# field_access

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A library for dynamic access to struct fields with `#![no_std]` support.

Field access is enabled by the `FieldAccess` trait which can be implemented
using a derive macro by the same name.


```rust
use field_access::FieldAccess;

#[derive(FieldAccess)]
struct Foo {
    a: u8
}

let mut foo = Foo { a: 1 };

// Immutable field access.
if let Some(field) = foo.field("a") {
    assert_eq!(field.as_u8(), Some(1));
}

// Mutable field access.
if let Some(mut field) = foo.field_mut("a") {
    assert_eq!(field.replace(42u8), Some(1));
}

assert_eq!(foo.a, 42);
```

## Cargo features

- `alloc`: Provide methods to interact with types from the Rust core allocation
  and collections library including `String` and `Vec<T>`. This feature pulls
  in the `alloc` library as a dependency and is enabled by default.
- `derive`: Provide a derive macro for the `FieldAccess` trait. This feature is
  enabled by default.

## License

The source code of field_access is licensed under either of
[Apache License, Version 2.0](https://github.com/martinohmann/field_access/blob/main/LICENSE-APACHE) or
[MIT license](https://github.com/martinohmann/field_access/blob/main/LICENSE-MIT) at
your option.