Macro builder

macro_rules! builder {
    ($(#[derive($($d:ident),+)])?$name:ident::<$inner:ty> {$($k:ident: $v:ty),* $(,)?}) => { ... };
    ($(#[derive($($d:ident),+)])? $name:ident($inner:ty) {$($k:ident: $v:ty),* $(,)?}) => { ... };
    (@loop builder: $name:ident, derive: [$($d:ident),* $(,)?], inner: $inner:ty {$($k:ident: $v:ty),* $(,)?}) => { ... };
    (@impl builder: $name:ident, inner: $inner:ty {$($k:ident: $v:ty),* $(,)?}) => { ... };
}