Implement Access behaviour since the protocol has been deprecated

lib/array.ex

@@ -1,4 +1,5 @@
 defmodule Array do
+  @behaviour Access
   @moduledoc """
   A wrapper module for Erlang's array.
   """
@@ -15,7 +16,7 @@ defmodule Array do
   Creates a new, extendible array with initial size zero.
   The default value is the atom nil, not undefined.
   """
-  @spec new() :: t 
+  @spec new() :: t
   def new() do
     %Array{content: :array.new({:default, nil})}
   end
@@ -85,7 +86,7 @@ defmodule Array do
 
   @doc """
   Folds the elements of the array using the given function and initial accumulator value.
-  The elements are visited in order from the lowest index to the highest. 
+  The elements are visited in order from the lowest index to the highest.
 
   If `fun` is not a function, the call raises `ArgumentError`.
   """
@@ -96,7 +97,7 @@ defmodule Array do
   @doc """
   Folds the elements of the array right-to-left using the given function and initial accumulator value.
   The elements are visited in order from the highest index to the lowest.
- 
+
   If `fun` is not a function, the call raises `ArgumentError`.
   """
   @spec foldr(t, acc, (index, element, acc -> acc)) :: acc when acc: var
@@ -184,7 +185,7 @@ defmodule Array do
   @doc """
   Maps the given function onto each element of the array.
   The elements are visited in order from the lowest index to the highest.
- 
+
   If `fun` is not a function, the call raises `ArgumentError`.
   """
   @spec map(t, (index, element -> any)) :: t
@@ -260,7 +261,7 @@ defmodule Array do
   Folds the elements of the array right-to-left using the given function and initial accumulator value,
   skipping default-valued entries.
   The elements are visited in order from the highest index to the lowest.
- 
+
   If `fun` is not a function, the call raises `ArgumentError`.
   """
   @spec sparse_foldr(t, acc, (index, element, acc -> acc)) :: acc when acc: var
@@ -270,7 +271,7 @@ defmodule Array do
   @doc """
   Maps the given function onto each element of the array, skipping default-valued entries.
   The elements are visited in order from the lowest index to the highest.
- 
+
   If `fun` is not a function, the call raises `ArgumentError`.
   """
   @spec sparse_map(t, (element -> any)) :: t
@@ -320,16 +321,45 @@ defmodule Array do
   @spec to_orddict(t) :: [{index, element}]
   def to_orddict(%Array{content: c}),
     do: :array.to_orddict(c)
-end
 
-defimpl Access, for: Array do
-  def get(arr, idx) do
-    Array.get(arr, idx)
+  @doc """
+  Access behavior `fetch/2` callback.
+  """
+  def fetch(arr, idx) do
+    {:ok, get(arr, idx)}
+  end
+
+  @doc """
+  Access behavior `get/3` callback
+  """
+  def get(arr, idx, value) do
+    if size(arr) < idx do
+      get(arr, idx)
+    else
+      value
+    end
   end
 
+  @doc """
+  Access behavior `get_and_update/3` callback
+  """
   def get_and_update(arr, idx, fun) do
-    {get, update} = fun.(Array.get(arr, idx))
-    {get, Array.set(arr, idx, update)}
+    value = get(arr, idx)
+    case fun.(value) do
+      {get, update} -> {get, set(arr, idx, update)}
+      :pop          -> {value, set(arr, idx, nil)}
+    end
+  end
+
+  @doc """
+  Access behavior `pop/2` callback
+  """
+  def pop(arr, idx) do
+    if size(arr) < idx do
+      {get(arr, idx), set(arr, idx, nil)}
+    else
+      {nil, arr}
+    end
   end
 end
 
@@ -341,6 +371,15 @@ defimpl Enumerable, for: Array do
   def reduce(%Array{content: c}, acc, fun) do
     Enumerable.reduce(:array.to_list(c), acc, fun)
   end
+
+  def slice(arr) do
+    slice_fun = fn (start, length) ->
+      for i <- start..(start + length - 1) do
+        Array.get(arr, i)
+      end
+    end
+    {:ok, Array.size(arr), slice_fun}
+  end
 end
 
 defimpl Collectable, for: Array do

mix.exs

@@ -2,30 +2,18 @@ defmodule Array.Mixfile do
   use Mix.Project
 
   def project do
-    [app: :array,
-     version: "1.0.1",
-     elixir: ">= 1.0.0",
+    [app: :elixir_array,
+     version: "2.1.0",
+     elixir: ">= 1.11.1",
      description: "An elixir wrapper library for Erlang's array.",
-     package: package,
-     deps: deps]
+     package: package(),
+     deps: deps()]
   end
 
-  # Configuration for the OTP application
-  #
-  # Type `mix help compile.app` for more information
   def application do
     [applications: [:logger]]
   end
 
-  # Dependencies can be Hex packages:
-  #
-  #   {:mydep, "~> 0.3.0"}
-  #
-  # Or git/path repositories:
-  #
-  #   {:mydep, git: "https://github.com/elixir-lang/mydep.git", tag: "0.1.0"}
-  #
-  # Type `mix help deps` for more examples and options
   defp deps do
     [{:earmark, ">= 0.0.0", only: :dev},
      {:ex_doc, "~> 0.6", only: :dev}]

test/array_test.exs

@@ -87,7 +87,7 @@ defmodule ArrayTest do
   test "fix" do
     a = Array.new()
     a = Array.set(a, 100, 0)
-    
+
     a = Array.fix(a)
     assert_raise ArgumentError, fn ->
       Array.set(a, 101, 0)
@@ -405,7 +405,7 @@ defmodule ArrayTest do
   test "to_erlang_array" do
     a = Array.from_list([1,2,3])
     ea = Array.to_erlang_array(a)
-    
+
     assert :array.is_array(ea)
     assert 3 == :array.size(ea)
     assert 1 == :array.get(0, ea)
@@ -454,6 +454,14 @@ defmodule ArrayTest do
     assert 6 == sum
   end
 
+  test "Enumerable.slice" do
+    slice = Enum.slice(Array.from_list([1,2,3,4,5]), 1, 2)
+    assert [2,3] == slice
+
+    slice = Enum.slice(Array.from_list([1,2,3,4,5]), 3, 1)
+    assert [4] == slice
+  end
+
   test "Collectable.into" do
     a = Enum.into([1,2,3], Array.new())
     assert Array.is_array(a)