# Using the "Use" Elixir Macro

Suppose you have the following module directives in your current module: 
```elixir
  import Ecto.Query
  import Pgvector.Ecto.Query, only: [l2_distance: 2]

  alias MyApp.Podcasts.Episode
  alias MyApp.Prompts.PodcastEpisode
  alias MyApp.Prompts.UserQuestion
   
  require Logger
```
Another module called **MyApp.Subscriber** is using the same exact directives. You don't want to violate the principle of DRY (Don't Repeat Yourself) and hence you figure out that you do not want to do the same thing in the Subscriber module. What can you do about this? 

Here is where some basic **Metaprogramming** skills might come into play. Metaprogramming is basically using code to write code.A combination of **quote** and  **use** macro in Elixir can be used for exactly that. Anytime you *use* a specific module, you are basically calling its **Module.\__using__\()**  macro. 

To eradicate this repetition, define a module e.g MyApp.Meta then :
```elixir 
defmodule MyApp.Meta do
  defmacro __using__(_options) do
    quote do
      import Ecto.Query
      import Pgvector.Ecto.Query, only: [l2_distance: 2]

      alias MyApp.Podcasts.Episode
      alias MyApp.Prompts.PodcastEpisode
      alias MyApp.Prompts.UserQuestion
      
      require Logger
    end
  end
end

```

Quote/2 returns an abstract representation (Abstract Syntax Tree) rather than the expression itself.

Then anywhere you need this directives just do : 

```elixir
  use MyApp.Meta 
```
 


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Created by: Deankinyua
Date: July 15, 2025
URL: https://elixirdrops.net/d/DXwfbtUP