eval.ex

defp evaluate(message, code) do
    result = try do
      {result, _} = Code.eval_string(code, [message: message], __ENV__)
      result
    rescue
      e -> e
    end
  end

  defp eval_embed(input, output) do
    code_block = fn code ->
      "```elixir\n" <> code <> "\n```"
    end
    %Embed{}
    |> field("Input:", code_block.(input))
    |> field("Output:", code_block.(output))
  end

  Cogs.set_parser(:eval, fn string ->
    string
    |> String.split(["```\n", "\n```"])
    |> Enum.drop(1)
  end)
  # waits 5s for a result
  Cogs.def eval(code) do
    task = Task.async(fn -> evaluate(message, code) end)
    case Task.yield(task) || Task.shutdown(task) do
      {:ok, result} ->
        embed = eval_embed(code, Macro.to_string(result)) |> build
        Client.edit_message(message, "", embed: embed)
      nil ->
        embed = eval_embed(code, "Process took over 5s to yield a result.") |> build
        Client.edit_message(message, "", embed: embed)
    end
  end
  Cogs.def eval, do: nil