Python’s “type hints” are a bit of a disappointment to me

Post by seti0Cha » Thu, Apr 21, 2022, 10:12 PM UTC

the_af wrote: post #53

ledauphin wrote: post #20

this article is so full of... not-very-educated thoughts on gradual typing in a dynamic language that it's hard to know where to start. A few concrete criticisms: 1. If you're using a dynamic language, then _by definition_ the language will not enforce your static hints at runtime. However, good news! Python has always been strongly typed, and _does_ enforce types at runtime! 2. A number of the examples given would b…

I can only speak about my own experience: Most people I know writing Python don't use type hints because they are too much of a hurdle for very little payoff. The tooling that pays attention to type hints is slow as molasses or difficult to use or understand. The type hints themselves are of dubious use. As a fan and advocate of static typing, I find myself advocating for type hints anyway, but I must agree I often c…

Post by zokier » Thu, Apr 21, 2022, 10:16 PM UTC

the_af wrote: post #73

xarope wrote: post #70

Earlier quoted context omitted.

as a reminder for yourself/others who need to read/maintain your code? (I am often reminded of my perl days, where something I thought idiomatic 3 days ago, is now completely incomprehensible when I just want to make a minor change)

So is it simply a standardized comment then? I will have a really bad time convincing my team mates, if that's the case. It's especially bad because, like any comment, it can say one thing but the code may do something different (actually happened to me).

Post by minusf » Thu, Apr 21, 2022, 10:18 PM UTC

gnulinux wrote: post #72

the_af wrote: post #65

Earlier quoted context omitted.

Honest question: what's the point of type hinting without type checking ? I must be mistaken, but I always thought "type hinting" was a synonym of "optional type annotations". But if you're not using those annotations for actual type checking at some point , what are they good for?

It is good for programmers. Programmers think in many different ways, but it seems to me that a sizable portion of programmers think of code in terms types. Type hinting makes it easy to convey type ideas. Where are we going from which type. I should say that anecdotally I find type hinting very useful when I'm reviewing a PR from a part of the code I'm not intensely familiar with.

Post by theodorejb » Thu, Apr 21, 2022, 10:19 PM UTC

ledauphin wrote: post #20

this article is so full of... not-very-educated thoughts on gradual typing in a dynamic language that it's hard to know where to start. A few concrete criticisms: 1. If you're using a dynamic language, then _by definition_ the language will not enforce your static hints at runtime. However, good news! Python has always been strongly typed, and _does_ enforce types at runtime! 2. A number of the examples given would b…

Post by ljojiasdf » Thu, Apr 21, 2022, 10:20 PM UTC

zmgsabst wrote: post #57

Znafon wrote: post #42

Earlier quoted context omitted.

Python typing supports duck typing: https://peps.python.org/pep-0544/ and heterogeneously typed ducts: https://peps.python.org/pep-0589/

I read 0544 and the proposal for protocols fails to support the main benefit of duck typing, as it requires the substituted-for class to be defined as a protocol. Traditionally, duck typing is used to inject types into a library that isn’t expecting extension at that particular point — eg, substituting a test class for a real class in a data object that normally wouldn’t be a protocol. I’m not seeing how that PEP add…