Crate field_path 

Field Path

Field Path provides a lightweight and type-safe abstraction for referencing and accessing nested fields within structs.

The crate is designed to make it easier to generically inspect or mutate fields without relying on heavy reflection systems or unsafe code. It does this through a combination of field identifiers and accessors that preserve type information.

Core Concepts

• Field: Represents a unique, type-safe identifier for a field path within a struct.
• Accessor: A generic wrapper providing read and write access to a field.
• FieldAccessor: A container pairing a Field with its Accessor, ensuring both always refer to the same field path.

Together, these components allow building flexible systems that can access or manipulate struct data without tightly coupling to specific types.

Example

use field_path::field_accessor;
use field_path::field_accessor::FieldAccessor;

#[derive(Default)]
struct Vec2<T> {
    pub x: T,
    pub y: T,
}

const FIELD_ACC: FieldAccessor<Vec2<f32>, f32> = field_accessor!(<Vec2<f32>>::x);

assert_eq!(FIELD_ACC.field.field_path(), "::x");

let mut v = Vec2::default();
*FIELD_ACC.accessor.get_mut(&mut v) = 42.0;
assert_eq!(FIELD_ACC.accessor.get_ref(&v), &42.0);

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License

field_path is dual-licensed under either:

• MIT License (LICENSE-MIT or http://opensource.org/licenses/MIT)
• Apache License, Version 2.0 (LICENSE-APACHE or http://www.apache.org/licenses/LICENSE-2.0)

This means you can select the license you prefer! This dual-licensing approach is the de-facto standard in the Rust ecosystem and there are very good reasons to include both.

Modules

accessor

Accessors for mapping source structures to target fields.

field

Provides abstractions for working with typed fields in a type-erased, yet type-safe manner.

field_accessor

This module defines the FieldAccessor type, which pairs a Field (representing the static path name) with an Accessor (providing functional pointers for data access).

Macros

accessor

Creates an Accessor that ensures the fields being accessed are correct for both immutable and mutable reference.

field

Creates a Field with path and type safety.

field_accessor

Creates a FieldAccessor that ensures both Field and Accessor are pointing to the same field path.

stringify_field

Stringify a field path into its canonical string form.