I'm experimenting with #Rust again, and my eyes always bleed with the "lifetime annotation syntax" - why does it have to use an apostrophe 😩 .
&'a mut i32
fn longest<'a>(x: &'a str, y: &'a str) -> &'a str {
impl<'a> System<'a> for LeftWalker {
type SystemData = (ReadStorage<'a, LeftMover>,
WriteStorage<'a, Position>);
But this time I'll try not to rage quit in digust again. I'll stick until this experiment ends. #rustlang
Another one:
- Generics in every language: Vector<MyType>()
- Rust:
Nope:
Vec<u32>::new();
This works:
Vec::<u32>::new();
And this ALSO works:
(Vec <u32)>::new();
So I can't use the universal language of: Vec<u32>::new();
But I can do (Vec <u32)>::new();
What kind of syntax is that? For the past 28yrs I used more than 12+ langs in every kind of project & the ugliest language I've seen is Rust.
Yes, EVEN UGLIER THAN ERLANG, at least Erlang is consistent and makes sense.
Vec::<u32>::new() is a general syntax used for adding generics when calling a function.
(Vec<u32>)::new() does not work because it tries to interpret stuff in () as an expression.
<Vec<u32>>::new() works because <> are like () but for types. This is often used to call a function from a specific trait when multiple options exist. example: trait A has do_thing(), trait B too, but want to call that of trait A:
```
let v = Vec::new();
// these are equivalent due to the argument allowing type inference
<Vec<u32> as A>::do_thing(&v);
A::do_thing(&v);
// this one needs the cast to know which type that implements B to call it on
<Vec<u32> as B>::do_thing();
```
playground: https://play.rust-lang.org/?version=stable&mode=debug&edition=2021&gist=0e2187a7649ab5f3caeb1ce56d63970b
Alfred R. Baudisch
TudbuT