is written in is much higher if that language is Rust. I like Rust but I do find this trend a little annoying. (Even though I acknowledge that "written in Rust" probably means the tool is relatively new, not buggy, and easy to use.)