<Enjoy-Elixir>mix.exsにいて少し詳しく

# mix コマンドで新しいElixirプロジェクトを作成
$ mix new example
$ cd example
$ ls -1
README.md
lib
mix.exs   ** これがデフォルトのmix.exsです **
test

defmodule Jason.Mixfile do
  use Mix.Project

  @source_url "https://github.com/michalmuskala/jason"
  @version "1.2.2"

  def project() do
    [
      app: :jason,
      version: @version,
      elixir: "~> 1.4",
      start_permanent: Mix.env() == :prod,
      consolidate_protocols: Mix.env() != :test,
      deps: deps(),
      preferred_cli_env: [docs: :docs],
      dialyzer: dialyzer(),
      description: description(),
      package: package(),
      docs: docs()
    ]
  end

  def application() do
    [
      extra_applications: []
    ]
  end

  defp deps() do
    [
      {:decimal, "~> 1.0 or ~> 2.0", optional: true},
      {:dialyxir, "~> 1.0", only: [:dev, :test], runtime: false},
      {:ex_doc, ">= 0.0.0", only: :dev, runtime: false},
    ] ++ maybe_stream_data()
  end

  defp maybe_stream_data() do
    if Version.match?(System.version(), "~> 1.5") do
      [{:stream_data, "~> 0.4", only: :test}]
    else
      []
    end
  end

  defp dialyzer() do
    [
      ignore_warnings: "dialyzer.ignore",
      plt_add_apps: [:decimal]
    ]
  end

  defp description() do
    """
    A blazing fast JSON parser and generator in pure Elixir.
    """
  end

  defp package() do
    [
      maintainers: ["Michał Muskała"],
      licenses: ["Apache-2.0"],
      links: %{"GitHub" => @source_url}
    ]
  end

  defp docs() do
    [
      main: "readme",
      name: "Jason",
      source_ref: "v#{@version}",
      canonical: "http://hexdocs.pm/jason",
      source_url: @source_url,
      extras: ["README.md", "CHANGELOG.md", "LICENSE"]
    ]
  end
end

defmodule Example.MixProject do
  use Mix.Project

  def project do
    [
      app: :example,
      version: "0.1.0",
      elixir: "~> 1.12",
      start_permanent: Mix.env() == :prod,
      deps: deps()
    ]
  end

  # Run "mix help compile.app" to learn about applications.
  def application do
    [
      extra_applications: [:logger]
    ]
  end

  # Run "mix help deps" to learn about dependencies.
  defp deps do
    [
      # {:dep_from_hexpm, "~> 0.3.0"},
      # {:dep_from_git, git: "https://github.com/elixir-lang/my_dep.git", tag: "0.1.0"}
    ]
  end
end

defmodule Jason.Mixfile do
  use Mix.Project
  #
  # ... 省略
  #
end

defmodule Example.MixProject do
  use Mix.Project
  #
  # ... 省略
  #
end

defmodule Jason.Mixfile do
  use Mix.Project
  #
  # ... 省略
  #
end

# Mix.Project module

@doc false
defmacro __using__(_) do
  quote do
    @after_compile Mix.Project
  end
end

# Invoked after each Mix.Project is compiled.
@doc false
def __after_compile__(env, _binary) do
  push(env.module, env.file)
end

defmodule Jason.Mixfile do
  use Mix.Project
  #
  # ... 省略
  #
end

defmodule Example.MixProject do
  use Mix.Project

  def project do
    [
      app: :example,
      version: "0.1.0",
      elixir: "~> 1.12",
      start_permanent: Mix.env() == :prod,
      deps: deps()
    ]
  end

  # ...省略
end

defmodule Example.MixProject do
  use Mix.Project

  def project do
    [
      app: :example,
      version: "0.1.0",
      elixir: "~> 1.12",
      start_permanent: Mix.env() == :prod,
      deps: deps(),
      hello: "world"
    ]
  end

  # ...省略
end

$ iex -S mix
iex> Mix.Project.config[:hello]
"world"
iex> Mix.Project.config
[
  aliases: [],
  build_embedded: false,
  build_per_environment: true,
  build_scm: Mix.SCM.Path,
  config_path: "config/config.exs",
  consolidate_protocols: true,
  default_task: "run",
  deps_path: "deps",
  elixirc_paths: ["lib"],
  erlc_paths: ["src"],
  erlc_include_path: "include",
  erlc_options: [],
  lockfile: "mix.lock",
  preferred_cli_env: [],
  app: :example,
  version: "0.1.0",
  elixir: "~> 1.12",
  start_permanent: false,
  deps: [],
  hello: "world"
]

$ iex -S mix
** (UndefinedFunctionError) function Example.MixProject.project/0 is undefined (function not availabl
e)
    Example.MixProject.project()
    (mix 1.12.1) lib/mix/project.ex:792: Mix.Project.get_project_config/1
    (mix 1.12.1) lib/mix/project.ex:114: Mix.Project.push/3
    (stdlib 3.15.1) lists.erl:1267: :lists.foldl/3
    (stdlib 3.15.1) erl_eval.erl:685: :erl_eval.do_apply/6

defmodule Jason.Mixfile do
  use Mix.Project

  @source_url "https://github.com/michalmuskala/jason"
  @version "1.2.2"

  def project() do
    [
      app: :jason,
      version: @version,
      elixir: "~> 1.4",
      start_permanent: Mix.env() == :prod,
      consolidate_protocols: Mix.env() != :test,
      deps: deps(),
      preferred_cli_env: [docs: :docs],
      dialyzer: dialyzer(),
      description: description(),
      package: package(),
      docs: docs()
    ]
  end

  # ... 省略
end

  # Run "mix help compile.app" to learn about applications.
  def application do
    [
      extra_applications: [:logger]
    ]
  end

defmodule Logger.MixProject do
  use Mix.Project

  def project do
    [
      app: :logger,
      version: System.version(),
      build_per_environment: false
    ]
  end

  def application do
    [
      registered: [Logger, Logger.BackendSupervisor, Logger.Supervisor, Logger.Watcher],
      mod: {Logger.App, []},
      env: [
        utc_log: false,
        truncate: 8096,
        backends: [:console],
        translators: [{Logger.Translator, :translate}],
        sync_threshold: 20,
        discard_threshold: 500,
        handle_otp_reports: true,
        handle_sasl_reports: false,
        discard_threshold_periodic_check: 30_000,
        discard_threshold_for_error_logger: 500,
        compile_time_purge_matching: [],
        compile_time_application: nil,
        translator_inspect_opts: [],
        console: [],
        start_options: []
      ]
    ]
  end
end

defmodule Logger.App do
  @moduledoc false

  require Logger

  use Application

  @doc false
  def start(_type, _args) do
    start_options = Application.get_env(:logger, :start_options)
    otp_reports? = Application.fetch_env!(:logger, :handle_otp_reports)
    counter = :counters.new(1, [:atomics])

    children = [
      %{
        id: :gen_event,
        start: {:gen_event, :start_link, [{:local, Logger}, start_options]},
        modules: :dynamic
      },
      {Logger.Watcher, {Logger.Config, counter}},
      Logger.BackendSupervisor
    ]

    case Supervisor.start_link(children, strategy: :rest_for_one, name: Logger.Supervisor) do
      {:ok, sup} ->
        primary_config = add_elixir_handler(otp_reports?, counter)

        default_handlers =
          if otp_reports? do
            delete_erlang_handler()
          else
            []
          end

        handlers = [{:primary, primary_config} | default_handlers]
        {:ok, sup, handlers}

      {:error, _} = error ->
        error
    end
  end

  @doc false
  def start do
    Application.start(:logger)
  end

  # ... 省略
end

defmodule Issues.Mixfile do
  use Mix.Project

  def project do
    [
      app: :issues,
      version: "0.0.1",
      elixir: "~> 1.2",
      build_embedded: Mix.env == :prod,
      start_permanent: Mix.env == :prod,
      deps: deps
    ]
  end

  def application do
    [
      applications: [:logger, :httpoison]
    ]
  end

  defp deps do
    [
      { :httpoison, "~> 0.8" }
    ]
  end
end

defmodule Issues.Mixfile do
  use Mix.Project

  def project do
    [
      app: :issues,
      version: "0.0.1",
      elixir: "~> 1.4",
      build_embedded: Mix.env == :prod,
      start_permanent: Mix.env == :prod,
      deps: deps
    ]
  end

  def application do
    [
      extra_applications: [:logger]
    ]
  end

  defp deps do
    [
      { :httpoison, "~> 0.8" }
    ]
  end
end