Macro define_algorithm_and_builder 

macro_rules! define_algorithm_and_builder {
    (
        $(#[$meta:meta])*
        $algorithm:ident, $selector:ty, $survivor:ty
        $(, selection_args = [ $( $larg:ident : $lty:ty ),* $(,)? ])?
        $(, survival_args  = [ $( $sarg:ident : $sty:ty ),* $(,)? ])?
        $(, shared_survival_args = [ $( $ss:ident : $ssty:ty ),* $(,)? ])?
        , override_build_method = $ov:tt
        $(,)?
    ) => { ... };
    (
        $(#[$meta:meta])*
        $algorithm:ident, $selector:ty, $survivor:ty
        $(, selection_args = [ $( $larg:ident : $lty:ty ),* $(,)? ])?
        $(, survival_args  = [ $( $sarg:ident : $sty:ty ),* $(,)? ])?
        $(, shared_survival_args = [ $( $ss:ident : $ssty:ty ),* $(,)? ])?
        $(,)? // trailing comma opcional
    ) => { ... };
    (@impl
        ($(#[$meta:meta])*) $algorithm:ident, $selector:ty, $survivor:ty,
        selection: [ $( $larg:ident : $lty:ty ),* ],
        survival:  [ $( $sarg:ident : $sty:ty ),* ],
        shared:    [ $( $ss:ident   : $ssty:ty ),* ],
        override_build: $ov:tt
    ) => { ... };
    (@call_selector $ty:ty ; () ) => { ... };
    (@call_selector $ty:ty ; ( $( $a:ident ),+ ) ) => { ... };
    (@call_survivor $ty:ty ; () () ) => { ... };
    (@call_survivor $ty:ty ; ( $( $a:ident ),+ ) () ) => { ... };
    (@call_survivor $ty:ty ; () ( $( $b:ident ),+ ) ) => { ... };
    (@call_survivor $ty:ty ; ( $( $a:ident ),+ ) ( $( $b:ident ),+ ) ) => { ... };
}