__using__ using use

gistfile1.ex

# used from within a test (e.g. use UseDI.A) the following is output:
# __using__ UseDI. caller : Elixir.UseDependencyInjectionTest
# __using__ UseDI.A. caller : Elixir.UseDependencyInjectionTest


import IO, only: [puts: 1]                                                      
                                                                                
defmodule UseDI do                                                              
  defmacro __using__(_) do                                                      
    quote do                                                                    
      puts " __using__ UseDI. caller : #{unquote(__CALLER__.module)}"           
    end                                                                         
  end                                                                           
end                                                                             
                                                                                
defmodule UseDI.A do                                                            
  defmacro __using__(_) do                                                      
    quote do                                                                    
      use UseDI                                                                 
      puts " __using__ UseDI.A. caller : #{unquote(__CALLER__.module)}"         
    end                                                                         
  end                                                                           
end