Holda

Holda is a Rust library that provides convenience macros for creating domain objects, especially those that wrap existing types, with built-in support for serde serialization and deserialization. It simplifies the process of creating value types with common trait implementations, reducing boilerplate and improving code readability.

Features

• Automatic Trait Implementations: The StringHolda and Holda derive macros automatically implement common traits like From, AsRef, Deref, Display, Debug, PartialEq, Eq, PartialOrd, Ord, Hash, and Clone.
• serde Support: Easily enable serde serialization and deserialization for your wrapper types with the serde feature.
• Customizable: Skip specific trait implementations using the #[holda(...)] attribute.
• String-Specific Macro: The StringHolda macro is optimized for creating wrappers around String types, providing FromStr implementations.

Usage

Add holda to your Cargo.toml:

[dependencies]

holda = "0.1.0"

StringHolda Macro

The StringHolda macro is designed for structs that hold a String. It automatically implements traits and provides FromStr implementation.

use holda::StringHolda;

#[derive(StringHolda)]
struct UserName {
    inner: String,
}

fn main() {
    let name = "bruh";
    let user_name: UserName = name.parse().unwrap();
    assert_eq!(*user_name, name);
    let user_name = UserName::from(name);
    assert_eq!(*user_name, name);
}

With the serde feature enabled, you can serialize and deserialize the UserName struct:

use holda::StringHolda;
use serde::Deserialize;
use serde::Serialize;

#[derive(StringHolda, Serialize, Deserialize, Debug, PartialEq)]
struct UserName {
    inner: String,
}

fn main() {
    let data = r#"
    {
        "inner": "Bruh"
    }
    "#;
    let user_name: UserName = serde_json::from_str(data).unwrap();
    println!("{:?}", user_name);
    assert_eq!(*user_name, "Bruh");
}

Holda Macro

The Holda macro is more generic and can be used with any type. It requires specifying the field name as inner.

use holda::Holda;
use uuid::Uuid;

#[derive(Holda)]
struct MyUuidWrapper {
    inner: Uuid,
}

fn main() {
    let uuid = Uuid::new_v4();
    let wrapper = MyUuidWrapper::new(uuid);

    assert_eq!(*wrapper, uuid);
}

You can skip trait implementations using the #[holda(...)] attribute:

use holda::Holda;

#[derive(Holda)]
#[holda(NoDisplay, NoEq, NoOrd, NoHash)]
struct MyUnitWrapper {
    inner: (),
}

fn main() {
    let wrapper = MyUnitWrapper::new(());
    assert_eq!(*wrapper, ());
}

serde Feature

To enable serde support, add the serde feature to your Cargo.toml:

[dependencies]

holda = { version = "0.1.0", features = ["serde"] }

serde = { version = "1.0", features = ["derive"] } # required

serde_json = "1.0" # required for testing

Now, the generated code will include serde::Serialize and serde::Deserialize implementations for your wrapper types.

Skipping Trait Implementations

You can use the #[holda(...)] attribute to skip specific trait implementations. The following options are available:

• NoDisplay: Skips implementing Display.
• NoEq: Skips implementing PartialEq and Eq.
• NoOrd: Skips implementing PartialOrd and Ord.
• NoHash: Skips implementing Hash.
• NoClone: Skips implementing Clone.
  • NoSerde: Skips implementing Serialize and Deserialize.

License

This project is licensed under the MPL-2.0 License. See the LICENSE file for details.