cell_utils

This Rust crate contains two utilities for working with std::cell::Cell: array_of_cells and project!.

The array_of_cells function converts between &Cell<[T; N]> and &[Cell<T>; N]. This is very similar to Cell::as_slice_of_cells, and I've proposed adding it to the standard library.

use cell_utils::array_of_cells;

let cell: Cell<[i32; 3]> = Cell::new([1, 2, 3]);
let array: &[Cell<i32>; 3] = array_of_cells(&cell);
array[0].set(99);
assert_eq!(cell.into_inner(), [99, 2, 3]);

The project! macro lets you access the fields of a struct or the elements of a tuple, given a reference to a containing cell.

use cell_utils::project;

struct Foo {
    bar: Bar,
}

struct Bar {
    baz: i32,
}

let mut foo = Foo { bar: Bar { baz: 42 } };
let foo_cell: &Cell<Foo> = Cell::from_mut(&mut foo);
let baz_cell: &Cell<i32> = project!(foo_cell.bar.baz);
baz_cell.set(99);
assert_eq!(foo.bar.baz, 99);

The project! macro was inspired by the cell-project crate.