custom_attrs 1.2.0

//! # Custom Attrs
//! 
//! A library that allows you to configure values specific to each variants of an enum.
//! 
//! ## Features
//! - Optional attributes
//! - Default values
//!
//! ## Examples
//! 
//! ```
//! use custom_attrs::CustomAttrs;
//! 
//! // ...
//! 
//! #[derive(CustomAttrs)]
//! 
//! // set the attributes
//! #[attr(pub a: usize)]
//! #[attr(b: Option<usize>)] // attributes can be optional
//! #[attr(c: &'static str = "Hello world!")] // and can also have default values
//! enum Enum {
//!     #[attr(a = 5)]
//!     #[attr(b = 3)]
//!     Variant1,
//! 
//!     #[attr(a = 3)]
//!     #[attr(c = "Hello again !")]
//!     Variant2,
//! }
//! 
//! fn main() {
//!     let a = Enum::Variant1.get_a();
//! }
//! ```
//! 
//! See the examples directory for more details.
//! 
//! # License
//! 
//! Licensed under the MIT license.

use proc_macro::TokenStream;
use proc_macro_error::proc_macro_error;
use syn::DeriveInput;

mod derive;

/// The main trait of the library.
/// 
/// ## Examples
/// 
/// ```
/// use custom_attrs::CustomAttrs;
/// 
/// // ...
/// 
/// #[derive(CustomAttrs)]
/// 
/// // set the attributes
/// #[attr(pub a: usize)]
/// #[attr(b: Option<usize>)] // attributes can be optional
/// #[attr(c: &'static str = "Hello world!")] // and can also have default values
/// enum Enum {
///     #[attr(a = 5)]
///     #[attr(b = 3)]
///     Variant1,
/// 
///     #[attr(a = 3)]
///     #[attr(c = "Hello again !")]
///     Variant2,
/// }
/// 
/// fn main() {
///     let a = Enum::Variant1.get_a();
/// }
/// ```
/// 
/// See the examples directory for more details.
#[proc_macro_derive(CustomAttrs, attributes(attr))]
#[proc_macro_error]
pub fn derive_custom_attrs(input: TokenStream) -> TokenStream {
    let derive_input = syn::parse_macro_input!(input as DeriveInput);

    derive::derive_custom_attrs(derive_input).into()
}