How to exclude compilation of module which is only works on target?

[pojiro]

When developing Nerves codes, which can works on both :host and :target, on host machine, I’d like to exclude compilation of codes which works on only :target. (The codes use “import Nerves.Runtime”, so compilation failed.)

How could I do that?

[mudasobwa]

Put the codes to conditionally compile into the separate folder, e.g. lib_target on the top level.
In your project file mix.exs do the following

  def project do
    [
      ...  
      elixirc_paths: elixirc_paths(Mix.env()),
      ...  
    ]

  defp elixirc_paths(:target), do: ["lib", "lib_target"]
  defp elixirc_paths(_), do: ["lib"]

[pojiro]

@mudasobwa Thank you for your quick reply.

I modify your advice codes for Nerves, like below

  def project do
    [
      ...  
      elixirc_paths: elixirc_paths(Mix.target()),
      ...  
    ]
  end

  defp elixirc_paths(:host), do: ["lib"]
  defp elixirc_paths(target) when target in @all_targets, do: ["lib", "lib_target"]

Thanks a lot !!