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https://github.com/teenjuna/prae
prae is a crate that aims to provide a better way to define types that require validation.
https://github.com/teenjuna/prae
macros rust rust-library validation
Last synced: about 2 months ago
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prae is a crate that aims to provide a better way to define types that require validation.
- Host: GitHub
- URL: https://github.com/teenjuna/prae
- Owner: teenjuna
- License: unlicense
- Created: 2021-06-25T06:22:32.000Z (almost 3 years ago)
- Default Branch: master
- Last Pushed: 2023-01-31T14:29:18.000Z (over 1 year ago)
- Last Synced: 2024-03-24T15:04:05.053Z (2 months ago)
- Topics: macros, rust, rust-library, validation
- Language: Rust
- Homepage:
- Size: 83 KB
- Stars: 129
- Watchers: 2
- Forks: 4
- Open Issues: 6
-
Metadata Files:
- Readme: README.md
- License: LICENSE
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- my-awesome-stars - teenjuna/prae - prae is a crate that aims to provide a better way to define types that require validation. (Rust)
README
# prae
[](https://crates.io/crates/prae)
[](https://docs.rs/prae)
[](https://crates.io/crates/prae)
`prae` is a crate that aims to provide a better way to define types that
require validation.
The main concept of the library is the [`Wrapper`](crate::Wrapper) trait.
This trait describes a
[`Newtype`](https://rust-unofficial.github.io/patterns/patterns/behavioural/newtype.html)
wrapper struct that contains some inner value and provides methods to
construct, read and mutate it.
The easiest way to create a type that implements [`Wrapper`](crate::Wrapper)
is to use [`define!`](crate::define) and [`extend!`](crate::extend) macros.
## Example
Suppose you want to create a type `Username`. You want this type to be a
`String`, and you don't want it to be empty. Traditionally, you would create
a wrapper struct with getter and setter functions, like this simplified
example:
```rust
#[derive(Debug)]
pub struct Username(String);
impl Username {
pub fn new(username: &str) -> Result {
let username = username.trim().to_owned();
if username.is_empty() {
Err("value is invalid")
} else {
Ok(Self(username))
}
}
pub fn get(&self) -> &str {
&self.0
}
pub fn set(&mut self, username: &str) -> Result<(), &'static str> {
let username = username.trim().to_owned();
if username.is_empty() {
Err("value is invalid")
} else {
self.0 = username;
Ok(())
}
}
}
let username = Username::new(" my username ").unwrap();
assert_eq!(username.get(), "my username");
let err = Username::new(" ").unwrap_err();
assert_eq!(err, "value is invalid");
```
Using `prae`, you will do it like this:
```rust
use prae::Wrapper;
prae::define! {
#[derive(Debug)]
pub Username: String;
adjust |username| *username = username.trim().to_owned();
ensure |username| !username.is_empty();
}
let username = Username::new(" my username ").unwrap();
assert_eq!(username.get(), "my username");
let err = Username::new(" ").unwrap_err();
assert_eq!(err.original, "value is invalid");
assert_eq!(err.value, "");
```
Futhermore, `prae` allows you to use custom errors and extend your types.
See docs for [`define!`](crate::define) and [`extend!`](crate::define) for
more information and examples.
## Compilation speed
The macros provided by this crate are declarative, therefore make almost
zero impact on the compilation speed.
## Performarnce impact
If you find yourself in a situation where the internal adjustment and
validation of your type becomes a performance bottleneck (for example, you
perform a heavy validation and mutate your type in a hot loop) - try
`_unprocessed` variants of [`Wrapper`] methods. They won't call
[`Wrapper::PROCESS`]. However, I strongly advise you to call
[`Wrapper::verify`] after such operations.
## Feature flags
`prae` provides additional features:
Name | Description
---|---
`serde` | Adds the [`impl_serde`] plugin.
## Credits
This crate was highly inspired by the
[tightness](https://github.com/PabloMansanet/tightness) crate. It's basically
just a fork of tightness with a slightly different philosophy.
See [this](https://github.com/PabloMansanet/tightness/issues/2) issue for details.
License: Unlicense