Macro col 

macro_rules! col {
    ($($v:expr),* $(,)?) => { ... };
    (
        @ alloc $($unsafe:ident)? ($stack:ident) ($var:pat) (uninit::<$ty:ty >, $($arg:expr),+
        $(,)?)
    ) => { ... };
    (
        @ alloc $($unsafe:ident)? ($stack:ident) ($var:pat) (zero::<$ty:ty >, $($arg:expr),+
        $(,)?)
    ) => { ... };
}

creates a col::Col containing the arguments

use faer::col;
let col_vec = col![3.0, 5.0, 7.0, 9.0];
assert_eq!(col_vec[0], 3.0);
assert_eq!(col_vec[1], 5.0);
assert_eq!(col_vec[2], 7.0);
assert_eq!(col_vec[3], 9.0);