| lib.rs |
Procedural macros to derive numeric traits in Rust.
## Usage
Add this to your `Cargo.toml`:
```toml
[dependencies]
num-traits = "0.2"
num-derive = "0.3"
```
Then you can derive traits on your own types:
```rust
#[macro_use]
extern crate num_derive;
#[derive(FromPrimitive, ToPrimitive)]
enum Color {
Red,
Blue,
Green,
}
# fn main() {}
```
## Explicit import
By default the `num_derive` procedural macros assume that the
`num_traits` crate is a direct dependency. If `num_traits` is instead
a transitive dependency, the `num_traits` helper attribute can be
used to tell `num_derive` to use a specific identifier for its imports.
```rust
#[macro_use]
extern crate num_derive;
// Lets pretend this is a transitive dependency from another crate
// reexported as `some_other_ident`.
extern crate num_traits as some_other_ident;
#[derive(FromPrimitive, ToPrimitive)]
#[num_traits = "some_other_ident"]
enum Color {
Red,
Blue,
Green,
}
# fn main() {}
``` |
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