catstore_w_find.ex

defmodule Catstore do
  def start() do
    {:ok, store} = Agent.start(fn -> ["Biggles"] end)
    store
  end

  def pr_cats(cats) do
    Enum.each(cats, fn cat -> IO.puts cat end)
  end

  def show_cats(store) do
    Agent.get(store, fn(cats) -> pr_cats(cats) end)
  end

  def seek_cat([],_) do
  end

  def seek_cat([h|t], which_cat) do
     cond do
      h == which_cat ->
        h
      true ->
        seek_cat(t, which_cat)
      end
  end

  def find_cat(store, which_cat) do
    Agent.get(store, fn(cats) -> seek_cat(cats, which_cat) end)
  end

  def add_cat(store, cat) do
    Agent.update(store, fn(cats) -> [ cat | cats] end)
  end
end

c = Catstore.start()
Catstore.show_cats(c)
Catstore.add_cat(c, "Lulu")
Catstore.show_cats(c)
w = Catstore.find_cat(c, "Lulu")
IO.puts "Cat #{w}"
no_cat = Catstore.find_cat(c, "Zany")
# Not one here
IO.puts "Cat #{no_cat}"