Exploratory investigation of methods of creating dice rolls (first spike)

dice.ex

defmodule Dice do
  @moduledoc """
  Fragile function that turns a string into a list of rolls - _e.g._
  
    > Dice.roll("2d6")
    [4, 3]
    > Dice.roll("d12")
    [11]
  """

  def roll(str) do
    case String.split(str, "d") do
      ["", sides] -> roll(1, String.to_integer(sides))
      [n, sides]  -> roll(String.to_integer(n), String.to_integer(sides))
      _           -> {:error, "some incorrect input"}
    end
  end
  
  def roll(n, sides) do
    1..n |> Enum.map(fn _ -> Enum.random(1..sides) end)
  end
end

roll.ex

defmodule Roll do
  @moduledoc """
  Creates a series of functions of the form `d{sides}(number_of_rolls)`.
  Creates `Roll.d3\1`, `Roll.d4\1`, `Roll.d6\1`, `Roll.d8\1`, `Roll.d10\1`, `Roll.d12\1`, `Roll.d20\1`
  
    > Roll.d3(2)
    [1, 3]
    > Roll.d6(6)
    [3, 4, 4, 2, 6, 5]
  """

  [3,4,6,8,10,12,20] |> Enum.each(fn sides ->
    def unquote(:"d#{sides}")(n \\ 1) do
      1..n |> Enum.map(fn _ -> Enum.random(1..unquote(sides)) end)
    end
  end)
end