ostap

ostap

In Phoenix apps, the web module provides this “re-dispatch into methods” technique for use (see __using__):

defmodule ExampleWeb.Router do
  use ExampleWeb, :router
end

defmodule ExampleWeb.TodoController do
  use ExampleWeb, :controller
end

defmodule ExampleWeb.Layouts do
  use ExampleWeb, :html
end

defmodule ExampleWeb do
  @doc """
  When used, dispatch to the appropriate controller/live_view/etc.
  """
  defmacro __using__(which) when is_atom(which) do
    apply(__MODULE__, which, [])
  end

  def router do
    #
  end

  def controller do
    quote do
      # ...
    end
  end

  def html do
    quote do
      # ...
    end
  end
end

What was the goal/benefit behind doing it that way? I’m guessing it’s for cutting on boilerplate, as otherwise it would’ve been:

defmodule ExampleWeb.TodoController do
  use ExampleWeb.Controller
end

defmodule ExampleWeb.Layouts do
  use ExampleWeb.HTML
end

defmodule ExampleWeb.Router do
  # hmm, probably inlined because same module name
end

defmodule ExampleWeb.Controller do
  defmacro __using__ do
    # ...
  end
end


defmodule ExampleWeb.HTML do
  defmacro __using__ do
    # ...
  end
end

Do we see more examples of this technique being used in libraries and projects besides Phoenix?

I’m trying to grasp the philosophy behind every decision :sweat_smile:

Showing Posts 1 to 2

Eiji

Eiji

I think it’s rather an edge case especially to make code “shorter” and have a single “helper” module for this. It’s most probably because this code is not a part of a hex package, but a simple and short not documented (private functions have no documentation) part of your codebase. They are short and contains just a few aliases/imports and stuff like that. I would say it would be divided in few modules only if the inside logic would be more complex than what we have right now.

The entire ExampleWeb module logic is just so simple that it can’t compare to the logic of a typical macro. Also I believe it’s easier to maintain such helper in a single file rather than working on multiple files. The current Phoenix version have already impressive structure and does not need a bunch of tiny files just to separate such a simple logic.

ostap

ostap OP

Thank you! Interestingly, even Phoenix 1.0 from 2015 already shipped with the same web module, while the pre-release version from 2014 didn’t have it and used the alternative “separate modules” approach.

— All posts loaded —

Where Next? Top

Trending in Questions Top

RSP87
I’m working on a project that simulates the bumbl example in the programming phoenix book. It acts almost like an email client. We have a...
New
nseaSeb
Hello, I know there is an approach for handling lists that allows for optimized traversal, but I can’t recall the specific method (somet...
New
RemyXRenard
I’m seeing that a list inside a Kino.DataTable will be interpreted as a charlist, even if the Kino.configure() is set to charlists: :as_l...
New
velrest
So my question is quite simple and i have found no conclusive answer on forum, google or AI. Should we use :erlang.float for Integer to ...
New
brecabral
Documentation While reading the Scoped Routes section, I noticed that the documentation currently refers to a problem without explainin...
New
samoloth
Hi, I’ve just set up an application with ash_authentication. There is only magic link strategy for now, so there is no confirmation add o...
New
FlyingNoodle
If a change or preparation module uses Ash.Changeset.get_argument/2 or Ash.Query.get_argument/2 (or any of the other get_argument functio...
New

Other Trending Topics Top

mudasobwa
I am happy to introduce the very α version of the new programming language compiled to BEAM. Welcome Cure. It has literally three kille...
New
marciok
Hi there! We created Gust: A task orchestrator inspired by Airflow. For those who have never heard about Aiflow, it’s a Python-based wor...
New
jimsynz
Beam Bots (or just BB for short) is a framework for building fault-tolerant robotics applications in Elixir using familiar OTP patterns. ...
New
Dmk
Xamal is a deployment tool for Elixir apps that deploys native releases to bare metal servers over SSH. It’s a port of GitHub - basecamp/...
New
netoum
Corex is an accessible, unstyled UI component library for Phoenix that integrates Zag.js state machines using Vanilla JavaScript and Live...
New
webofbits
With AI doing more of the implementation work, I’ve been wondering how much coding I should deliberately keep doing myself. My main conc...
#ai
New

We're in Beta

About us Mission Statement

Options

Thread Display Mode




Thread Preview

Skip Thread Previews