日: 2017年2月11日

defmodule MyList do

  def map([], _func), do: []
  def map([head|tail], func), do: [func.(head) | map(tail, func)]

  def reduce([], value, _func) do
    value
  end
  def reduce([head|tail], value, func) do
    reduce(tail, func.(head, value), func)
  end

  def span(from, to) when from == to, do: [to]
  def span(from, to), do: [from | span(from + 1, to)]

end

^o^ > iex practice_7_4.exs
Eshell V8.0  (abort with ^G)
Interactive Elixir (1.3.4) - press Ctrl+C to exit (type h() ENTER for help)
iex(1)> MyList.span(3, 7)
[3, 4, 5, 6, 7]

map も reduce も使ってないな。