deref-rs

A simple Rust autodereference implementation that provides macros and derive macros to easily implement the Deref and DerefMut traits for your custom types.

Features

• Macro-based implementation: Simple procedural macros for quick Deref and DerefMut implementation
• Derive macro support: Attribute-based derive macros for more ergonomic usage
• Generic type support: Works with both regular types and generic types
• Field access: Supports both named fields and tuple-style field access
• Automatic Deref implementation: When using deref_mut! or DerefMut, Deref is automatically implemented

Installation

Add this to your Cargo.toml:

[dependencies]
deref = "0.1.0"

Usage

Using Procedural Macros

Basic Usage

use deref::{deref, deref_mut};

struct MyType {
    field: TargetType,
}

struct TargetType;

// Implement Deref for MyType
deref!(MyType, TargetType, field);

// Implement both Deref and DerefMut for MyType
// Note: This automatically implements Deref as well
deref_mut!(MyType, TargetType, field);

With Generic Types

use deref::{deref, deref_mut};
struct SrVec<T> {
    vec: Vec<T>,
}

// Implement Deref for a generic type
deref!(<T>, SrVec<T>, Vec<T>, vec);

// Implement both Deref and DerefMut for a generic type
// Note: This automatically implements Deref as well
deref_mut!(<T>, SrVec<T>, Vec<T>, vec);

Using Derive Macros

Basic Usage

use deref::{Deref, DerefMut};
#[derive(Deref)]
struct Hello<T> {
    #[auto_ref]
    inner: T,
}

#[derive(DerefMut)]
struct HelloMut<T> {
    #[auto_ref]
    inner: T,
}
// Note: DerefMut automatically implements Deref as well

With Named Fields

use deref::Deref;
#[derive(Deref)]
struct Wrapper {
    #[auto_ref]
    data: String,
}

fn main() {
    let wrapper = Wrapper {
        data: "Hello, World!".to_string(),
    };
    
    // Can access String methods directly through wrapper
    println!("Length: {}", wrapper.len());
}

With Tuple Structs

use deref_rs::Deref;

#[derive(Deref)]
struct TupleWrapper(String);

#[derive(Deref)]
struct GenericTupleWrapper<T>(#[auto_ref] T);

fn main() {
    let wrapper = TupleWrapper("Hello, Tuple!".to_string());
    
    // Can access String methods directly through wrapper
    println!("Length: {}", wrapper.len());
}

Examples

Smart Pointer Implementation

use deref_rs::Deref;
use std::ops::Deref as DerefTrait;

#[derive(Deref)]
struct MyBox<T> {
    #[auto_ref]
    value: T,
}

impl<T> MyBox<T> {
    fn new(value: T) -> Self {
        MyBox { value }
    }
}

fn main() {
    let my_box = MyBox::new(42);
    
    // Can access the inner value directly
    println!("Value: {}", *my_box);
    
    // Can call methods on the inner type
    let string_box = MyBox::new("Hello".to_string());
    println!("Length: {}", string_box.len());
}

Nested Dereferencing

use deref::{Deref, DerefMut, deref_mut};
#[derive(Debug, DerefMut)]
struct Inner<T> {
    #[auto_ref]
    value: T,
}
// Note: DerefMut automatically implements Deref for Inner<T>

#[derive(Debug)]
struct Outer<T> {
    inner: Inner<T>,
}

// Implement DerefMut for Outer using the macro
// Note: This automatically implements Deref as well
deref_mut!(<T>, Outer<T>, T, inner);

fn main() {
    let mut outer = Outer {
        inner: Inner {
            value: "Hello, World".to_string(),
        },
    };

    println!("{:?}", outer);

    // Can modify the inner value directly
    *outer += "!";
    
    println!("{:?}", outer);
}

API Reference

Macros

deref! Macro

Implements the Deref trait for a struct.

deref!(TYPE, TARGET_TYPE, FIELD)
deref!(GENERIC_PARAMS; TYPE, TARGET_TYPE, FIELD)

deref_mut! Macro

Implements both Deref and DerefMut traits for a struct.

deref_mut!(TYPE, TARGET_TYPE, FIELD)
deref_mut!(GENERIC_PARAMS, TYPE, TARGET_TYPE, FIELD)

Note: The deref_mut! macro automatically implements both Deref and DerefMut traits. You don't need to separately use deref! when using deref_mut!.

Derive Macros

Deref Derive Macro

Implements the Deref trait using the #[auto_ref] attribute to mark the target field.

DerefMut Derive Macro

Implements both Deref and DerefMut traits using the #[auto_ref] attribute to mark the target field.

Note: The DerefMut derive macro automatically implements both Deref and DerefMut traits. You don't need to separately derive Deref when deriving DerefMut.

License

This project is licensed under the MIT License - see the LICENSE file for details.

Contributing

Contributions are welcome! Please feel free to submit a Pull Request.

Changelog

0.1.0

• Initial release
• Basic deref! and deref_mut! macros
• Deref and DerefMut derive macros
• Support for generic types
• Automatic Deref implementation when using DerefMut