# Test: Non-recursive merge (single level only)
{
  merge_shallow = fun base override =>
    if (std.typeof base) == "record" && (std.typeof override) == "record" then
      let base_fields = std.record.fields base in
      let override_fields = std.record.fields override in

      # Pass 1: iterate base fields
      base_fields
      |> std.array.fold_left
        (fun acc key =>
          let base_value = std.record.get key base in
          if std.record.has_field key override then
            let override_value = std.record.get key override in
            acc |> std.record.insert key override_value
          else
            acc |> std.record.insert key base_value
        )
        {}
      # Pass 2: add override-only fields
      |> (fun merged =>
        override_fields
        |> std.array.fold_left
          (fun acc key =>
            if !(std.record.has_field key base) then
              acc |> std.record.insert key (std.record.get key override)
            else
              acc
          )
          merged
      )
    else
      if (std.typeof override) == "null" then base else override,
}