[fizzybeetle]

> anyone writing Python (sans mypy) doesn't get to chastise Go for lacking generics! :)

Why do you say this point in particular? Python's duck typing makes generics very easy, no? i.e., you can write an algorithm in python that just assumes a particular method is callable and you don't have to code gen individual implementations for different types. plus the dunder (e.g., `__iadd__`) methods give a lot of useful basic functionality

[weberc2]

Mostly I was just amusing myself, but here's what I meant:

Usually when people refer to generics they're referring to a static type system that allows for expressing generic algorithms. (Untyped) Python inherently has no static type system, so necessarily can't support generics by that definition. The other definition of generics that _is_ satisfiable by (untyped) Python--the definition you presumably had in mind--is equally satisfiable by Go via its `interface{}` type. So regardless of which definition you adhere to, "Go lacks generics" is no more valid a criticism for Go than for Python.

Practically speaking, there's some syntax ceremony involved in using `interface{}` in Go; coming from Python or another dynamic language, this ceremony will probably offend your sensibilities--why is it so hard to opt out of the type system!? But that's by design--Go generally tries to keep you on the path of correctness without being overbearing (as many find stricter languages--e.g., Haskell--to be).

[coldtea]

>The other definition of generics that _is_ satisfiable by (untyped) Python--the definition you presumably had in mind--is equally satisfiable by Go via its `interface{}` type. So regardless of which definition you adhere to, "Go lacks generics" is no more valid a criticism for Go than for Python.

Well, that's not exactly the case. Interface{} might have the same tradeoffs with Python's dynamic types (plus more ceremony), but that's not the real issue.

Python is inherently a dynamic typed language, so not having types and generics is expected and idiomatic.

For Go, you have a type system and static type checking, but you can't properly use it when you resort to interface{} to make generic algorithms.

So while for Python not having types/generics is business as usual (and that's part of the very promise of the language), for Go not having generics means losing two of it's main promises, static type checking and speed.

[weberc2]

For whatever it's worth, I'm a proponent of generics in Go.

"Static type checking" does not mean "every conceivable program is safely expressable by the type system". Haskell doesn't make this promise and neither does Go.

Anyway, Go is as slow and as unsafe as Python in the ~1-5% of code that is generic. It's still a pretty good deal even if you were mistakenly expecting 0%.

[coldtea]

>"Static type checking" does not mean "every conceivable program is safely expressable by the type system". Haskell doesn't make this promise and neither does Go.

No, and I didn't make this claim or demand this either.

But it should mean: "any algorithm variation where just the type changes should be expressable by the type system without me having to rewrite e.g. a sort list for int64 lists, int32 lists, float lists, etc, it's 2019 already".

[weberc2]

That's not what static typing means. If you want it to mean that, go right ahead. I agree that Go should support that feature, but it has no bearing on the definition of static typing nor on Go's position relative to Python with respect to speed or safety.