Idea: Wrap &[&(mut) [T]] to allow access like &(mut) [T]

[stackinspector]

It seems common to have no-continuous bytes (or other things) that need to be read or written continuously one by one, and copying them into new continuously memory requires additional allocation and copy overhead.

[nerditation]

isn't Iterator::flat_map() already does that? just a quick note, to get a &mut T, you must use &mut &mut T, not & &mut T, so your example should use &mut [&mut [T] if you want to an iterator for &mut T.

fn for_each_nested<'a, T: 'a>(seq: &mut [&mut [T]], mut f: impl FnMut(&mut T)) {
	for x in seq.iter_mut().flat_map(|slice| slice.iter_mut()) {
		f(x)
	}
}

fn main() {
	let mut a1 = [0, 1, 2];
	let mut a2 = [3, 4];
	fn inc(x: &mut isize) {
		*x += 1;
	}
	for_each_nested(&mut [&mut a1[..], &mut a2[..]], inc);
}