Elixir Enumerable for binaries....

Benum.ex

defmodule Benum do
  defimpl Enumerable, for: BitString do
    def count(collection) when is_binary(collection) do
      {:ok, Enum.reduce(collection, 0, fn v, acc -> acc + 1 end)}
    end
    def count(collection) do
      {:error, __MODULE__}
    end
    def member?(collection, value) when is_binary(collection) do
      {:ok, Enum.any?(collection, fn v -> value == v end)}
    end
    def member?(collection, value) do
      {:error, __MODULE__}
    end

    def reduce(b,     {:halt, acc}, _fun) when is_binary(b) do
      {:halted, acc}
    end
    def reduce(b,  {:suspend, acc}, fun) when is_binary(b) do
      {:suspended, acc, &reduce(b, &1, fun)}
    end
    def reduce(<<>>,  {:cont, acc}, _fun) do
      {:done, acc}
    end
    def reduce(<<h :: bytes-size(1), t :: binary>>, {:cont, acc}, fun) do
      reduce(t, fun.(h, acc), fun)
    end
  end
end

# USAGE EXAMPLES
# NOTE: IN ORDER TO GET THIS TO WORK I HAD TO USE MIX_ENV=prod (for protocol consolidation)
# the easier way to do this is to add the following line to your project definition in mix.exs:
#     consolidate_protocols: true,

$ MIX_ENV=prod iex -S mix

iex>> import Benum

iex>> Enum.count "foobar"
6
iex>> Enum.count <<1,2,3>>
3
iex>> Enum.count ""
0

iex>> Enum.member? "foobar", "b"
true
iex>> Enum.member? "foobar", <<98>>
true
iex>> Enum.member? "foobar", "x"
false

iex>> Enum.map("foobar", &String.upcase/1) |> Enum.into <<>>
"FOOBAR"

iex>> Enum.join "foobar", "."
"f.o.o.b.a.r"