generic_transform.exs

defmodule GenericTransform do

  # Example: transform(list, &list_to_set/1)

  @spec transform(map | list | term, (term -> term)) :: map | list | term
  def transform(map, fun) when is_map(map) do
    Enum.reduce(map, %{}, fn {k, v}, acc ->
      acc
      |> Map.put(k, transform(v, fun))
      |> fun.()
    end)
  end

  def transform(list, fun) when is_list(list) do
    list
    |> Enum.map(&transform(&1, fun))
    |> fun.()
  end

  def transform(term, fun), do: fun.(term)

  def list_to_set(list) when is_list(list) do
    MapSet.new(list)
  end

  def list_to_set(term), do: term
end