# `option_either_or`
[](https://crates.io/crates/option_either_or/)
[](https://docs.rs/option_either_or)
Convert `Option<T>` into `Either<L, T>`.
## Overview
This crate introduces `either_or` and `either_or_else` to `Option` in order to facilitate
conversions from `Option` to `Either`.
It is mainly useful as generalizations of `unwrap_or`/`unwrap_or_else` where the provided default
value is of a different type than the `Some` variant, but both types implement some common trait.
## Examples
You can take advantage of `Either` implementing `Display` to provide a default value to
`Option<String>` without allocating another string...
```rust
use option_either_or::OptionEitherOr as _;
let x = Some(String::from("string"));
let y = x.either_or("default");
println!("{y}");
```
... or provide defaults to `impl Display` (or any other trait generically implemented by `Either`)
in a generic context...
```rust
fn transform(x: Option<impl Display>) -> impl Display {
use option_either_or::OptionEitherOr as _;
x.either_or_else(|| "default")
}
```
... or even provide defaults to a generic `Future`, like so:
```rust
use std::{future::Pending, time::Duration};
use option_either_or::OptionEitherOr;
async fn await_or_sleep(f: Option<impl Future<Output = ()>>) {
f.either_or_else(|| async move {
println!("doing nothing by default and sleeping...");
tokio::time::sleep(Duration::from_secs(1)).await;
println!("...slept");
})
.await
}
#[tokio::main]
async fn main() {
await_or_sleep(Some(async move {
for _ in 0..4 {
println!("something real");
tokio::time::sleep(Duration::from_millis(100)).await;
}
}))
.await;
println!("---");
await_or_sleep(Option::<Pending<()>>::None).await;
}
```