https://github.com/teddriggs/from_variants

A rust proc-macro to generate conversions for an enum of newtype variants
https://github.com/teddriggs/from_variants

Last synced: 2 months ago
JSON representation

A rust proc-macro to generate conversions for an enum of newtype variants

• Host: GitHub
• URL: https://github.com/teddriggs/from_variants
• Owner: TedDriggs
• Created: 2017-04-18T21:42:34.000Z (over 7 years ago)
• Default Branch: master
• Last Pushed: 2023-02-08T15:42:05.000Z (almost 2 years ago)
• Last Synced: 2024-10-16T12:05:35.906Z (3 months ago)
• Language: Rust
• Size: 64.5 KB
• Stars: 28
• Watchers: 2
• Forks: 1
• Open Issues: 1
• Metadata Files:
  • Readme: README.md
  • Changelog: CHANGELOG.md

Awesome Lists containing this project

README

        
[![Build Status](https://github.com/TedDriggs/from_variants/workflows/CI/badge.svg)](https://github.com/TedDriggs/from_variants/actions)

[![Latest Version](https://img.shields.io/crates/v/from_variants.svg)](https://crates.io/crates/from_variants)

# Newtype Variant Conversions

Rust macro crate to automatically generate conversions from variant types into the target enum.

This crate requires Rust 1.45 or above to compile on stable.

## Examples

```rust

use from_variants::FromVariants;

#[derive(Debug, Clone, PartialEq, Eq, FromVariants)]

pub enum Lorem {

    Str(String),

    Num(u16),

}

fn main() {

    assert_eq!(Lorem::Num(10), Lorem::from(10));

}

```

You can skip variants to avoid type collisions:

```rust

use from_variants::FromVariants;

#[derive(Debug, Clone, PartialEq, Eq, FromVariants)]

pub enum Ipsum {

    Hello(String),

    #[from_variants(skip)]

    Goodbye(String),

}

fn main() {

    assert_eq!(Ipsum::Hello("John".to_string()), Ipsum::from("John".to_string()));

}

```

## Features

- **Variant opt-out**: To skip a variant, add `#[from_variants(skip)]` to that variant.

- **Conversion opt-in**: Use `#[from_variants(into)]` on an enum or variant to generate conversions

  that will automatically convert - for example, accepting a `&str` for a `String` variant.

  This must be used sparingly to avoid generating conflicting impls.

- **no_std support**: Generated conversions do not depend on the standard library.