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Pyre: A performant type-checker for Python 3

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Re: Pyre: A performant type-checker for Python 3

#31

Post by onerandompotato »

IshKebab wrote: post #17
dunefox wrote: post #10

As with package managers, there seem to be half a dozen different, competing type checkers for Python now...

Yeah and even worse they disagree about type errors! We really need a modern Python alternative. I don't know of any that don't give up the REPL / single file script features which are pretty huge advantages of Python to be honest.

Wouldn't Julia be that language? Its fast, supports static typing, and is built from the ground up for machine learning/ data science. It also has a built in REPL.

Re: Pyre: A performant type-checker for Python 3

#32

Post by short_sells_poo »

dunefox wrote: post #10

As with package managers, there seem to be half a dozen different, competing type checkers for Python now...

It's starting to look like the huge embarrassment that is python packaging and environment management. I work with the language every day, and I still have no idea what am I supposed to use between conda, pip, setuptools/setup.py, pyproject, meta.yml, poetry, pipenv, etc...

Conda is so slow that I sometimes wonder if we are being trolled by some cruel God of programming. Pip is faster, but version resolution is iffy.

Hell, even just assigning versions to python packages is nothing short of ridiculous. Do you use version.txt in the root folder and set it manually? Do you have it set from SCM? Which of the half a dozen packages do you use to have it set from SCM? setuptools_scm? Versioneer?

There are a set of tools in the python ecosystem that have basically no equal in any other language and these tools and the surrounding mindshare make python irreplaceable in the near term. The language itself is easy to learn and powerful enough to be able to do data analysis with ease. Good python code is easy on the eyes, which I personally consider an important aspect.

Outside of these tools, core parts of the ecosystem are basically an XKCD joke.

I tried switching to Julia as I find both the language and the ecosystem are vastly superior in their foundations. Unfortunately the maturity is not there yet, and neither is the mindshare. If I had to bet my career on adopting the language in a business setting, I'd not be prepared to do so. Which is a shame, because the situation turns into a Catch-22.

Re: Pyre: A performant type-checker for Python 3

#33

Post by short_sells_poo »

fouronnes3 wrote: post #22
dunefox wrote: post #10

As with package managers, there seem to be half a dozen different, competing type checkers for Python now...

Python type checking has entered a serious xkcd 927 phase that will get worse before it gets better.

I'd posit you are being optimistic there. Just look at the python packaging story. It had 20 years to get better and it's still only getting worse.

Re: Pyre: A performant type-checker for Python 3

#34

Post by Groxx »

staticassertion wrote: post #15
throwaway894345 wrote: post #8

Earlier quoted context omitted.

Last I checked, mypy struggled to represent recursive types. Think `JSON = Union[None, bool, str, float, int, List['JSON'], Dict[str, 'JSON']`. That's a bummer because recursive data types are darn handy. Worse, importing third party packages often fails silently and when you can get error messages they tend to be completely inactionable (I recall one error message which linked to a web page that had lots of details…

I have yet to successfully build a project with the strict mypy settings, without resorting to either turning some off or having to use an explicit Any. And a lot of the non-default settings are absolutely critical if you care about correctness. Lack of recursive types has been a major deal breaker for me. If you have a class Foo that can construct a class Bar, and a class Bar that can construct a class Foo, you can'…

This pretty much mirrors my mypy experience too. The only project I've ever successfully used it on was a single-file CLI tool that only used the stdlib.

And by "successfully" I mean "it ran at all". Every other thing I've thrown at it has caused it to crash. I quite like the concept, but implementation has been rather abysmal as far as I've seen. Has it improved in ~ the past year?

Re: Pyre: A performant type-checker for Python 3

#35

Post by globular-toast »

Anyone considering using type hints should listen to this talk: https://www.infoq.com/presentations/dynamic-static-typing/

I personally think it's mostly a waste of time to do type hinting for the purpose of catching errors in a strongly typed language like Python. Type errors just aren't practically a problem in dynamic languages. Doing types for performance is a great reason to do it, though.

Re: Pyre: A performant type-checker for Python 3

#36

Post by vorticalbox »

nerdponx wrote: post #23
jmugan wrote: post #20

PyCharm works well for me. Probably not as fancy as all this other stuff, but the type hints make the code easier to understand, and they help PyCharm help me by enabling it to find more errors and by enabling enhanced autocompletion.

PyCharm having type checking built in is excellent, but it is definitely the lowest quality out of the major 3 (Mypy, Pyright, Pyre) with respect to correctness.

I've always found its type checking to be perfectly fine, but hearing its not the best I might look into the others.

Re: Pyre: A performant type-checker for Python 3

#37

Post by codethief »

throwaway894345 wrote: post #19
codethief wrote: post #12

Earlier quoted context omitted.

> Similarly where a language with first-class support for types might have `type Foo `, Python makes you write `T = TypeVar("T"); class Foo(Generic[T])` or something like that, and it gets more confusing when you only want one of the methods to be generic and I can never remember whether that `T` takes on a single type across all uses or which scope I need to define it in, etc. I don't know about you but I find PEP 4…

Fair enough. Maybe I didn't come across that at the time or perhaps it's been since revised. Even still, it's a poor substitution for the more familiar / intuitive `class Foo[T]:` / `def foo[T](...)` style.

Hmm it might take some getting used to but I've actually found it quite straight-forward to comprehend and reason about.

The nice thing is that, since TypeVars are ordinary variables, you can re-use them / import them in multiple modules and avoid a lot of boilerplate code.

Re: Pyre: A performant type-checker for Python 3

#39

Post by alexgrover »

short_sells_poo wrote: post #32
dunefox wrote: post #10

As with package managers, there seem to be half a dozen different, competing type checkers for Python now...

It's starting to look like the huge embarrassment that is python packaging and environment management. I work with the language every day, and I still have no idea what am I supposed to use between conda, pip, setuptools/setup.py, pyproject, meta.yml, poetry, pipenv, etc... Conda is so slow that I sometimes wonder if we are being trolled by some cruel God of programming. Pip is faster, but version resolution is iffy.…

Starting to? The Python ecosystem has been pretty behind other languages for more like 10 years now. I'm still forced to use it for work but it's becoming more and more likely that "no python" will be a hard requirement for my next job search...

What tools do you find irreplaceable?

Re: Pyre: A performant type-checker for Python 3

#40

Post by Demiurge »

short_sells_poo wrote: post #32
dunefox wrote: post #10

As with package managers, there seem to be half a dozen different, competing type checkers for Python now...

It's starting to look like the huge embarrassment that is python packaging and environment management. I work with the language every day, and I still have no idea what am I supposed to use between conda, pip, setuptools/setup.py, pyproject, meta.yml, poetry, pipenv, etc... Conda is so slow that I sometimes wonder if we are being trolled by some cruel God of programming. Pip is faster, but version resolution is iffy.…

There are actually clear answers to all your questions.

All the tools you listed do different things, except maybe poetry and pipenv, so you can pick whichever one you like, you're not supposed to do anything. You can have choice, illusion of free will, etc...

As to module version, there is a standard on how to define it in __version__: https://www.python.org/dev/peps/pep-0008/#module-level-dunde...

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