josevalim

defmodule OhMy do
  @moduledoc false

  def undefined_function(module, fun, args) do
    :io.format("~p~n", [[module, fun, args]])
    :error_handler.undefined_function(module, fun, args)
  end

  def undefined_lambda(module, fun, args) do
    :io.format("~p~n", [[module, fun, args]])

josevalim

defp escape({ left, meta,  right }) do
  { '{}', meta, [escape(left), meta, escape(right)] }
end

defp escape({ left, right }) do
  { escape(left), escape(right) }
end

defp escape(list) when is_list(list) do
  Enum.map(list, escape(&1))

josevalim

ExUnit.start

defmodule Hello do
  @doc """
  Hello world.
  
  ## Examples
  
      iex> 1 + 2
      3

josevalim

  def zip(a, b) do
    list = to_list(a)

    throw do
      { zipped, rest } = Reducers.reduce(b, { [], list }, fn
        entry, { acc, [h|t] } -> { [{entry, h}|acc], t }
        entry, { acc, [] } -> throw { :enum_zip, acc }
      end)

      :lists.foldl(fn(x, acc) ->

josevalim

About you:

• Name
• University (current enrollment)
• Short bio (overview of your background)
• Phone number
• Address
• Timezone
• IRC nick
• Join the mailing list (send a quick introduction e-mail) and IRC channel (links at http://beamcommunity.github.io/)

josevalim

Flaws in unquote fragments

A couple weeks ago, we have pushed support to unquote fragments:

Enum.each [a: 1, b: 2], fn { k, v } ->
  def map(unquote(k)), do: unquote(v)
end

Although it provide a nice way to dynamically define functions, after discussing with developers and extending Elixir to rely more on it, some flaws became aparent.

josevalim

# rackup -s thin
require 'thin'

run proc { |env|
  body = Enumerator.new do |socket|
    5.times do
      socket << "Hello"
      puts "Hello"
      sleep 1
    end

josevalim

class MyApp < Rails::Application
  routes.append do
    match "*", to: "controller#action"
  end
end

josevalim

# This allows developers to pass an Active Model object
# to within, check and uncheck. This is very useful when
# used with `content_tag_for` since `content_tag_for`
# generates an unique dom id for each object. With this
# module, we can write:
#
#    within comment do
#      click_link "Destroy"
#    end
#

josevalim

Expected:

[
  [{"a","b"},{"c","d"}],
  [{"a1","b1"},{"c1","d1"}],
  [{"a2","b2"},{"c2","d2"}]
]

Actual: