Function flatten

datafusion/common/src/scalar/mod.rs:835–846

(array: &'a StructArray, columns: &mut Vec<&'a ArrayRef>)

}

fn flatten<'a>(array: &'a StructArray, columns: &mut Vec<&'a ArrayRef>) {
    for i in 0..array.num_columns() {
        let column = array.column(i);
        if let Some(nested_struct) = column.as_any().downcast_ref::<StructArray>() {
            // If it's a nested struct, recursively expand
            flatten(nested_struct, columns);
        } else {
            // If it's a primitive type, add directly
            columns.push(column);
        }
    }
}

pub fn partial_cmp_struct(s1: &StructArray, s2: &StructArray) -> Option<Ordering> {
    if s1.len() != s2.len() {