defmodule Lists do
  @moduledoc false
  use Koans

  @intro "Lists"

  koan "We can see what is ahead" do
    assert List.first([1, 2, 3]) == ___
  end

  koan "Checking what's trailing is also simple" do
    assert List.last([1, 2, 3]) == ___
  end

  koan "Lists can store anything you throw at them" do
    assert [1, 2] ++ [:a, "b"] == ___
  end

  koan "Things can evolve" do
    assert [1, 2, 3] -- [3] == ___
  end

  koan "Evolution can have different forms" do
    assert List.delete([:a, :b, :c], :b) == ___
  end

  koan "Precision is also valued" do
    assert List.delete_at([:a, :b, :c], 2) == ___
  end

  koan "Replication is also possible" do
    assert List.duplicate("life", 3) == ___
  end

  koan "Sometimes leveling the playing field is desired" do
    assert List.flatten([1, [2, 3], 4, [5]]) == ___
  end

  koan "Order can also be specified for new members" do
    assert List.insert_at([1, 2, 3], 1, 4) == ___
  end

  koan "We can replace things at specified positions" do
    assert List.replace_at([1, 2, 3], 0, 10) == ___
  end

  koan "When a replacement cannot be found, the list remains the same" do
    assert List.replace_at([1, 2, 3], 10, 0) == ___
  end

  koan "Order is bound by nature's laws" do
    assert List.insert_at([1, 2, 3], 10, 4) == ___
  end

  koan "Sometimes it's faster to loop around back" do
    assert List.insert_at([1, 2, 3], -1, 4) == ___
  end

  koan "We can also transform ourselves completely" do
    assert List.to_tuple([1, 2, 3]) == ___
  end

  koan "Wrapping other values is a handy option" do
    assert List.wrap("value") == ___
  end

  koan "Wrapping nothing produces a list of nothing" do
    assert List.wrap(nil) == ___
  end

  koan "When there is already a list do not wrap it again" do
    assert List.wrap(["value"]) == ___
  end
end