Macro impl_rarray_try_from_sexp_coerce 

macro_rules! impl_rarray_try_from_sexp_coerce {
    ($source:ty => $target:ty) => { ... };
}

Implement TryFromSexp for RArray<$target, NDIM> by reading R’s native $source type.

The RArray wraps the source SEXP directly. Use to_vec_coerced() to get coerced data.