Attribute Macro macro_derive 

#[macro_derive]

⌗ proc Runs classic derives and declarative derives from one list.

---

^{📍 code/util}

---

Entries ending in ! are called as declarative macros. Other entries are forwarded to Rust’s built-in derive.

The optional helper attribute #[macro_derive_args(...)] may be used to pass item-local arguments to declarative derives.

Examples

macro_rules! derive_name {
   (
       $(#[$meta:meta])*
       $vis:vis struct $Name:ident;
   ) => {
       impl $Name {
           pub const NAME: &'static str = stringify!($Name);
       }
   };
}

#[macro_derive(Debug, Clone, derive_name!)]
struct Thing1;

let thing = Thing1;
let clone = thing.clone();

assert_eq!(Thing1::NAME, "Thing1");
assert_eq!(format!("{clone:?}"), "Thing1");

macro_rules! derive_value {
   (
       #[macro_derive_args($value:expr)]
       $(#[$meta:meta])*
       $vis:vis struct $Name:ident;
   ) => {
       impl $Name {
           pub const VALUE: usize = $value;
       }
   };
}

#[macro_derive(Debug, derive_value!)]
#[macro_derive_args(42)]
struct Thing2;

assert_eq!(Thing2::VALUE, 42);
assert_eq!(format!("{Thing2:?}"), "Thing2");

macro_rules! derive_label {
   (
       ($label:literal)
       $(#[$meta:meta])*
       $vis:vis struct $Name:ident;
   ) => {
       impl $Name {
           pub const LABEL: &'static str = $label;
       }
   };
}

#[macro_derive(Debug, derive_label!("direct"))]
struct Thing3;

assert_eq!(Thing3::LABEL, "direct");
assert_eq!(format!("{Thing3:?}"), "Thing3");

Vendored

This is adapted work from macro_rules_attribute.