Macro id 

macro_rules! id {
    ($first:ident $(:: $rest:ident)* $(,)?) => { ... };
    ($first:ident $(:: $rest:ident)*, $key:expr $(,)?) => { ... };
}

#[day_pieces::builder(FooBuilder)]: a piece’s builder trait, generated from its inherent impl (docs/api-style.md “Typed builders and erasure”). Declare an ID at its piece, including a link-time catalog entry.

let save = day_core::id!(account::save);
let row = day_core::id!(query_row, 42_u64);
assert_eq!(save.as_str(), "account::save");
assert_eq!(row.as_str(), "query_row:42");

Names are declarations using identifier tokens, with no string or case-conversion path.

let _ = day_core::id!("save");

let _ = day_core::id!(Save);

let _ = day_core::id!(r#save);

let _ = day_core::id!(account__save);

let _ = day_core::id!(type);