LFE (Lisp Flavoured Erlang) version.

delete beam file.

Initial version for LFE.

delete original lfe file.

lfe/src/gilded-rose.app.src

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+{application, 'gilded-rose', [
+    {description, "A run-ready LFE script"},
+    {vsn, "0.1"},
+    {registered, []},
+    {applications, [
+        kernel,
+        stdlib
+    ]},
+    {env,[]},
+    {modules, []},
+
+    {licenses, ["Apache 2.0"]},
+    {links, []}
+ ]}.

lfe/src/gilded-rose.lfe

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+;; Hi and welcome to team Gilded Rose. As you know, we are a small inn
+;; with a prime location in a prominent city ran by a friendly
+;; innkeeper named Allison. We also buy and sell only the finest goods.
+;; Unfortunately, our goods are constantly degrading in (item-quality item) as they
+;; approach their sell by date. We have a system in place that updates
+;; our inventory for us. It was developed by a no-nonsense type named
+;; Leeroy, who has moved on to new adventures. Your task is to add the
+;; new feature to our system so that we can begin selling a new
+;; category of items.
+
+;; First an introduction to our system:
+;; All items have a SellIn value which denotes the number of days we have to sell the item
+;; All items have a Quality value which denotes how valuable the item is
+;; At the end of each day our system lowers both values for every item
+;; Pretty simple, right? Well this is where it gets interesting:
+;; Once the sell by date has passed, Quality degrades twice as fast
+;; The Quality of an item is never negative
+;; "Aged Brie" actually increases in Quality the older it gets
+;; The Quality of an item is never more than 50
+;; "Sulfuras", being a legendary item, never has to be sold or decreases in Quality
+;; "Backstage passes", like aged brie, increases in Quality as it's
+;;   SellIn value approaches; Quality increases by 2 when there are 10
+;;   days or less and by 3 when there are 5 days or less but Quality
+;;   drops to 0 after the concert
+
+;; We have recently signed a supplier of conjured items. This requires an update to our system:
+;; "Conjured" items degrade in Quality twice as fast as normal items
+;; Feel free to make any changes to the UpdateQuality method and add
+;; any new code as long as everything still works correctly. However,
+;; do not alter the Item class or Items property as those belong to the
+;; goblin in the corner who will insta-rage and one-shot you as he
+;; doesn't believe in shared code ownership (you can make the
+;; UpdateQuality method and Items property static if you like, we'll
+;; cover for you).
+;; Just for clarification, an item can never have its Quality increase
+;; above 50, however "Sulfuras" is a legendary item and as such its
+;; Quality is 80 and it never alters.
+
+;; https://github.com/emilybache/GildedRose-Refactoring-Kata
+
+;; LFE version by Manfred Bergmann, 2022
+
+;;; ================================================================
+;;; Code
+
+(defmodule gilded-rose
+  (export all))
+
+;;; Item
+
+(defrecord item
+  name sellin quality)
+
+;; for external use by 'import'
+(defun make-item (name sellin quality)
+  (make-item name name sellin sellin quality quality))
+(defun item-name (item)
+  (item-name item))
+
+;; update-quality
+
+(defun update-quality (items)
+  (lists:map #'update-item/1 items))
+
+(defun update-item (item)
+  (let* ((item (if (and (not (string:equal (item-name item)
+                                           "Aged Brie"))
+                        (not (string:equal (item-name item)
+                                           "Backstage passes to a TAFKAL80ETC concert")))
+                 (if (> (item-quality item) 0)
+                   (if (not (string:equal (item-name item)
+                                          "Sulfuras, Hand of Ragnaros"))
+                     (set-item-quality item (- (item-quality item) 1))
+                     item)
+                   item)
+                 (if (< (item-quality item) 50)
+                   (set-item-quality item (+ (item-quality item) 1))
+                   (if (string:equal (item-name item)
+                                     "Backstage passes to a TAFKAL80ETC concert")
+                     (if (< (item-sellin item) 11)
+                       (if (< (item-quality item) 50)
+                         (set-item-quality item (+ (item-quality item) 1))
+                         item)
+                       item)
+                     (if (< (item-sellin item) 6)
+                       (if (< (item-quality item) 50)
+                         (set-item-quality item (+ (item-quality item) 1))
+                         item)
+                       item)))))
+         (item (if (not (string:equal (item-name item)
+                                      "Sulfuras, Hand of Ragnaros"))
+                 (set-item-sellin item (- (item-sellin item) 1))
+                 item)))
+    (if (< (item-sellin item) 0)
+      (if (not (string:equal (item-name item)
+                             "Aged Brie"))
+        (if (not (string:equal (item-name item)
+                               "Backstage passes to a TAFKAL80ETC concert"))
+          (if (> (item-quality item) 0)
+            (if (not (string:equal (item-name item)
+                                   "Sulfuras, Hand of Ragnaros"))
+              (set-item-quality item (- (item-quality item) 1))
+              item)
+            item)
+          (set-item-quality item (- (item-quality item) (item-quality item))))
+        (if (< (item-quality item) 50)
+          (set-item-quality item (+ (item-quality item) 1))
+          item))
+      item)))
+
+;;; Example
+
+(defun print-item (item)
+  (io:format "~s ~b ~b~n" (list (item-name item) (item-sellin item) (item-quality item))))
+
+(defun print-day (day items)
+  (io:format "-------- day ~b --------~n" (list day))
+  (io:format "name, sellin, quality~n")
+  (lists:foreach #'print-item/1 items)
+  (io:format "~n"))
+
+(defrecord gilded-rose items)
+
+(defun run-gilded-rose (days)
+  (io:format "OMGHAI!~n")
+  (let ((items (list (make-item name "+5 Dexterity Vest" sellin 10 quality 20)
+                     (make-item name "Aged Brie" sellin 2 quality 0)
+                     (make-item name "Elixir of the Mongoose" sellin 5 quality 7)
+                     (make-item name "Sulfuras, Hand of Ragnaros" sellin 0 quality 80)
+                     (make-item name "Sulfuras, Hand of Ragnaros" sellin -1 quality 80)
+                     (make-item name "Backstage passes to a TAFKAL80ETC concert" sellin 15 quality 20)
+                     (make-item name "Backstage passes to a TAFKAL80ETC concert" sellin 10 quality 49)
+                     (make-item name "Backstage passes to a TAFKAL80ETC concert" sellin 5 quality 49)
+                     ;; this conjured item does not work properly yet
+                     (make-item name "Conjured Mana Cake" sellin 3 quality 6))))
+
+    (lists:foldl (lambda (day gr)
+                   (print-day day (gilded-rose-items gr))
+                   (make-gilded-rose items (update-quality (gilded-rose-items gr))))
+                 (make-gilded-rose items items)
+                 (lists:seq 0 days))))
+