# aksr
A Rust derive macro that automatically generates **Builder Lite** pattern methods for structs, supporting both named and tuple structs with extensive customization options.
## Builder Lite Pattern
`aksr` implements the [Builder Lite](https://matklad.github.io/2022/05/29/builder-lite.html) pattern, where the struct itself acts as the builder. Unlike traditional builders that require a separate builder object, Builder Lite is an incremental, zero-cost evolution from the `new()` or `Default::default()` method.
**Requirements:**
- Struct must implement `Default` trait, OR
- Struct must have a `new()` method
This allows you to use the builder pattern without creating a separate builder type, making it especially useful for rapidly evolving application code.
## Features
- 🚀 **Builder Lite pattern** - Zero-cost, incremental builder evolution
- 🎯 **Field aliases** for more intuitive API
- 📦 **Vector extension** methods for incremental updates
- 🔧 **Flexible customization** via attributes
- 💡 **String optimization** with `&str` → `String` and `&[String]` support
- 🎁 **Smart Option handling** for `Vec<T>` with empty check
- ⚡ **Zero-cost abstractions** following Rust best practices
## Installation
Add `aksr` to your `Cargo.toml`:
```toml
[dependencies]
aksr = "0.0.5"
```
## Examples
Run the examples to see all features in action:
```bash
cargo run --example rect # Named struct
cargo run --example color # Tuple struct
```
To see the generated code:
```bash
cargo install cargo-expand # Install expand tool
cargo expand --example rect # View generated code
```
- [`examples/rect.rs`](examples/rect.rs) - Named struct with all features
- [`examples/color.rs`](examples/color.rs) - Tuple struct with all features
## Supported Attributes
| `skip` | Skip both getter and setter | `true`, `false` | `#[args(skip = false)]` |
| `alias` | Field alias for setter/getter | String | `#[args(alias = "field_name")]` |
| `setter` | Control setter generation | `true`, `false` | `#[args(setter = true)]` |
| `getter` | Control getter generation | `true`, `false` | `#[args(getter = true)]` |
| `allow` | Whitelist specific features | `setter`, `getter`, `extend`, `skip` | `#[args(allow(xxx, xxx))]` |
| `except` | Blacklist specific features | `setter`, `getter`, `extend`, `skip` | `#[args(except(xxx, xxx))]` |
| `visibility` | Control both getter/setter visibility | `"pub"`, `"private"`, `"pub(crate)"`, `"pub(self)"`, `"pub(super)"`, `"pub(in path)"` | `#[args(visibility = "pub(crate)")]` |
| `setter_visibility` | Control setter visibility (overrides `visibility` if present) | same as above | `#[args(setter_visibility = "pub")]` |
| `getter_visibility` | Control getter visibility (overrides `visibility` if present) | same as above | `#[args(getter_visibility = "pub")]` |
| `setter_prefix` | Custom setter prefix | String | `#[args(setter_prefix = "with")]` |
| `getter_prefix` | Custom getter prefix (named / tuple) | String | `#[args(getter_prefix = "field_name")]` / `#[args(getter_prefix = "nth")]` |
| `inline` | Control inline for both getter/setter | `true`, `false`, `"always"` | `#[args(inline = true)]` |
| `getter_inline` | Control getter inline attribute | `true`, `false`, `"always"` | `#[args(getter_inline = "always")]` |
| `setter_inline` | Control setter inline attribute | `true`, `false`, `"always"` | `#[args(setter_inline = true)]` |
| `extend` | Enable extend methods for Vec | `true`, `false` | `#[args(extend = false)]` |
## License
This project is licensed under [LICENSE](LICENSE).