From 5993c42ad7fe9301dd5103a9b6d7692a7302124c Mon Sep 17 00:00:00 2001
From: Marten/Qqwy <w-m@wmcode.nl>
Date: Mon, 6 Sep 2021 09:46:37 +0200
Subject: [PATCH] Use Arrays.Protocol.empty in implementation of other
 functions.

---
 lib/arrays.ex                              |  2 +-
 lib/arrays/implementations/erlang_array.ex |  8 +-------
 lib/arrays/implementations/map_array.ex    | 24 ++++++++--------------
 3 files changed, 11 insertions(+), 23 deletions(-)

diff --git a/lib/arrays.ex b/lib/arrays.ex
index 6faa136..e7f7055 100644
--- a/lib/arrays.ex
+++ b/lib/arrays.ex
@@ -299,7 +299,7 @@ contents = quote do
       )
 
     options = Keyword.delete(options, :implementation)
-    impl_module.empty(options)
+    Module.concat(Arrays.Protocol, impl_module).empty(options)
   end
 
   defp default_array_implementation() do
diff --git a/lib/arrays/implementations/erlang_array.ex b/lib/arrays/implementations/erlang_array.ex
index f05c402..88e8d0d 100644
--- a/lib/arrays/implementations/erlang_array.ex
+++ b/lib/arrays/implementations/erlang_array.ex
@@ -18,12 +18,6 @@ defmodule Arrays.Implementations.ErlangArray do
 
   defstruct contents: :array.new([default: nil])
 
-  @impl Arrays.Behaviour
-  def empty(options) do
-    contents = :array.new([default: nil] ++ options)
-    %ErlangArray{contents: contents}
-  end
-
   @doc """
   Create an `%ErlangArray{}`-struct from an `:array`-record.
 
@@ -276,7 +270,7 @@ defmodule Arrays.Implementations.ErlangArray do
 
     @impl true
     def slice(array = %ErlangArray{}, start, amount) do
-      @for.build_slice(array, start, amount, @for.empty(default: :array.default(array.contents)))
+      @for.build_slice(array, start, amount, empty(default: :array.default(array.contents)))
     end
 
     @impl true
diff --git a/lib/arrays/implementations/map_array.ex b/lib/arrays/implementations/map_array.ex
index a7e3aa1..a401a2c 100644
--- a/lib/arrays/implementations/map_array.ex
+++ b/lib/arrays/implementations/map_array.ex
@@ -9,18 +9,6 @@ defmodule Arrays.Implementations.MapArray do
 
   defstruct contents: %{}, default: nil
 
-  @impl Arrays.Behaviour
-  def empty(options) do
-    default = Keyword.get(options, :default, nil)
-    size = Keyword.get(options, :size, 0)
-    %MapArray{contents: construct(default, size), default: default}
-  end
-
-  defp construct(_default, 0), do: %{}
-
-  defp construct(default, size) do
-    Enum.into(0..(size - 1), %{}, &{&1, default})
-  end
 
   if Code.ensure_loaded?(FunLand.Mappable) do
     Module.eval_quoted(__MODULE__,
@@ -209,7 +197,7 @@ defmodule Arrays.Implementations.MapArray do
 
     @impl true
     def resize(%MapArray{default: default}, 0) do
-      MapArray.empty(default: default)
+      empty(default: default)
     end
 
     def resize(array = %MapArray{contents: contents}, size) when map_size(contents) == size do
@@ -250,14 +238,20 @@ defmodule Arrays.Implementations.MapArray do
 
     @impl true
     def slice(array = %MapArray{}, start, amount) do
-      @for.build_slice(array, start, amount, @for.empty(default: array.default))
+      @for.build_slice(array, start, amount, empty(default: array.default))
     end
 
     @impl true
     def empty(options) when is_list(options) do
       default = Keyword.get(options, :default, nil)
       size = Keyword.get(options, :size, 0)
-      %MapArray{contents: MapArray.construct(default, size), default: default}
+      %MapArray{contents: construct(default, size), default: default}
+    end
+
+    defp construct(_default, 0), do: %{}
+
+    defp construct(default, size) do
+      Enum.into(0..(size - 1), %{}, &{&1, default})
     end
   end
 end