sigil_MapSet.ex

  @doc """
  The MapSet sigil.

      iex> ~MapSet{1, 2, [3, 4], ~MapSet[5]}
      #MapSet<[1, 2, #MapSet<[5]>, [3, 4]]>

      # but this of course wouldn't work due to sigil delimiter escaping:
      # iex> ~MapSet{1, ~MapSet{2}}

  """
  defmacro sigil_MapSet({:<<>>, _, [string]}, []) do
    quoted = Code.string_to_quoted!("[" <> string <> "]")

    quote do
      MapSet.new(unquote(quoted))
    end
  end