Kagami Sascha Rosylight
2e55118ec5
Differential Revision: https://phabricator.services.mozilla.com/D264092
63 lines
2.1 KiB
Markdown
63 lines
2.1 KiB
Markdown
# array-init
|
|
|
|
[](https://crates.io/crates/array-init)
|
|
[](https://docs.rs/array-init)
|
|
|
|
The `array-init` crate allows you to initialize arrays
|
|
with an initializer closure that will be called
|
|
once for each element until the array is filled.
|
|
|
|
This way you do not need to default-fill an array
|
|
before running initializers. Rust currently only
|
|
lets you either specify all initializers at once,
|
|
individually (`[a(), b(), c(), ...]`), or specify
|
|
one initializer for a `Copy` type (`[a(); N]`),
|
|
which will be called once with the result copied over.
|
|
|
|
Care is taken not to leak memory shall the initialization
|
|
fail.
|
|
|
|
## Examples:
|
|
|
|
```rust
|
|
// Initialize an array of length 50 containing
|
|
// successive squares
|
|
|
|
let arr: [usize; 50] = array_init::array_init(|i| i * i);
|
|
|
|
// Initialize an array from an iterator
|
|
// producing an array of [1,2,3,4] repeated
|
|
|
|
let four = [1,2,3,4];
|
|
let mut iter = four.iter().copied().cycle();
|
|
let arr: [u32; 50] = array_init::from_iter(iter).unwrap();
|
|
|
|
// Closures can also mutate state. We guarantee that they will be called
|
|
// in order from lower to higher indices.
|
|
|
|
let mut last = 1u64;
|
|
let mut secondlast = 0;
|
|
let fibonacci: [u64; 50] = array_init::array_init(|_| {
|
|
let this = last + secondlast;
|
|
secondlast = last;
|
|
last = this;
|
|
this
|
|
});
|
|
```
|
|
|
|
## Minimum Supported Rust Version (MSRV)
|
|
|
|
`array-init` will only increase the MSRV on a new major
|
|
or minor release, but not for patch releases.
|
|
Any changes of the MSRV will be announced in the changelog.
|
|
When increasing the MSRV, the new Rust version must have been
|
|
released at least six months ago. The current MSRV is 1.51.0.
|
|
MSRV changes can be expected to happen conservatively.
|
|
|
|
## Licensing
|
|
|
|
Licensed under either of Apache License, Version 2.0 or MIT license at your option.
|
|
|
|
Unless you explicitly state otherwise, any contribution intentionally submitted for inclusion in this crate by you, as defined in the Apache-2.0 license, shall be dual licensed as above, without any additional terms or conditions.
|
|
|