multithreading - Future::spawn() kinda useless? How can I multi-thread this? -

excerpt main here:

let value: value = json::from_str(&sbuf).unwrap(); let coords = value.find("coordinates").unwrap().as_array().unwrap(); let x = future::spawn(|| coords.iter().fold(0f64, |mut a,b| { += read_coord_value(&b, "x"); })); let y = future::spawn(|| coords.iter().fold(0f64, |mut a,b| { += read_coord_value(&b, "y"); })); let z = future::spawn(|| coords.iter().fold(0f64, |mut a,b| { += read_coord_value(&b, "z"); }));  println!("x: {}; y: {}; z: {}",          x.await().unwrap(),          y.await().unwrap(),          z.await().unwrap()); 

so, basically, i'm doing here won't work because spawn call requires passed have static lifetime--which means there no work can avoid repeating. @ all. pointless.

what's good way threading here?

here, multithreading, need used scoped threads, std::thread::scoped(..).

these threads not need 'static closure execute, must joined.

for example:

use std::thread::scoped;  fn main() {     let coords = [(1f64,2f64,3f64),(1.,2.,3.),(1.,2.,3.),(1.,2.,3.)];     let x = scoped(|| coords.iter().fold(0f64, |mut a,b| { += b.0; }));     let y = scoped(|| coords.iter().fold(0f64, |mut a,b| { += b.1; }));     let z = scoped(|| coords.iter().fold(0f64, |mut a,b| { += b.2; }));      println!("x: {}; y: {}; z: {}",              x.join(),              y.join(),              z.join()); }