This crate exports a macro enum_from_primitive!
that wraps an
enum
declaration and automatically adds an implementation of
num::FromPrimitive
(reexported here), to allow conversion from
primitive integers to the enum. It therefore provides an
alternative to the built-in #[derive(FromPrimitive)]
, which
requires the unstable std::num::FromPrimitive
and is disabled in
Rust 1.0.
Documentation
https://andersk.github.io/enum_primitive-rs/enum_primitive/
Usage
Add the following to your Cargo.toml
file:
[dependencies]
enum_primitive = "*"
Import the crate using #[macro_use] extern crate enum_primitive
, and
wrap your enum
declaration inside the enum_from_primitive!
macro.
Example
#[macro_use] extern crate enum_primitive;
extern crate num;
use num::FromPrimitive;
enum_from_primitive! {
#[derive(Debug, PartialEq)]
enum FooBar {
Foo = 17,
Bar = 42,
Baz,
}
}
fn main() {
assert_eq!(FooBar::from_i32(17), Some(FooBar::Foo));
assert_eq!(FooBar::from_i32(42), Some(FooBar::Bar));
assert_eq!(FooBar::from_i32(43), Some(FooBar::Baz));
assert_eq!(FooBar::from_i32(91), None);
}