Crate int_to_c_enum

This crate provides a derive macro named TryFromInt. This macro can be used to automatically implement TryFrom trait for C-like enums.

Currently, this macro only supports enums with explicit discriminants.

Below is a simple example. We derive macro TryFromInt for an enum Color.

use int_to_c_enum::TryFromInt;
#[repr(u8)]
#[derive(TryFromInt, Eq, PartialEq)]
pub enum Color {
    Red = 1,
    Yellow = 2,
    Blue = 3,
}
// Then, we can use method `try_from` for `Color`.
let color = Color::try_from(1).unwrap();
assert!(color == Color::Red);

The TryFromInt macro will automatically implement trait TryFrom<u8> for Color. After macro expansion, the generated code looks like as follows:

impl TryFrom<u8> for Color {
    type Error = TryFromIntError;
    fn try_from(value: u8) -> Result<Self, Self::Error> {
        match value {
            1 => Ok(Color::Red),
            2 => Ok(Color::Yellow),
            3 => Ok(Color::Blue),
            _ => Err(TryFromIntError::InvalidValue),
        }
    }
}

Enums

• TryFromIntError
  Error type for TryFromInt derive macro

Derive Macros

• TryFromInt