# nova
[](https://docs.rs/nova)
Create newtypes with great convenience.
All types generated by the following macros implement `Debug`, `Clone`, `Eq`, `PartialEq`, `Ord`, `PartialOrd`
and `Hash`. For `Copy` types, the newtype also implements `Copy`.
For convenience, each type is also generated with a conditional derive for serde serialisation and deserialisation. This is enabled
with the `serde` feature in *your own* crate, if desired.
## Example
In this example, we create a `PhoneNumber` newtype wrapper around a string. We use the macro to generate the type,
then implement a `new` function for creating it. The inner field of the newtype is only accessible from the same module, so this
ensures that the type can only be created by methods designed to validate and assert that the type is valid.
```rust
// Creates the PhoneNumber newtype here.
nova::string!(PhoneNumber);
impl PhoneNumber {
pub fn new(input: String) -> PhoneNumber {
// An extremely poorly implemented phone number validator.
assert_eq!(input.len(), 10);
Self(input)
}
}
fn blah() {
let n = PhoneNumber::new("1234567890".to_string());
let m = PhoneNumber::new("1234567890".to_string());
let o = PhoneNumber::new("1234567891".to_string());
assert_eq!(n, m);
assert_ne!(n, o);
assert!(n < o);
// Deref to get a &str
let _s: &str = &*n;
// into_inner to take back the String
let _s = n.into_inner();
}
```
## Features
- **std** (default): use `std` library
- **uuid**: add support for `uuid::Uuid` type
- **heapless**: use `heapless` to provide `Vec` and `String` implementations
### Usage in `no_std` environments
Usually you'll want to enable `heapless` functionality when in a `no_std` environment. When declaring the crate
in your `Cargo.toml`, do it like this:
```toml
nova = { version = "0.2", default-features = false, features = ["heapless"] }
```
## License
This project is 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.