Attribute Macro bank 

#[bank]

Available on crate feature bank only.

Mark a function, static, impl block, or trait as banked.

Everything banked is Warp-colored, the same way async colors code: a -> R becomes -> impl Warp<Output = R>, captured by the call and run with .drive() (the Future / .await model). The forms:

• On a function fn f(a: A) -> R (generic or not): the body moves to the bank and f(a) returns impl Warp<Output = R>. Generics are carried onto the wrapper, so each instantiation is banked independently.
• On a static: the data moves to the bank and a Far to it is exposed.
• On an impl block: every method is rewritten the same way, the receiver becoming the first argument. Call as value.method(args).drive().
• On a trait: each method signature is colored to -> impl Warp<..> (RPITIT), exactly as an async fn in a trait desugars. A #[bank] impl of that trait then supplies the bodies.

Inside any banked body the ambient bank token is injected, and .drive (run a Warp), .invoke (a far dispatch), and .there (borrow far data) are threaded onto it automatically.

Examples

#[bank]
pub static TABLE: [u8; 4] = [1, 2, 3, 4];

#[bank]
pub fn play(note: u8) -> u8 {
    let base = TABLE.there(|t| t[0]);   // borrow banked data
    note.wrapping_add(base)
}

pub struct Point { pub x: u8, pub y: u8 }

#[bank]
impl Point {
    pub fn shift(&self, dx: u8) -> u8 { self.x.wrapping_add(dx) }
}
// call site: `p.shift(3).drive()`