Extending an Absinthe schema using custom, app-specific macros

color.ex

defmodule MyApp.Color do

  @moduledoc """
  Just an example source of the values
  """

  def list do
    ~w(red green blue)a
  end
  
end

macros.ex

defmodule MyApp.Schema.Macros do

  @moduledoc """
  App-specific macros to extend the schema
  """

  defmacro color_definitions do
    for color <- MyApp.Color.list() do
      quote do: value unquote(color)
    end
  end

end

schema.ex

defmodule MyApp.Schema do
  use Absinthe.Schema
  
  # Get the macros
  import MyApp.Schema.Macros
  
  enum :colors do
    # Use the macro
    color_definitions()
  end
  
end