blatyo

TL;DR Add field punning to maps in Elixir

• Background
  • What is Field Punning?
  • Field Punning in Elixir
  • Package Implementations and Shortcomings
• Proposal
  • Creating Maps
  • Creating Structs
• Updating Maps

blatyo

defmodule LoginService do

def call(attrs) do
  with {:ok, profile_id} <- login_with_auth(attrs),
       {:ok, user} <- lookup_user(profile_id) do
    send_user_refresh_request(user)
    {:ok, %Authentication{id: user.id, user: user}}
  else
    error -> error
  end

blatyo

defmodule P do
  defmacro __using__(_opts) do
    quote do
      import P
      Module.register_attribute(__MODULE__, :plugs, accumulate: true)
      @before_compile P
    end
  end

  defmacro __before_compile__(env) do

blatyo

import Ember from 'ember';

export default Ember.Controller.extend({
  appName: 'Ember Twiddle'
});

blatyo

  1) test .process with no meta it creates a message record (WireTap.MessageConsumerTest)
     test/consumers/message_consumer_test.exs:35
     match (=) failed
     The following variables were pinned:
       message_body = %{"action_code" => 4, "institution_id" => "INS-3887fd5a-6e00-90ce-06f0-3e446c0233a3", "job" => %{"checked_at" => "2016-08-03T12:53:05.942Z[Etc/UTC]", "created_at" => "2016-08-03T12:52:36Z[Etc/UTC]", "finished_at" => "2016-08-03T12:53:05Z[Etc/UTC]", "job_id" => "JOB-d2011b94-423a-eebe-6f98-cf370558d029", "job_status" => %{"job_status_id" => 6, "job_status_name" => "COMPLETED"}, "started_at" => "2016-08-03T12:52:36Z[Etc/UTC]", "updated_at" => "2016-08-03T12:53:05Z[Etc/UTC]"}, "member_id" => "MBR-95b5b0d9-f315-7930-1975-a97eaafa1a6f", "previous_job_status" => %{"job_status_id" => 4, "job_status_name" => "TRANSFERRED"}, "ready_for_import" => true}
       meta = %{}
     code: %{correlation_id: nil, created_at: _, event: "updated", id: _, message: ^message_body, meta: ^meta, producer: "mx", pr

blatyo

import Ember from 'ember';

export default Ember.Controller.extend({
  appName: 'Ember Twiddle'
});

blatyo

import Ember from 'ember';

export default Ember.Controller.extend({
  appName: 'Ember Twiddle'
});

blatyo

import Ember from 'ember';

export default Ember.Component.extend({
  actions: {
    callParent() {
      this.sendAction('callParent', this.get('name'));
    }
  }
});

blatyo

defmodule MessageRouter.DSL do
  alias MessageRouter.Route
  alias MessageRouter.QueueHandler
  alias MessageRouter.Supervisor

  defmacro __using__(_args) do
    quote do
      import MessageRouter.DSL

      Module.register_attribute(__MODULE__, :routes, accumulate: true)

blatyo

def execute(command, logger)
  require 'open3'
  _, stdout, stderr, process = Open3.popen3(command)

  unless process.value.success?
    logger.error(command)
    logger.error(stdout.read)
    logger.error(stderr.read)

    exit process.value.exitstatus