Newtype Variant Conversions

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

This crate requires Rust 1.15 or above to compile on stable.

Examples

```rust

[macro_use]

extern crate from_variants;

[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

[macro_use]

extern crate from_variants;

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

pub enum Ipsum { Hello(String),

#[from_variants(skip)]
Goodbye(String),

}

fn main() { asserteq!(Ipsum::Hello("John".tostring()), Ipsum::from("John".to_string())); } ```

Features

• Variant opt-out: To skip a variant, add #[from_variants(skip)] to that variant.
• Conversion support: Use #[from_variants(into)] at the enum or variant level to get a generated conversion that accepts Into<VariantType>. In practice, this will only work with types defined in the same crate; otherwise you'll get conflicting impl errors.
• no_std support: Generated conversions do not depend on the standard library.