rusty-hkt

A lightweight, no_std compatible library for emulating higher-kinded types in Rust.

Overview

rusty-hkt provides traits and implementations that enable functional programming patterns requiring higher-kinded types, which are not natively supported in Rust's type system.

The library uses a trait-based approach to emulate higher-kinded types, allowing you to write generic code over type constructors such as Option, Result, Vec, and others.

Features

No standard library requirement: Works in no_std environments
Functional abstractions: Includes Functor, Applicative, and Monad traits
Built-in implementations for common Rust types:
- Option
- Result
- Vec (requires the alloc feature)
- Box (requires the alloc feature)
- Identity (a simple wrapper type)
Zero dependencies beyond the Rust core library

Usage

Add this to your Cargo.toml:

[dependencies]
rusty-hkt = "0.1.0"

Basic Example

use rusty_hkt::{Functor, OptionHKT, map};

fn main() {
    let opt = Some(3);
    let doubled = map::<OptionHKT, _, _, _>(opt, |x| x * 2);
    assert_eq!(doubled, Some(6));
}

Working with Generic Type Constructors

use rusty_hkt::{Functor, HKT};

// A function that works with any Functor
fn double_inside<F: Functor, A>(fa: F::Applied<A>) -> F::Applied<A>
where
    A: std::ops::Mul<Output = A> + Copy,
{
    F::map(fa, |x| x * x)
}

// Can be used with Option, Result, Vec, etc.

License

Licensed under the Apache License, Version 2.0. See the LICENSE file for more info.

Contributing

Contributions are welcome! Please feel free to submit a Pull Request.

Contact

GitHub: voltageddebunked
Email: rusindanilo@gmail.com

rusty-hkt 0.1.0