shdblowers

tmux ls && read tmux_session && tmux attach -t ${tmux_session:-default} || tmux new -s ${tmux_session:-default}

shdblowers

JSONPrinter.print(~s/{"hello": "goodbye"}/)

shdblowers

defmodule JSONPrinter do
  use FilePrinter
  
  @behaviour FilePrinter

  @impl FilePrinter
  def parse(str), do: {:ok, "some json " <> str} # ... parse JSON
	
  @impl FilePrinter
  def extensions, do: ["json"]

shdblowers

defmodule FilePrinter do
  @callback parse(String.t) :: {:ok, term} | {:error, String.t}
  @callback extensions() :: [String.t]
  
  defmacro __using__(_opts) do
    quote do
      def output(parsed_str) do
        IO.puts(parsed_str)
      end

shdblowers

defmodule Parser do
  @callback parse(String.t) :: {:ok, term} | {:error, String.t}
  @callback extensions() :: [String.t]
end

defmodule JSONParser do
  @behaviour Parser

  def parse(str), do: {:ok, "some json " <> str} # ... parse JSON
  def extensions, do: ["json"]

shdblowers

defprotocol Size do
  @doc "Calculates the size (and not the length!) of a data structure"
  def size(data)
end

defimpl Size, for: BitString do
  def size(string), do: byte_size(string)
end

defimpl Size, for: Map do

shdblowers

Elixir LDN Key Takeaways

IEx Helpers and Breakpoints

Jose Valim talk about features of Elixir 1.5

Release announcement

• break!
• open

shdblowers

defmodule GherkinTests.Contexts.EditUser do
  use WhiteBread.Context
  
  alias GherkinTests.State
  
  given_ ~r/^I register a new user called "(?<name>[^"]+)"$/,
  fn state, %{name: name} ->
    user_details = %{name: name, email: "#{name}@example.com", password: "password123"}
    
    user_id = MyApp.register(user_details)

shdblowers

defmodule GherkinTests.State do
  
  def store(state, key, value), do: Map.put(state, key, value)
  
  def retrieve(state, key), do: Map.get(state, key)
  
  def set_if_not_exists(state, key, value) do
    if Map.has_key?(state, key) do
      state
    else

shdblowers

Feature: Changing user details

  Scenario: Changing first name to Bob
    Given I register a new user
    And I change their "name" to "Brian"
    When I change their "name" to "Bob"
    Then their "name" should be "Bob"
    
  Scenario: Changing first name to Charlie
    Given I register a new user