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by doboyy 2356 days ago
I really don't like the monomorphization approach to generics (I think that's the concept?), where the function/struct essentially gets duplicated for each type. It seems to mess with linkage, increase binary sizes, and increase compile times.

Other than that, Rust does seem to be an improvement and less... stressful to program in.

1 comments

You can always role dynamics dispatch yourself
Dynamic dispatch is in the language too.

    use core::fmt::Display;
    
    fn show_monomorphic<T: Display>(first: T, second: T) {
        println!("{} then {}", first, second);
    }
    
    fn show_polymorphic(first: &dyn Display, second: &dyn Display) {
        println!("{} then {}", first, second);
    }
    
    pub fn main() {
        show_monomorphic(17, 23);
        show_monomorphic("fnord", "slack");
    
        show_polymorphic(&42, &"quirkafleeg"); // mixed types!
    }
There are things you can do with each that you can't do with the other, but they are often both viable choices.
If you're doing dynamic dispatch then there is still code that's living for each specialization. Sort of solves linking because symbols don't have to be generated and compile times because you hand write the code.

To be fair, I'm only considering basic data structures and algorithms where you can get away with something like foo(void *ptr, size_t size). Maybe generics is too broad a term for that.