thebugcatcher

# Given an input, this program returns a list of all primes numbers less than the input. 

defmodule NPrimes do
  def get_primes(n) when n < 2, do: []
  def get_primes(n), do: Enum.filter(2..n, &is_prime?(&1))

  defp is_prime?(n) when n in [2, 3], do: true
  defp is_prime?(x) do
    start_lim = div(x, 2)
    Enum.reduce(2..start_lim, {true, start_lim}, fn(fac, {is_prime, upper_limit}) ->