Scala.js
mypy
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Scala.js | mypy | |
---|---|---|
34 | 112 | |
4,538 | 17,506 | |
0.5% | 1.4% | |
9.0 | 9.7 | |
10 days ago | 6 days ago | |
Scala | Python | |
Apache License 2.0 | MIT License |
Stars - the number of stars that a project has on GitHub. Growth - month over month growth in stars.
Activity is a relative number indicating how actively a project is being developed. Recent commits have higher weight than older ones.
For example, an activity of 9.0 indicates that a project is amongst the top 10% of the most actively developed projects that we are tracking.
Scala.js
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The dangers of single line regular expressions
`$` does mean end of input in Java, unless you explicitly ask for multiline mode. In the latter case it means `(?=$|\n)` if also in Unix-lines mode, and the horrible `(?=$|(?I wrote a compiler from Java regex to JavaScript RegExp, in which you'll find that particular compilation scheme [1].
[1] https://github.com/scala-js/scala-js/blob/eb160f1ef113794999...
- Typescript FP Job?
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Reconnecting with Scala. What's new?
Links: - https://dotty.epfl.ch/ - https://scala-native.org/en/stable/ - https://www.scala-js.org/ - https://typelevel.org/ - https://zio.dev/ - https://github.com/scala-native/scala-native/pull/3120 - https://github.com/lampepfl/dotty/pull/16517 - https://dotty.epfl.ch/docs/reference/experimental/index.html - https://scala-cli.virtuslab.org/ - https://scalameta.org/metals/ - https://docs.scala-lang.org/scala3/guides/migration/compatibility-intro.html - https://www.scala-lang.org/blog/2023/04/18/faster-scalajs-development-with-frontend-tooling.html - https://www.scala-lang.org/blog/2022/08/17/long-term-compatibility-plans.html
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Rust on Espressif chips – 2023 Roadmap
> Scala choices were directly dictated by JVM
Initially, yes. But Scala has evolved beyond the JVM, with Scala.js [1] being rock-solid, and Scala Native [2] under development. Neither are truly hampered by the initial JVM roots of Scala.
> Scala gives you a better horse
Weird analogy ;)
[1] https://www.scala-js.org/
- 10 years of Scala.js
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Looking for an alternative to Javascript
Have you had a look at Scala.js yet? Also see "Scala.js for JavaScript developers." and "Tour of Scala."
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Contrary to popular belief, Scala is actually a quite small and simple language
What does that have to do with language size? It also compiles to js https://www.scala-js.org/ and native https://scala-native.org/en/stable/
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Switch JS job for Scala internship?
Here's a hybrid option: Scala.js. Yes, it is about building web applications but in Scala. You can retain the HTML/CSS/JS knowledge you have but build web applications from a typesafe and powerful language: Scala
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Dropping Scala 2.11 support in Scala.js and Scala Native
The compiler crash in question affects another feature that we would like to merge for the benefit of all users, namely https://github.com/scala-js/scala-js/pull/4735. Keeping 2.11 means that testing and shipping that feature is much more difficult, even for 2.12+ users only. It's not just "to fix a compiler crash".
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Windows decide whether your computer has limited or full Internet access
TS is more in the "mixed feelings" department, imho.
I would take Scala.js anytime instead. (If I would need to do front-end ever again).
https://www.scala-js.org/
mypy
- The GIL can now be disabled in Python's main branch
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Polars – A bird's eye view of Polars
It's got type annotations and mypy has a discussion about it here as well: https://github.com/python/mypy/issues/1282
- Static Typing for Python
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Python 3.13 Gets a JIT
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
- Introducing Flask-Muck: How To Build a Comprehensive Flask REST API in 5 Minutes
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WeveAllBeenThere
In Python there is MyPy that can help with this. https://www.mypy-lang.org/
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It's Time for a Change: Datetime.utcnow() Is Now Deprecated
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
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What's New in Python 3.12
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
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Mypy 1.6 Released
# is fixed: https://github.com/python/mypy/issues/12987.
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Ask HN: Why are all of the best back end web frameworks dynamically typed?
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.
What are some alternatives?
scalajs-react - Facebook's React on Scala.JS
pyright - Static Type Checker for Python
js-scala - js.scala: JavaScript as an embedded DSL in Scala
ruff - An extremely fast Python linter and code formatter, written in Rust.
awesome-wasm-langs - 😎 A curated list of languages that compile directly to or have their VMs in WebAssembly
pyre-check - Performant type-checking for python.
sri
black - The uncompromising Python code formatter
React4s - Production ready React wrapper for Scala.js - composable lifecycle - no memoization, no macros, no implicits.
pytype - A static type analyzer for Python code
Laminar - Simple, expressive, and safe UI library for Scala.js
pydantic - Data validation using Python type hints