Recursive and Tail Recursive Fibonacci in Elixir

Sicp.Fibonacci.ex

defmodule Sicp.Fibonacci do
  def fibonacci(0) do
    0
  end

  def fibonacci(1) do
    1
  end

  def fibonacci(n) do
    fibonacci(n - 1) + fibonacci(n - 2)
  end

  defp fibonacci_tail(_prev, acc, 1) do
    acc
  end

  defp fibonacci_tail(prev_acc, acc, count) do
    fibonacci_tail(acc, prev_acc + acc, count - 1)
  end

  def fib_tail(0) do
    0
  end

  def fib_tail(1) do
    1
  end

  def fib_tail(2) do
    1
  end

  def fib_tail(n) do
    fibonacci_tail(1, 1, n - 1)
  end

  def fib_list(n) do
    for n <- 0..n, do: fibonacci(n)
  end

  def fib_list_tail(n) do
    for n <- 0..n, do: fib_tail(n)
  end
end