gistfile1.ex

defmodule Hello do

  def world do
    IO.puts "Hello World"
  end

end

gistfile2.erl

-module(hello).
-export(compile_all).

world() ->
  io:format("Hello World").

gistfile3.ex

Enum.map([1,2,3], fn(x) -> x * 2 end)

gistfile4.erl

lists:map([1,2,3], fun(X) -> X*2 end).