# conditional-assignment
This is a very simple, small crate to help make conditional assignments more
ergonomic.
## Minimum Supported Rust Version (MSRV)
According to [cargo-msrv](https://github.com/foresterre/cargo-msrv), the MSRV
is `1.56.1`. Given how simple this crate is, I wouldn't be surprised if the
MSRV is lower, but I didn't check. Try it!
## Why
Sometimes this:
```rust,ignore
let outcome = condition.pick(positive, negative)
```
looks better than this:
```rust,ignore
let outcome = if condition {
positive
} else {
negative
}
```
## Examples
Below are a few examples. See [tests](./tests/mod.rs) for more. These are just
examples to show the concept. If you find yourself nesting lots of `pick`s,
there is probably a better/prettier way. Chaining `pick`s seems better, but
still within reason. In some situations `map` makes more sense.
```rust
// Bring the trait into scope so you can use it.
use conditional_assignment::ConditionalAssignment;
// Return a response string depending on whether
// the bool is true or false.
fn get_response_string(correct: bool) -> String {
correct.pick(
"That's correct, well done!",
"Not quite, try again!"
).to_owned()
}
// Determine if a number is a multiple of 2, 3, and 5.
fn multiple_of_2_3_5(num: u32) -> bool {
(num % 2 == 0).pick(
(num % 3 == 0).pick(
(num % 5 == 0).pick(
true,
false
),
false
),
false,
)
}
// Get whether a &str is lowercase and get its length.
// If the &str is none, returns (None, None).
// If the &str is empty, return (None, Some(0)).
// If the &str is not empty, return (Some(<is lowercase>), Some(<length>)).
// ...
// Except not really! `a.unwrap()` can panic, because it gets evaluated before
// we know that the `Option<&str>` is `Some(&str)`
fn is_all_lower_and_len(a: Option<&str>) -> (Option<bool>, Option<usize>) {
a.pick(
{
let a = a.unwrap(); // This can panic! :(
let len_a = a.len();
(
(len_a == 0).pick(None, Some(a == a.to_lowercase())),
Some(len_a),
)
},
(None, None),
)
}
```
### License
Licensed under either of
* Apache License, Version 2.0, ([LICENSE-APACHE](./LICENSE-APACHE) or <http://www.apache.org/licenses/LICENSE-2.0>)
* MIT license ([LICENSE-MIT](./LICENSE-MIT) or <http://opensource.org/licenses/MIT>)
at your option.
#### Contribution
Unless you explicitly state otherwise, any contribution intentionally
submitted for inclusion in the work by you, as defined in the Apache-2.0
license, shall be dual licensed as above, without any additional terms or
conditions.