Comment by fauigerzigerk
13 hours ago
I understand that this is true for a lot of application code. It's not true for library authors though, and every language needs libraries.
13 hours ago
I understand that this is true for a lot of application code. It's not true for library authors though, and every language needs libraries.
I’ve written a lot of libraries too.
The problem is generics only solve a very small part of the equation: compile time checks for composite types. But to use composite types in anything non-trivial in Go, you then need reflection. Which is slow. And if you then need reflection, you’re already passing interface types anyway plus you’re back to having to handle type-handling errors in the runtime.
So if you’re writing a library that’s expected to have any kind of performance, you’re back to code duplication and having a DoSomethingType() function signatures again.
Or you stick with reflection and take that performance hit PLUS the risk of compile time constraints being runtime errors; which is the a lose-lose scenario. And let’s also not forget that reflection can be just as verbose as code duplication, and harder to get right too.
Don’t get me wrong, I’m glad we have generics. But people on HN massively overstate the value of them in a AOT non-dynamic, strictly typed language like Go.
I guess you could argue that Go has other shortcomings that directly result in generics having limited value. But then you’re basically just arguing that you prefer coding in a different language paradigm, and at that point, you’re much better off using that other paradigm instead of complaining that Go isn’t JavaScript or Haskell.
Yes it is precisely Go’s shortcomings that would require typical use of generics to also require reflection most of the time. You would want Rust traits (or Haskell type classes) or C++ style type traits and then the need for reflection is much reduced. So Go has painted itself into a corner where generics feel bolted on and less useful than generics in other languages. It’s still Go’s fault and people rightfully argue that they should prefer a different language.
The Go language itself is never its strength but it has a good runtime, wonderful standard library and tooling. People never picked Go for being an amazing language, but rather for these other things.
Interesting, thanks - is the problem you’re describing solved by Rust’s macros (eg derive) or are there further issues you see even there?
Thanks for that, nicely put, interesting angle.