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Honestly, I think both Python and Ruby have a subpar gradual typing story. The problem is that Python type hints are not enforced at runtime. They can can not

Honestly, I think both Python and Ruby have a subpar gradual typing story. The problem is that Python type hints are not enforced at runtime. They can can not be trusted. You have to rely on external type checkers that are relatively slow and different checker might give you different results. Probably the only mainstream backend-language getting gradual typing right is PHP. Yes, good old PHP. Dead simple type system, no productivity-sucking compile step like in Typescript, actual runtime enforcement of types contrary to Python and great static linting. Though PHP is also a fair bit less expressive and dynamic compared to both Python and Ruby so it can get away with an much simpler type system. Then again, as someone who has to work with many legacy systems, sometimes I am very grateful for the lower expressiveness.

atomicnumber3 3y ago
Y'know it's weird but it's never bothered me too much that python type hints don't do anything at runtime. It's enough to just know what someone, at some point, intended. (And PyCharm is pretty good about pointing out when they're wrong, anyway). I guess when it comes down to it, given we're not statically typing, I still get an awful lot of mileage out of just knowing when my assumptions about the code conflict with someone else's assumptions about the code (even if that other person is subtly wrong, like anystr vs str or something). Sorbet has a runtime time-checking mode I think, too, so that's actually a point in favor to ruby for you (though again with the drawbacks I mentioned of being a gem and imo being a little clunky syntax-wise).
Spivak 3y ago
> Ruby have a subpar gradual typing story Whether you agree with it or not Ruby's (the language not the developers) resistance to static typing is just how Ruby wants to be written. There are no types, only messages. The whole culture surrounding Ruby is burying all the underlying data in favor of pure message-passing nirvana. I have no ducks but I must quack.
- djur 3y ago
  This is partially true, but a pretty large chunk of idiomatic Ruby is focused on Enumerable method chaining, transforming arrays and hashes, slicing and dicing strings, etc. A language that was totally dedicated to message-passing nirvana wouldn't have regexes as a built-in data type with a literal syntax (or dictionaries, ranges, and so on)
  - chris12321 3y ago
    Those things are all just Objects in Ruby, just with some syntactic sugar, not built in data types. `/a?/` is just syntactic sugar for `Regexp.new('a?')`, ['a','b','c'] is just `Array.[]( 'a', 'b', 'c')` everything is an object being sent messages.
- gabrieledarrigo 3y ago
  > There are no types, only messages. Yes but...what is the shape of those messages? I ways prefer to know the type of the material I'm working with...
opnitro 3y ago
Enforcing the type hints at runtime gets really expensive if you allow for complex/higher order types. Typed Racket has had trouble with this since it tries to actually be a sound gradual typing system. Interesting work here: https://dl.acm.org/doi/pdf/10.1145/3434334 https://dl.acm.org/doi/pdf/10.1145/3434334 on speeding it up via static analysis (figuring out what dynamic enforcement points you can statically eliminate).

atomicnumber3 3y ago

Y'know it's weird but it's never bothered me too much that python type hints don't do anything at runtime. It's enough to just know what someone, at some point, intended. (And PyCharm is pretty good about pointing out when they're wrong, anyway). I guess when it comes down to it, given we're not statically typing, I still get an awful lot of mileage out of just knowing when my assumptions about the code conflict with someone else's assumptions about the code (even if that other person is subtly wrong, like anystr vs str or something). Sorbet has a runtime time-checking mode I think, too, so that's actually a point in favor to ruby for you (though again with the drawbacks I mentioned of being a gem and imo being a little clunky syntax-wise).

Spivak 3y ago

> Ruby have a subpar gradual typing story Whether you agree with it or not Ruby's (the language not the developers) resistance to static typing is just how Ruby wants to be written. There are no types, only messages. The whole culture surrounding Ruby is burying all the underlying data in favor of pure message-passing nirvana. I have no ducks but I must quack.

djur 3y ago
This is partially true, but a pretty large chunk of idiomatic Ruby is focused on Enumerable method chaining, transforming arrays and hashes, slicing and dicing strings, etc. A language that was totally dedicated to message-passing nirvana wouldn't have regexes as a built-in data type with a literal syntax (or dictionaries, ranges, and so on)
- chris12321 3y ago
  Those things are all just Objects in Ruby, just with some syntactic sugar, not built in data types. `/a?/` is just syntactic sugar for `Regexp.new('a?')`, ['a','b','c'] is just `Array.[]( 'a', 'b', 'c')` everything is an object being sent messages.
gabrieledarrigo 3y ago
> There are no types, only messages. Yes but...what is the shape of those messages? I ways prefer to know the type of the material I'm working with...

opnitro 3y ago

Enforcing the type hints at runtime gets really expensive if you allow for complex/higher order types. Typed Racket has had trouble with this since it tries to actually be a sound gradual typing system. Interesting work here: https://dl.acm.org/doi/pdf/10.1145/3434334 https://dl.acm.org/doi/pdf/10.1145/3434334 on speeding it up via static analysis (figuring out what dynamic enforcement points you can statically eliminate).