Add Erlang version

erlang/src/gilded_rose.app.src

@@ -0,0 +1 @@
+{application, gilded_rose, [{vsn, "0.1"}]}.

erlang/src/gilded_rose.erl

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+-module(gilded_rose).
+
+-include("gilded_rose.hrl").
+
+-export([
+  update_quality/1
+]).
+
+-spec update_quality([#item{}]) -> [#item{}].
+update_quality(Items) ->
+  lists:map(fun update_item/1, Items).
+
+-spec update_item(#item{}) -> #item{}.
+update_item(Item = #item{name = Name}) ->
+  Item1 = if
+    Name /= "Aged Brie" andalso Name /= "Backstage passes to a TAFKAL80ETC concert" ->
+      if
+        Item#item.quality > 0 ->
+          if
+            Name /= "Sulfuras, Hand of Ragnaros" ->
+              Item#item{quality = Item#item.quality - 1};
+            true ->
+              Item
+          end;
+        true ->
+          Item
+      end;
+    true ->
+      if
+        Item#item.quality < 50 ->
+          Item2 = Item#item{quality = Item#item.quality + 1},
+          if
+            Name == "Backstage passes to a TAFKAL80ETC concert" ->
+              Item3 = if
+                Item2#item.sell_in < 11 ->
+                  if
+                    Item2#item.quality < 50 ->
+                      Item2#item{quality = Item2#item.quality + 1};
+                    true -> Item2
+                  end;
+                true -> Item2
+              end,
+              if
+                Item3#item.sell_in < 6 ->
+                  if
+                    Item3#item.quality < 50 ->
+                      Item3#item{quality = Item3#item.quality + 1};
+                    true -> Item3
+                  end;
+                true -> Item3
+              end;
+            true -> Item2
+          end;
+        true -> Item
+      end
+  end,
+  Item4 = if
+    Name /= "Sulfuras, Hand of Ragnaros" ->
+      Item1#item{sell_in = Item1#item.sell_in - 1};
+    true -> Item1
+  end,
+  if
+    Item4#item.sell_in < 0 ->
+      if
+        Name /= "Aged Brie" ->
+          if
+            Name /= "Backstage passes to a TAFKAL80ETC concert" ->
+              if
+                Item4#item.quality > 0 ->
+                  if
+                    Name /= "Sulfuras, Hand of Ragnaros" ->
+                      Item4#item{quality = Item4#item.quality - 1};
+                    true -> Item4
+                  end;
+                true -> Item4
+              end;
+            true -> Item4#item{quality = Item4#item.quality - Item4#item.quality}
+          end;
+        true ->
+          if
+            Item4#item.quality < 50 ->
+              Item4#item{quality = Item4#item.quality + 1};
+            true -> Item4
+          end
+      end;
+    true -> Item4
+  end.