# Default Array-of-Option\<T\> Macros
Macros to make your life easier when dealing with default-initialized
arrays of `Option<T>` or `Cell<Option<T>>` for non-`Copy` types of `T` to `[None, ..]`.
### You may need it if ...
- You need an array of `[Option<T>; N]` initialized to `[None; N]`, or
- You need an array of `[Cell<Option<T>>; N]` initialized to `[Cell::new(None); N]`, or
- You need an array of `[RefCell<Option<T>>; N]` initialized to `[RefCell::new(None); N]`.
### You will not need it if ...
- Your types already implement `Copy` or `Clone` and you don't need cells.
- You require `#![forbid(unsafe_code)]`.
## Examples
```rust
use std::cell::Cell;
use arraysetcell::ArraySetCell;
// This type does not implement Copy.
struct Complicated;
fn it_works() {
// This doesn't compile:
let arr: [Option<Complicated>; 10] = [None; 10];
// This does:
let arr = none_arr![Complicated; 10];
// [None, None, None, ...]
assert_eq!(arr.len(), 10);
for item in arr.into_iter() {
assert!(item.is_none());
}
// The created type is an array.
let arr: [Option<Complicated>; 10] = arr;
assert_eq!(arr.len(), 10);
}
```
Likewise, arrays of `Cell<Option<T>>` can be created.
```rust
fn cell_works() {
let arr: [Cell<Option<Complicated>>; 10] = none_cell_arr![Complicated; 10];
let arr: [RefCell<Option<Complicated>>; 10] = none_refcell_arr![Complicated; 10];
}
```
## I cannot have unsafe code
If you cannot have `unsafe` code in your project, something like the following can be used:
```rust
fn not_fun() {
let arr: [Option<Complicated>; 10] = (0..10)
.into_iter()
.map(|_| None)
.collect::<Vec<_>>()
.try_into()
.map_err(|_| "try_into failed") // Debug required otherwise
.expect("initialization failed");
}
```