Macro naga::proc::constant_evaluator::gen_component_wise_extractor

macro_rules! gen_component_wise_extractor {
    (
        $ident:ident -> $target:ident,
        literals: [$( $literal:ident => $mapping:ident: $ty:ident ),+ $(,)?],
        scalar_kinds: [$( $scalar_kind:ident ),* $(,)?],
    ) => { ... };
}