#cell #default #reference #copy #mutate #refcell

no-std cell-ref

Cell type with methods for by-reference mutation

2 releases

0.1.1 May 18, 2022
0.1.0 Apr 27, 2022

#289 in No standard library


174 lines


This crate provides a Cell type (like the standard library’s Cell) with methods for safely mutating and inspecting the inner value by reference (with and with_mut).

For Copy types, this is implemented with get and set, but through an extension trait, this crate provides those same operations for types that are Default but not Copy. A get method is also available for types that are both Default and Clone.

This crate depends only on core, so it can be used inside no_std environments.


use cell_ref::{Cell, CellExt};

let c1 = Cell::new(2_u8);
c1.with_mut(|x| *x += 3);
assert!(c1.get() == 5);

let c2 = Cell::new(vec![1, 2, 3]);
c2.with_mut(|v| v.push(4)); // Works even though `Vec` isn't `Copy`
assert_eq!(c2.with(Vec::len), 4);
let v = c2.get(); // Clones the vector

No runtime deps