Doryen VS mypy

Aw, thanks friend! Just using libtcod and a handful of basic ones for maths-related stuff and saving/loading, nothing remotely specialist on that side of things. All the code for generating graphics for instance is based on libtcod, but definitely using the functionality in novel ways!

See the libtcod repo for everything. The contributing file has info on how to configure CMake. Feel free to make an issue, discussion, or PR there if any changes are needed or you have anything you want to ask about.

libtcod | GitHub | Issues | Forum | Changelog | Documentation | Template

Today I'm back to working on Pataro, the roguelike built on libtcod that made up much of my Hacktoberfest efforts. I had been assigned to an issue requesting the addition of serialization and deserialization, but unfortunately ran out of time and wasn't able to finish the former or start the latter. I ran into issues with Cereal, and had a hard time figuring out the structure of the program and how to go about implementing serialization for all the relevant components. At the end of that attempt I mentioned that if I were to try again I'd start by testing out Cereal separately and getting a handle on that before trying to implement it in Pataro - so that's what I'm doing today.

One of the biggest problems I've faced while tackling this has been figuring out the structure of the program. I've never worked on a game before so the structure of how all the different pieces fit together is alien to me, but I've been slowly figuring it out over the past days and weeks. After getting in touch with the developer of (Pataro)[https://github.com/SuperFola/pataro] and reading tutorials on developing with (libtcod)[https://github.com/libtcod/libtcod] I think I have a better idea of how to approach it.

This month I'm working on participating in Hacktoberfest, starting with contributing to a roguelike game called Pataro built on the libtcod roguelike development library. I chose to work on adding a serialization mechanism to save the player's progress and so far it's involved a lot of new and challenging processes. I haven't completed my work yet but wanted to start sharing progress on my learning and status.

If you're willing to stick to the terminal for now, libtcod is popular for tutorials on building roguelikes.

The same thing happened to me as happened to you, I also hate Libtcod, and it's because of its poor code interpolation with C++ and its null documentation, so I also decided to create a Fork and work on it, the result, an ASCII render with a simple to use, scalable, clean and maintainable interface.

libtcod | GitHub | Issues | Forum | Changelog | Documentation

Like you, I also had the same problem when reviewing the Libtcod code, so I decided to write an engine based on the Libtcod 1.5 code, I am currently still working on it, and I plan to add elements to it to make interfaces using flexbox layout.

It's got type annotations and mypy has a discussion about it here as well: https://github.com/python/mypy/issues/1282

There is already an AOT compiler for Python: Nuitka[0]. But I don't think it's much faster.

And then there is mypyc[1] which uses mypy's static type annotations but is only slightly faster.

And various other compilers like Numba and Cython that work with specialized dialects of Python to achieve better results, but then it's not quite Python anymore.

[0] https://nuitka.net/

[1] https://github.com/python/mypy/tree/master/mypyc

In Python there is MyPy that can help with this. https://www.mypy-lang.org/

It's funny you should say this.

Reading this article prompted me to future-proof a program I maintain for fun that deals with time; it had one use of utcnow, which I fixed.

And then I tripped over a runtime type problem in an unrelated area of the code, despite the code being green under "mypy --strict". (and "100% coverage" from tests, except this particular exception only occured in a "# pragma: no-cover" codepath so it wasn't actually covered)

It turns out that because of some core decisions about how datetime objects work, `datetime.date.today() < datetime.datetime.now()` type-checks but gives a TypeError at runtime. Oops. (cause discussed at length in https://github.com/python/mypy/issues/9015 but without action for 3 years)

One solution is apparently to use `datetype` for type annotations (while continuing to use `datetime` objects at runtime): https://github.com/glyph/DateType

PEP 695 is great. I've been using mypy every day at work in last couple years or so with very strict parameters (no any type etc) and I have experience writing real life programs with Rust, Agda, and some Haskell before, so I'm familiar with strict type systems. I'm sure many will disagree with me but these are my very honest opinions as a professional who uses Python types every day:

* Some types are better than no types. I love Python types, and I consider them required. Even if they're not type-checked they're better than no types. If they're type-checked it's even better. If things are typed properly (no any etc) and type-checked that's even better. And so on...

* Having said this, Python's type system as checked by mypy feels like a toy type system. It's very easy to fool it, and you need to be careful so that type-checking actually fails badly formed programs.

* The biggest issue I face are exceptions. Community discussed this many times [1] [2] and the overall consensus is to not check exceptions. I personally disagree as if you have a Python program that's meticulously typed and type-checked exceptions still cause bad states and since Python code uses exceptions liberally, it's pretty easy to accidentally go to a bad state. E.g. in the linked github issue JukkaL (developer) claims checking things like "KeyError" will create too many false positives, I strongly disagree. If a function can realistically raise a "KeyError" the program should be properly written to accept this at some level otherwise something that returns type T but 0.01% of the time raises "KeyError" should actually be typed "Raises[T, KeyError]".

* PEP 695 will help because typing things particularly is very helpful. Often you want to pass bunch of Ts around but since this is impractical some devs resort to passing "dict[str, Any]"s around and thus things type-check but you still get "KeyError" left and right. It's better to have "SomeStructure[T]" types with "T" as your custom data type (whether dataclass, or pydantic, or traditional class) so that type system has more opportunities to reject bad programs.

* Overall, I'm personally very optimistic about the future of types in Python!

[1] https://github.com/python/mypy/issues/1773

# is fixed: https://github.com/python/mypy/issues/12987.

You probably already know but you can add type hints and then check for consistency with https://github.com/python/mypy in python.

Modern Python with things like https://learnpython.com/blog/python-match-case-statement/ + mypy + Ruff for linting https://github.com/astral-sh/ruff can get pretty good results.

I found typed dataclasses (https://docs.python.org/3/library/dataclasses.html) in python using mypy to give me really high confidence when building data representations.