let a => import 'arrays';
let s => import 'stream';

let vmath f v1 v2 =>
    s.zip (a.stream v1) (a.stream v2)
    -> s.map (@ m v =>
        let [v1 v2] => v;
        f (v1 { == s.end => 0 }) (v2 { == s.end => 0 });
    )
    -> s.collect
    ;

let smath f scalar vector => a.stream vector -> s.map (f scalar) -> s.collect;

let v+ => vmath +;
let v- => vmath -;

let s* => smath *;
let s/ => smath /;