mirror of
https://github.com/rust-lang/rust.git
synced 2024-11-27 01:04:03 +00:00
783b56ba68
More practical examples for `Option::and_then` & `Result::and_then`
To be blatantly honest, I think the current example given for `Option::and_then` is objectively terrible. (No offence to whoever wrote them initially.)
```rust
fn sq(x: u32) -> Option<u32> { Some(x * x) }
fn nope(_: u32) -> Option<u32> { None }
assert_eq!(Some(2).and_then(sq).and_then(sq), Some(16));
assert_eq!(Some(2).and_then(sq).and_then(nope), None);
assert_eq!(Some(2).and_then(nope).and_then(sq), None);
assert_eq!(None.and_then(sq).and_then(sq), None);
```
Current example:
- does not demonstrate that `and_then` converts `Option<T>` to `Option<U>`
- is far removed from any realistic code
- generally just causes more confusion than it helps
So I replaced them with two blocks:
- the first one shows basic usage (including the type conversion)
- the second one shows an example of typical usage
Same thing with `Result::and_then`.
Hopefully this helps with clarity.
|
||
|---|---|---|
| .. | ||
| benches | ||
| primitive_docs | ||
| src | ||
| tests | ||
| Cargo.toml | ||