udzura

defmodule Hygiene do
  defmacro interference do
    quote do: var!(a) + var!(b) + var!(c)
  end
end

defmodule HygieneTest do
  def go do
    require Hygiene
    a = 10

manpages

iex(14)> f = function do 
...(14)>  (do: anything) -> anything
...(14)>  (_) -> :nothing
...(14)> end
#Fun<erl_eval.6.82930912>
iex(15)> f.(do: 42)
42
iex(16)> f.(do
...(16)>   answer = 42
...(16)>   answer

alco

iex(8)> Regex.run %r/^~(\d)+\.\.[0 ]B$/, "~4..0B"                    
["~4..0B", "4"]
iex(9)> Regex.run %r/^~(\d)+\.\.[0 ]B$/, "~4..0B", capture: :groups  
** (ArgumentError) regex was not compiled with g
    /Users/alco/Documents/git/elixir/lib/elixir/lib/regex.ex:134: Regex.run/3
    erl_eval.erl:569: :erl_eval.do_apply/6
    src/elixir.erl:138: :elixir.eval_forms/3

iex(9)> Regex.run %r/^~(\d)+\.\.[0 ]B$/g, "~4..0B", capture: :groups
[]

alco

defmodule L do
  # lc x inlist [0, 1], y inlist [:a, :b], do: {x, y}
  defmacro do_list(list) do
    args = 1..length(list)
    |> Enum.map(fn x -> binary_to_atom(<<?a + x :: utf8>>) end)
    |> Enum.map(fn x -> {x, [], :Elixir} end)  # this creates AST nodes for variables

    pairs = Enum.zip(args, list)
    |> Enum.map(fn {v, lst} ->
      quote do

darkofabijan

iex(33)> Code.eval_quoted(quote do: [unquote_splicing([{4, "show/:id"}])])
{[{4, "show/:id"}], []}

iex(34)> Code.eval_quoted(quote do: [unquote_splicing([{4, "show/:id", 1, 2}])])
** (CompileError) nofile: invalid quoted expression: {4, "show/:id", 1, 2}
    (elixir) src/elixir_exp.erl:408: :elixir_exp.expand_arg/2
    (elixir) src/elixir_exp.erl:384: :elixir_exp.expand_list/4
    (elixir) src/elixir_exp.erl:358: :elixir_exp.expand/2
    (elixir) src/elixir.erl:150: :elixir.quoted_to_erl/3
    (elixir) src/elixir.erl:134: :elixir.eval_forms/4

zsoldosp

$ elixir macros-why-error.exs
false
** (UndefinedFunctionError) undefined function: MyMacro.unless/2
    MyMacro.unless(false, [do: :ok])
    (elixir) src/elixir_lexical.erl:17: :elixir_lexical.run/2
    (elixir) lib/code.ex:301: Code.require_file/2

rylev

defmodule User do
  defstruct firstname: "Ryan", lastname: "Levick"

  def full_name(user) do
    user.firstname <> " " <> user.lastname
  end
end

user = %User{}
User.full_name(user) =>

alco

defmodule View do
  defrecord Page, [templates: []]

  defmacro __using__(_) do
    template = """
    <%= for template <- page.templates do %>
      <%= template.id %> ::
    <% end %>

    <%= if true do %>

stevedomin

defmodule SimpleDynamoDeploy.Mixfile do
  use Mix.Project

  def project do
    [ app: :simple_dynamo_deploy,
      version: "0.0.1",
      build_per_environment: true,
      dynamos: [SimpleDynamoDeploy.Dynamo],
      compilers: [:elixir, :dynamo, :app],
      deps: deps ]

scrogson

defrecord User, name: "", email: ""

defmodule Amnesia do

  @compile {:parse_transform, :qlc}

  def create_schema do
    create_table User
  end