macro_rules! dispatch_scalar_variants {
    ($impl:expr, [$($k:ident = $v:ident),*], $body:tt) => { ... };
    ($impl:expr, $inner:pat, $body:tt) => { ... };
    ($impl:expr, $inner:pat, [$($k:ident = $v:ident),*], $body:tt) => { ... };
}Expand description
Dispatch the code block to all variants of ScalarImpl.
Refer to dispatch_array_variants for usage.