CODEWITHSUNDEEP
elixirphoenix-framework
Ole Spaarmann
Ole Spaarmann

Reputation: 16771

What is the difference between these two module definitions?

Regarding the Phoenix Framework: I was just wondering what the difference is between writing

defmodule MyApp.User do
  # some code
end

and just

defmodule User do
  # some code
end

later on it would be easier to just write User.function than MyApp.User.function

Upvotes: 1

Views: 106

Answers (2)

coderVishal
coderVishal

Reputation: 9109

It can be applied with the concept of nesting in elixir. Often you would like group a certain modules according to their functionality or just for the sake of naming convinence. Here is a straight example from the docs

defmodule Foo do
  defmodule Bar do
  end
end

Which is same as 

defmodule Elixir.Foo do
  defmodule Elixir.Foo.Bar do
  end
  alias Elixir.Foo.Bar, as: Bar
end

It is important to note that in Elixir,there is no need to define the Outer module to able to use Outer.Inner module name, as the language translates all module names to atoms anyway. You can define arbitrarily-nested modules without defining any module in the chain (e.g., Foo.Bar.Baz without defining Foo or Foo.Bar first).

A solid example is available at the elixir docs.

Upvotes: 1

Gazler
Gazler

Reputation: 84180

This is namespacing you module to avoid clashes. Imagine a scenario where you call your module User and then user a library called user which also defines a User module. You would have a collision.

You can alias in modules that use your User module though:

defmodule MyApp.SomeModule do
  alias MyApp.User

  def foo do
    User.some_function
  end
end

Upvotes: 6

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