Macro impl_sv

macro_rules! impl_sv {
    ($ft:literal, $name:ident, $op:ident, $oty:ty, $ity:ident, $ibs:expr) => { ... };
    ($ft:literal, $name:ident, $op:ident, $oty:ty, $ity:ident, $ibs:expr, const) => { ... };
}