Attribute Macros

These are the same as Procedural Macros except:

• Allow you to create new attributes
• Can be applied to more than just structs and enums
• Don't use derive

Example

#![allow(unused)]
fn main() {
#[route(GET, "/")]
fn index(){}
}

This would be defined like

#![allow(unused)]
fn main() {
#[proc_macro_attribute]
pub fn route(attr: TokenStream, item: TokenStream) -> TokenStream {
}

attr Takes in the GET, "/" part, and item takes in the body, which is the function in this case.