From bfa49b48b605b36f0b5b0c028fb4e376453e80e6 Mon Sep 17 00:00:00 2001
From: Dan Barber <github@danbarber.me>
Date: Tue, 13 Mar 2018 22:45:13 -0400
Subject: [PATCH] Make code clearer

---
 lib/chess/moves/pawn.ex | 29 +++++++++++++++--------------
 1 file changed, 15 insertions(+), 14 deletions(-)

diff --git a/lib/chess/moves/pawn.ex b/lib/chess/moves/pawn.ex
index 67bae47..dc375b0 100644
--- a/lib/chess/moves/pawn.ex
+++ b/lib/chess/moves/pawn.ex
@@ -3,28 +3,29 @@ defmodule Chess.Moves.Pawn do
 
   def moves(board, {file, rank}) do
     board["#{file},#{rank}"]
+    |> Map.get("colour")
     |> _moves(board, {file, rank})
   end
 
-  defp _moves(%{"colour" => "white"}, board, {file, rank}) do
+  defp _moves("white", board, {file, rank}) do
     cond do
-      obstruction?(board, {file, rank + 1}) -> []
-      rank == 1 -> [
-        {file, rank + 1} |
-        _moves(%{"colour" => "white"}, board, {file, rank + 1})
-      ]
-      true -> [{file, rank + 1}]
+      obstruction?(board, {file, rank + 1}) ->
+        []
+      rank == 1 ->
+        [{file, rank + 1} | _moves("white", board, {file, rank + 1})]
+      true ->
+        [{file, rank + 1}]
     end
   end
 
-  defp _moves(%{"colour" => "black"}, board, {file, rank}) do
+  defp _moves("black", board, {file, rank}) do
     cond do
-      obstruction?(board, {file, rank - 1}) -> []
-      rank == 6 -> [
-        {file, rank - 1} |
-        _moves(%{"colour" => "black"}, board, {file, rank - 1})
-      ]
-      true -> [{file, rank - 1}]
+      obstruction?(board, {file, rank - 1}) ->
+        []
+      rank == 6 ->
+        [{file, rank - 1} | _moves("black", board, {file, rank - 1})]
+      true ->
+        [{file, rank - 1}]
     end
   end