Crate enum_primitive[−][src]
Expand description
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.
Example
#[macro_use] extern crate enum_primitive;
extern crate num_traits;
use num_traits::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);
}
Macros
Wrap this macro around an enum
declaration to get an
automatically generated implementation of num::FromPrimitive
.
Helper macro for internal use by enum_from_primitive!
.
Helper macro for internal use by enum_from_primitive!
.
Enums
The Option
type. See the module level documentation for more.
Traits
A generic trait for converting a number to a value.