pragdave

# Interpret the Ansible log for humans. In particular, we
# look for command executions and format their content
#
#     - name: list files
#       shell: "ls -lrt *e*"
#
# Might produce
#
#       TASK: [1] ***********************************************************
#       changed: [localhost]

pragdave

defmodule RomanNumeral do
  @mapping [
    {1000, 'M'},
    {900,  'CM'},
    {500,  'D'},
    {400,  'CD'},
    {100,  'C'},
    {90,   'XC'},
    {50,   'L'},
    {40,   'XL'},

pragdave

[elixir/Book] svn commit -m 'prep for 0.15'                                                                       [Book:158836]
Sending        Changes.pml
Sending        Enumeration.pml
Sending        Introduction.pml
Sending        Nodes.pml
Sending        OTP-applications.pml
Sending        OTP-servers.pml
Sending        OTP-supervisors.pml
Sending        Project.pml
Sending        Protocols.pml

pragdave

defmodule FibAgent do

  defstruct cache: nil, highest_n: 0

  def start_link do
    initial_cache = Enum.into([ {0, 0}, {1, 1}], HashDict.new)
    state = %__MODULE__{cache: initial_cache, highest_n: 1}
    Agent.start_link(fn -> state end, name: __MODULE__)
  end

pragdave

#
# Given a list, return a new list with all occurrences of consecutive 
# duplicated elements replaced by `{element, count}`
#
#    compress [ 1,2,2,3,4,4,4,5,6,6]
#        → [1, {2, 2}, 3, {4, 3}, 5, {6, 2}]
#

# This version uses the head of the result to give the effect of lookahead

pragdave

defmodule Bitmap do
  defstruct value: 0

end

defimpl Access, for: Bitmap do
  use Bitwise
   def access(%Bitmap{value: value}, bit) do
    if (value &&& (1 <<< bit)) == 0, do: 0, else: 1    
  end

pragdave

defmodule Bitmap do
  defstruct value: 0

  defimpl Access do
    use Bitwise
    def access(%Bitmap{value: value}, bit) do
      if (value &&& (1 <<< bit)) == 0, do: 0, else: 1
    end
  end

pragdave

defmodule Reflect do
  use Application.Behaviour

  def run do
    path = :code.lib_dir(:elixir, :ebin)
    load_modules_in(path)
    modules = for {name,_} <- :code.all_loaded, 
                  Regex.match?(~r/^[A-Z]/, atom_to_binary(name)), 
              do: name

pragdave

defimpl Enumerable, for: Bitmap do
  import :math, only: [log: 1]

  def reduce(bitmap, {:cont, acc}, fun) do
    bit_count =  Enum.count(bitmap)
    _reduce({bitmap, bit_count}, { :cont, acc }, fun)
  end

  defp _reduce({_bitmap, -1}, { :cont, acc }, _fun), do: { :done, acc }
                     

pragdave

defmodule Test do
  def fred, do: 1
end