fieldmap

Zero cost compile-time map based on struct.

Derive `Field`

#[derive(Field)] implements Field.

Following example implement Field<u8>, Field<u16>, Field<String> and access field by field type.

use fieldmap::Field;

#[derive(Field)]
struct ExampleType {
    value_u8: u8,
    value_u16: u16,
    value_s: String,
}

let x = ExampleType {
    value_u8: 100,
    value_u16: 200,
    value_s: "300".into(),
};

assert_eq!(*Field::<u8>::get(&x), 100);
assert_eq!(*Field::<u16>::get(&x), 200);
assert_eq!(*Field::<String>::get(&x), "300");

#[derive(Field)] can use only struct with different type of each field.

Derive `Fields`

#[derive(Fields)] implements [Fields].

You need to specify #[fields(item = "{TraitName}")].

use fieldmap::Fields;
use std::fmt::Debug;

#[derive(Fields)]
#[fields(item = "Debug")]
struct ExampleType {
    value_u8: u8,
    value_u16: u16,
    value_s: String,
}

let x = ExampleType {
    value_u8: 100,
    value_u16: 200,
    value_s: "300".into(),
};

for (name, value) in x.iter() {
    println!("{} = {:?}", name, value);
}

Output:

value_u8 = 100
value_u16 = 200
value_s = "300"

Limitation

Only 'static type can implement Fields. Because this limitation is caused by Rust not supporting GAT (generic associated types), so the limitation may be removed in the future.

License

This project is dual licensed under Apache-2.0/MIT. See the two LICENSE-* files for details.

Contribution

Unless you explicitly state otherwise, any contribution intentionally submitted for inclusion in the work by you, as defined in the Apache-2.0 license, shall be dual licensed as above, without any additional terms or conditions.

frozenlib/fieldmap