Static generics

Allow statics in function generics:

fn post_event<T: Event + ?Sized, static STUFF: AtomicUsize = ATOMIC_USIZE_INIT, static STUFF_INIT: Once = ONCE_INIT>(bus: &EventBus, event: &mut T) -> bool {
STUFF_INIT.call_once(|| initialization routine that uses STUFF);
let id = STUFF.load(Relaxed);
let downcasted_any = EVERYTHING[id].downcast_ref::<Handlers<T>>().expect("something");
// skipped

If the caller doesn’t specify where the statics are stored, and the default values are consts, they will be created at the call site with the specified const initializers. This allows a little code generation that’s not as powerful as macros and as such doesn’t need the ! at the end and can actually interact with the type system for once.

This allows high-performance code without adding “macro fns” like I suggested elsewhere.

" Rust is a systems programming language that runs blazingly fast, […] " -

(* unless you’re trying to write high-performance code in 100% safe rust.)

1 Like

This syntax does not look like it creates statics at the calls site,maybe you could change the syntax to be more evocative of what it’s doing.

I think it would be more obvious if the syntax was out static STUFF: AtomicUsize = ATOMIC_USIZE_INIT,and the syntax you have now was reserved for passing pre-existing statics.

hmm, fair enough. I’m not sure I like that syntax tho.

and you can still specify your own statics, for further optimization. (in the event example, if you’re posting the same event in many places)

Sooo, how would a function call be an expression if the “return value” simultaneously needs to be an item (declaration) too?

let foo = fn_call();
// becomes
let foo = {
static FOO: ... = ...;
static BAR: ... = ...;
fn_call<FOO, BAR>()


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