Save Game

Mix.install([
  {:jason, "~> 1.4"},
  {:kino, "~> 0.8.0", override: true},
  {:youtube, github: "brooklinjazz/youtube"},
  {:hidden_cell, github: "brooklinjazz/hidden_cell"}
])

Navigation

Return Home Report An Issue

Save Game

Many games have a Save function, which allows players to save the current state of the game. In some cases, the saved game is stored in a save file.

You’re going to implement a Game module which simulates saving a video game’s state using the file system. You should be able to store some arbitrary Elixir term in a given file, and retrieve it.

Example Solution

defmodule Game do
  def save(game_state, filename) do
    File.write!(filename, :erlang.term_to_binary(game_state))
  end

  def load(filename) do
    File.read!(filename) |> :erlang.binary_to_term()
  end
end

Implement the Game module as documented below.

defmodule Game do
  @moduledoc """
  Documentation for `Game`

  ## Examples

      iex> game_state = %{name: "Peter Parker", level: 10, location: "New York"}
      iex> Game.save(game_state, "save_file1")
      :ok
      iex> Game.load("save_file1")
      %{name: "Peter Parker", level: 10, location: "New York"}
  """

  @doc """
  Save an elixir term into a given file name.
  """
  def save(data, filename) do
  end

  @doc """
  Retrieve an elixir term from a given file name.
  """
  def load(filename) do
  end
end

Mark As Completed

file_name = Path.basename(Regex.replace(~r/#.+/, __ENV__.file, ""), ".livemd")

save_name =
  case Path.basename(__DIR__) do
    "reading" -> "save_game_reading"
    "exercises" -> "save_game_exercise"
  end

progress_path = __DIR__ <> "/../progress.json"
existing_progress = File.read!(progress_path) |> Jason.decode!()

default = Map.get(existing_progress, save_name, false)

form =
  Kino.Control.form(
    [
      completed: input = Kino.Input.checkbox("Mark As Completed", default: default)
    ],
    report_changes: true
  )

Task.async(fn ->
  for %{data: %{completed: completed}} <- Kino.Control.stream(form) do
    File.write!(
      progress_path,
      Jason.encode!(Map.put(existing_progress, save_name, completed), pretty: true)
    )
  end
end)

form

Commit Your Progress

Run the following in your command line from the curriculum folder to track and save your progress in a Git commit. Ensure that you do not already have undesired or unrelated changes by running git status or by checking the source control tab in Visual Studio Code.

$ git checkout -b save-game-exercise
$ git add .
$ git commit -m "finish save game exercise"
$ git push origin save-game-exercise

Create a pull request from your save-game-exercise branch to your solutions branch. Please do not create a pull request to the DockYard Academy repository as this will spam our PR tracker.

DockYard Academy Students Only:

Notify your teacher by including @BrooklinJazz in your PR description to get feedback. You (or your teacher) may merge your PR into your solutions branch after review.

If you are interested in joining the next academy cohort, sign up here to receive more news when it is available.

Up Next