Zhi Enum

Easily create casting traits with unknown field support.

Usage

1. Add EnumConvert or EnumTryConvert into the derive attribute.

```rust use zhi_enum::{EnumConvert, EnumTryConvert};

[derive(Debug, Ord, PartialOrd, Eq, PartialEq, EnumConvert)]

[repr(u8)]

enum NumberConvert { Zero, One, Two, Three, Four, Ten = 10, Eleven, Twenty = 10 + 10, TwentyOne, #[zhi_enum(unknown)] Unknown(u8), }

[derive(Debug, Ord, PartialOrd, Eq, PartialEq, EnumTryConvert)]

[repr(u8)]

enum NumberTryConvert { Zero, One, Two, Three, Four, Ten = 10, Eleven, Twenty = 10 + 10, TwentyOne, #[zhi_enum(unknown)] Unknown(u8), }

```

1. Then, you can use .from/.into convert functions

```rust asserteq!(NumberConvert::Three.intou8(), 3u8); asserteq!(NumberTryConvert::Three.tryintou8().unwrap(), 3u8); asserteq!(NumberConvert::Ten.intou8(), 10u8); asserteq!(NumberTryConvert::Ten.tryintou8().unwrap(), 10u8); asserteq!(NumberConvert::Eleven.intou8(), 11u8); asserteq!(NumberTryConvert::Eleven.tryintou8().unwrap(), 11u8); asserteq!(NumberConvert::TwentyOne.intou8(), 21u8); asserteq!(NumberTryConvert::TwentyOne.tryintou8().unwrap(), 21u8);

asserteq!(NumberConvert::from(3u8), NumberConvert::Three); asserteq!(NumberTryConvert::try_from(21u8).unwrap(), NumberTryConvert::TwentyOne) ```

Handle unknown discriminant

• If you have defined a variant with #[zhi_enum(unknown)] attribute in your enum like this : ```rust

  [zhi_enum(unknown)]

  Whatever(repr type), `` which therepr typeis the represented type as you define use#[repr(...)]`.

  Then, when you convert a repr type into enum type, an unknown discriminant will be converted to this variant with its unknown value.

• If you have not defined, the .try_into() will returns Err(UnknownVariantError{}), and the .into() will call panic!.

FAQ

• Error E0658

  If you get this error: error[E0658]: custom discriminant values are not allowed in enums with tuple or struct variants --> <source>:2:9 It means that your rustc version is lower than 1.56.

  You can just upgrade your rustc. Or if you don't want upgrade, you have to add #![feature(arbitrary_enum_discriminant)] to your project.

License

BSD-3-Clause