From 9a6d9713678184657953e5a986f7211b82534742 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Andr=C3=A1s=20B=20Nagy?=
 <20251272+BNAndras@users.noreply.github.com>
Date: Wed, 25 Oct 2023 22:34:01 -0700
Subject: [PATCH 1/2] Add clock exercise

---
 config.json                                   |   8 +
 .../practice/clock/.docs/instructions.md      |   7 +
 exercises/practice/clock/.meta/config.json    |  18 ++
 exercises/practice/clock/.meta/example.rkt    |  46 ++++
 exercises/practice/clock/.meta/tests.toml     | 166 ++++++++++++
 exercises/practice/clock/clock-test.rkt       | 236 ++++++++++++++++++
 exercises/practice/clock/clock.rkt            |  19 ++
 7 files changed, 500 insertions(+)
 create mode 100644 exercises/practice/clock/.docs/instructions.md
 create mode 100644 exercises/practice/clock/.meta/config.json
 create mode 100644 exercises/practice/clock/.meta/example.rkt
 create mode 100644 exercises/practice/clock/.meta/tests.toml
 create mode 100644 exercises/practice/clock/clock-test.rkt
 create mode 100644 exercises/practice/clock/clock.rkt

diff --git a/config.json b/config.json
index 28eba6ab..b9514112 100644
--- a/config.json
+++ b/config.json
@@ -259,6 +259,14 @@
         "prerequisites": [],
         "difficulty": 1
       },
+      {
+        "slug": "clock",
+        "name": "Clock",
+        "uuid": "5618c228-fa15-4450-9a61-b41369d7de06",
+        "practices": [],
+        "prerequisites": [],
+        "difficulty": 3
+      },
       {
         "slug": "etl",
         "name": "ETL",
diff --git a/exercises/practice/clock/.docs/instructions.md b/exercises/practice/clock/.docs/instructions.md
new file mode 100644
index 00000000..a1efc789
--- /dev/null
+++ b/exercises/practice/clock/.docs/instructions.md
@@ -0,0 +1,7 @@
+# Instructions
+
+Implement a clock that handles times without dates.
+
+You should be able to add and subtract minutes to it.
+
+Two clocks that represent the same time should be equal to each other.
diff --git a/exercises/practice/clock/.meta/config.json b/exercises/practice/clock/.meta/config.json
new file mode 100644
index 00000000..b26a9fe1
--- /dev/null
+++ b/exercises/practice/clock/.meta/config.json
@@ -0,0 +1,18 @@
+{
+  "authors": [
+    "BNAndras"
+  ],
+  "files": {
+    "solution": [
+      "clock.rkt"
+    ],
+    "test": [
+      "clock-test.rkt"
+    ],
+    "example": [
+      ".meta/example.rkt"
+    ]
+  },
+  "blurb": "Implement a clock that handles times without dates.",
+  "source": "Pairing session with Erin Drummond"
+}
diff --git a/exercises/practice/clock/.meta/example.rkt b/exercises/practice/clock/.meta/example.rkt
new file mode 100644
index 00000000..e907066e
--- /dev/null
+++ b/exercises/practice/clock/.meta/example.rkt
@@ -0,0 +1,46 @@
+#lang racket
+
+(provide (struct-out clock)
+         add
+         subtract
+         clock->string)
+
+(struct clock (hours minutes)
+  #:transparent
+  #:methods
+  gen:equal+hash
+  [(define (equal-proc self other rec)
+     (define normalized-self (normalize-clock self))
+     (define normalized-other (normalize-clock other))
+     (and (rec (clock-hours normalized-self)
+            (clock-hours normalized-other))
+          (rec (clock-minutes normalized-self)
+            (clock-minutes normalized-other))))
+   (define (hash-proc self rec)
+     (define normalized (normalize-clock self))
+     (+ (* (rec (clock-hours normalized) 60)
+           (rec (clock-minutes normalized)))))
+   (define (hash2-proc self rec)
+     (define normalized (normalize-clock self))
+     (+ (rec (clock-hours normalized))
+        (/ (rec (clock-minutes normalized) 60))))])
+
+(define (normalize-clock c)
+  (let* ([total-minutes (modulo (+ (* (clock-hours c) 60) (clock-minutes c)) 1440)]
+         [new-hours (modulo (quotient total-minutes 60) 24)]
+         [new-minutes (modulo (- total-minutes (* new-hours 60)) 60)])
+    (clock new-hours new-minutes)))
+
+(define (clock->string c)
+  (define normalized (normalize-clock c))
+  (~a (~a (clock-hours normalized) #:width 2 #:align 'right #:pad-string "0")
+      ":"
+      (~a (clock-minutes normalized) #:width 2 #:align 'right #:pad-string "0")))
+
+(define (add c minutes)
+  (clock (clock-hours c)
+         (+ (clock-minutes c) minutes)))
+
+(define (subtract c minutes)
+  (clock (clock-hours c)
+         (- (clock-minutes c) minutes)))
diff --git a/exercises/practice/clock/.meta/tests.toml b/exercises/practice/clock/.meta/tests.toml
new file mode 100644
index 00000000..712c87bc
--- /dev/null
+++ b/exercises/practice/clock/.meta/tests.toml
@@ -0,0 +1,166 @@
+# This is an auto-generated file.
+#
+# Regenerating this file via `configlet sync` will:
+# - Recreate every `description` key/value pair
+# - Recreate every `reimplements` key/value pair, where they exist in problem-specifications
+# - Remove any `include = true` key/value pair (an omitted `include` key implies inclusion)
+# - Preserve any other key/value pair
+#
+# As user-added comments (using the # character) will be removed when this file
+# is regenerated, comments can be added via a `comment` key.
+
+[a577bacc-106b-496e-9792-b3083ea8705e]
+description = "Create a new clock with an initial time -> on the hour"
+
+[b5d0c360-3b88-489b-8e84-68a1c7a4fa23]
+description = "Create a new clock with an initial time -> past the hour"
+
+[473223f4-65f3-46ff-a9f7-7663c7e59440]
+description = "Create a new clock with an initial time -> midnight is zero hours"
+
+[ca95d24a-5924-447d-9a96-b91c8334725c]
+description = "Create a new clock with an initial time -> hour rolls over"
+
+[f3826de0-0925-4d69-8ac8-89aea7e52b78]
+description = "Create a new clock with an initial time -> hour rolls over continuously"
+
+[a02f7edf-dfd4-4b11-b21a-86de3cc6a95c]
+description = "Create a new clock with an initial time -> sixty minutes is next hour"
+
+[8f520df6-b816-444d-b90f-8a477789beb5]
+description = "Create a new clock with an initial time -> minutes roll over"
+
+[c75c091b-47ac-4655-8d40-643767fc4eed]
+description = "Create a new clock with an initial time -> minutes roll over continuously"
+
+[06343ecb-cf39-419d-a3f5-dcbae0cc4c57]
+description = "Create a new clock with an initial time -> hour and minutes roll over"
+
+[be60810e-f5d9-4b58-9351-a9d1e90e660c]
+description = "Create a new clock with an initial time -> hour and minutes roll over continuously"
+
+[1689107b-0b5c-4bea-aad3-65ec9859368a]
+description = "Create a new clock with an initial time -> hour and minutes roll over to exactly midnight"
+
+[d3088ee8-91b7-4446-9e9d-5e2ad6219d91]
+description = "Create a new clock with an initial time -> negative hour"
+
+[77ef6921-f120-4d29-bade-80d54aa43b54]
+description = "Create a new clock with an initial time -> negative hour rolls over"
+
+[359294b5-972f-4546-bb9a-a85559065234]
+description = "Create a new clock with an initial time -> negative hour rolls over continuously"
+
+[509db8b7-ac19-47cc-bd3a-a9d2f30b03c0]
+description = "Create a new clock with an initial time -> negative minutes"
+
+[5d6bb225-130f-4084-84fd-9e0df8996f2a]
+description = "Create a new clock with an initial time -> negative minutes roll over"
+
+[d483ceef-b520-4f0c-b94a-8d2d58cf0484]
+description = "Create a new clock with an initial time -> negative minutes roll over continuously"
+
+[1cd19447-19c6-44bf-9d04-9f8305ccb9ea]
+description = "Create a new clock with an initial time -> negative sixty minutes is previous hour"
+
+[9d3053aa-4f47-4afc-bd45-d67a72cef4dc]
+description = "Create a new clock with an initial time -> negative hour and minutes both roll over"
+
+[51d41fcf-491e-4ca0-9cae-2aa4f0163ad4]
+description = "Create a new clock with an initial time -> negative hour and minutes both roll over continuously"
+
+[d098e723-ad29-4ef9-997a-2693c4c9d89a]
+description = "Add minutes -> add minutes"
+
+[b6ec8f38-e53e-4b22-92a7-60dab1f485f4]
+description = "Add minutes -> add no minutes"
+
+[efd349dd-0785-453e-9ff8-d7452a8e7269]
+description = "Add minutes -> add to next hour"
+
+[749890f7-aba9-4702-acce-87becf4ef9fe]
+description = "Add minutes -> add more than one hour"
+
+[da63e4c1-1584-46e3-8d18-c9dc802c1713]
+description = "Add minutes -> add more than two hours with carry"
+
+[be167a32-3d33-4cec-a8bc-accd47ddbb71]
+description = "Add minutes -> add across midnight"
+
+[6672541e-cdae-46e4-8be7-a820cc3be2a8]
+description = "Add minutes -> add more than one day (1500 min = 25 hrs)"
+
+[1918050d-c79b-4cb7-b707-b607e2745c7e]
+description = "Add minutes -> add more than two days"
+
+[37336cac-5ede-43a5-9026-d426cbe40354]
+description = "Subtract minutes -> subtract minutes"
+
+[0aafa4d0-3b5f-4b12-b3af-e3a9e09c047b]
+description = "Subtract minutes -> subtract to previous hour"
+
+[9b4e809c-612f-4b15-aae0-1df0acb801b9]
+description = "Subtract minutes -> subtract more than an hour"
+
+[8b04bb6a-3d33-4e6c-8de9-f5de6d2c70d6]
+description = "Subtract minutes -> subtract across midnight"
+
+[07c3bbf7-ce4d-4658-86e8-4a77b7a5ccd9]
+description = "Subtract minutes -> subtract more than two hours"
+
+[90ac8a1b-761c-4342-9c9c-cdc3ed5db097]
+description = "Subtract minutes -> subtract more than two hours with borrow"
+
+[2149f985-7136-44ad-9b29-ec023a97a2b7]
+description = "Subtract minutes -> subtract more than one day (1500 min = 25 hrs)"
+
+[ba11dbf0-ac27-4acb-ada9-3b853ec08c97]
+description = "Subtract minutes -> subtract more than two days"
+
+[f2fdad51-499f-4c9b-a791-b28c9282e311]
+description = "Compare two clocks for equality -> clocks with same time"
+
+[5d409d4b-f862-4960-901e-ec430160b768]
+description = "Compare two clocks for equality -> clocks a minute apart"
+
+[a6045fcf-2b52-4a47-8bb2-ef10a064cba5]
+description = "Compare two clocks for equality -> clocks an hour apart"
+
+[66b12758-0be5-448b-a13c-6a44bce83527]
+description = "Compare two clocks for equality -> clocks with hour overflow"
+
+[2b19960c-212e-4a71-9aac-c581592f8111]
+description = "Compare two clocks for equality -> clocks with hour overflow by several days"
+
+[6f8c6541-afac-4a92-b0c2-b10d4e50269f]
+description = "Compare two clocks for equality -> clocks with negative hour"
+
+[bb9d5a68-e324-4bf5-a75e-0e9b1f97a90d]
+description = "Compare two clocks for equality -> clocks with negative hour that wraps"
+
+[56c0326d-565b-4d19-a26f-63b3205778b7]
+description = "Compare two clocks for equality -> clocks with negative hour that wraps multiple times"
+
+[c90b9de8-ddff-4ffe-9858-da44a40fdbc2]
+description = "Compare two clocks for equality -> clocks with minute overflow"
+
+[533a3dc5-59a7-491b-b728-a7a34fe325de]
+description = "Compare two clocks for equality -> clocks with minute overflow by several days"
+
+[fff49e15-f7b7-4692-a204-0f6052d62636]
+description = "Compare two clocks for equality -> clocks with negative minute"
+
+[605c65bb-21bd-43eb-8f04-878edf508366]
+description = "Compare two clocks for equality -> clocks with negative minute that wraps"
+
+[b87e64ed-212a-4335-91fd-56da8421d077]
+description = "Compare two clocks for equality -> clocks with negative minute that wraps multiple times"
+
+[822fbf26-1f3b-4b13-b9bf-c914816b53dd]
+description = "Compare two clocks for equality -> clocks with negative hours and minutes"
+
+[e787bccd-cf58-4a1d-841c-ff80eaaccfaa]
+description = "Compare two clocks for equality -> clocks with negative hours and minutes that wrap"
+
+[96969ca8-875a-48a1-86ae-257a528c44f5]
+description = "Compare two clocks for equality -> full clock and zeroed clock"
diff --git a/exercises/practice/clock/clock-test.rkt b/exercises/practice/clock/clock-test.rkt
new file mode 100644
index 00000000..9fb7df62
--- /dev/null
+++ b/exercises/practice/clock/clock-test.rkt
@@ -0,0 +1,236 @@
+#lang racket/base
+
+(require "clock.rkt")
+
+(module+ test
+  (require rackunit rackunit/text-ui)
+
+  (define suite
+    (test-suite
+     "clock tests"
+
+     (test-equal? "Create a new clock with an initial time - on the hour"
+                  (clock->string (clock 8 0))
+                  "08:00")
+
+     (test-equal? "Create a new clock with an initial time - past the hour"
+                  (clock->string (clock 11 9))
+                  "11:09")
+
+     (test-equal? "Create a new clock with an initial time - midnight is zero hours"
+                  (clock->string (clock 24 0))
+                  "00:00")
+
+     (test-equal? "Create a new clock with an initial time - hour rolls over"
+                  (clock->string (clock 25 0))
+                  "01:00")
+
+     (test-equal? "Create a new clock with an initial time - hour rolls over continuously"
+                  (clock->string (clock 100 0))
+                  "04:00")
+
+     (test-equal? "Create a new clock with an initial time - sixty minutes is next hour"
+                  (clock->string (clock 1 60))
+                  "02:00")
+
+     (test-equal? "Create a new clock with an initial time - minutes roll over"
+                  (clock->string (clock 0 160))
+                  "02:40")
+
+     (test-equal? "Create a new clock with an initial time - minutes roll over continuously"
+                  (clock->string (clock 0 1723))
+                  "04:43")
+
+     (test-equal? "Create a new clock with an initial time - hour and minutes roll over"
+                  (clock->string (clock 25 160))
+                  "03:40")
+
+     (test-equal? "Create a new clock with an initial time - hour and minutes roll over continuously"
+                  (clock->string (clock 201 3001))
+                  "11:01")
+
+     (test-equal? "Create a new clock with an initial time - hour and minutes roll over to exactly midnight"
+                  (clock->string (clock 72 8640))
+                  "00:00")
+
+     (test-equal? "Create a new clock with an initial time - negative hour"
+                  (clock->string (clock -1 15))
+                  "23:15")
+
+     (test-equal? "Create a new clock with an initial time - negative hour rolls over"
+                  (clock->string (clock -25 0))
+                  "23:00")
+
+     (test-equal? "Create a new clock with an initial time - negative hour rolls over continuously"
+                  (clock->string (clock -91 0))
+                  "05:00")
+
+     (test-equal? "Create a new clock with an initial time - negative minutes"
+                  (clock->string (clock 1 -40))
+                  "00:20")
+
+     (test-equal? "Create a new clock with an initial time - negative minutes roll over"
+                  (clock->string (clock 1 -160))
+                  "22:20")
+
+     (test-equal? "Create a new clock with an initial time - negative minutes roll over continuously"
+                  (clock->string (clock 1 -4820))
+                  "16:40")
+
+     (test-equal? "Create a new clock with an initial time - negative sixty minutes is previous hour"
+                  (clock->string (clock 2 -60))
+                  "01:00")
+
+     (test-equal? "Create a new clock with an initial time - negative hour and minutes both roll over"
+                  (clock->string (clock -25 -160))
+                  "20:20")
+
+     (test-equal? "Create a new clock with an initial time - negative hour and minutes both roll over continuously"
+                  (clock->string (clock -121 -5810))
+                  "22:10")
+
+     (test-equal? "Add minutes - add minutes"
+                  (clock->string (add (clock 10 0)
+                                      3))
+                  "10:03")
+
+     (test-equal? "Add minutes - add no minutes"
+                  (clock->string (add (clock 6 41)
+                                      0))
+                  "06:41")
+
+     (test-equal? "Add minutes - add to next hour"
+                  (clock->string (add (clock 0 45)
+                                      40))
+                  "01:25")
+
+     (test-equal? "Add minutes - add more than one hour"
+                  (clock->string (add (clock 10 0)
+                                      61))
+                  "11:01")
+
+     (test-equal? "Add minutes - add more than two hours with carry"
+                  (clock->string (add (clock 0 45)
+                                      160))
+                  "03:25")
+
+     (test-equal? "Add minutes - add across midnight"
+                  (clock->string (add (clock 23 59)
+                                      2))
+                  "00:01")
+
+     (test-equal? "Add minutes - add more than one day (1500 min = 25 hrs)"
+                  (clock->string (add (clock 5 32)
+                                      1500))
+                  "06:32")
+
+     (test-equal? "Add minutes - add more than two days"
+                  (clock->string (add (clock 1 1)
+                                      3500))
+                  "11:21")
+
+     (test-equal? "Subtract minutes - subtract minutes"
+                  (clock->string (subtract (clock 10 3)
+                                           3))
+                  "10:00")
+
+     (test-equal? "Subtract minutes - subtract to previous hour"
+                  (clock->string (subtract (clock 10 3)
+                                           30))
+                  "09:33")
+
+     (test-equal? "Subtract minutes - subtract more than an hour"
+                  (clock->string (subtract (clock 10 3)
+                                           70))
+                  "08:53")
+
+     (test-equal? "Subtract minutes - subtract across midnight"
+                  (clock->string (subtract (clock 0 3)
+                                           4))
+                  "23:59")
+
+     (test-equal? "Subtract minutes - subtract more than two hours"
+                  (clock->string (subtract (clock 0 0)
+                                           160))
+                  "21:20")
+
+     (test-equal? "Subtract minutes - subtract more than two hours with borrow"
+                  (clock->string (subtract (clock 6 15)
+                                           160))
+                  "03:35")
+
+     (test-equal? "Subtract minutes - subtract more than one day (1500 min = 25 hrs)"
+                  (clock->string (subtract (clock 5 32)
+                                           1500))
+                  "04:32")
+
+     (test-equal? "Subtract minutes - subtract more than two days"
+                  (clock->string (subtract (clock 2 20)
+                                           3000))
+                  "00:20")
+
+     (test-equal? "Compare two clocks for equality - clocks with same time"
+                  (clock 15 37)
+                  (clock 15 37))
+
+     (test-case "Compare two clocks for equality - clocks a minute apart"
+                (check-not-equal? (clock 15 36)
+                                  (clock 15 37)))
+
+     (test-case "Compare two clocks for equality - clocks an hour apart"
+                (check-not-equal? (clock 14 37)
+                                  (clock 15 37)))
+
+     (test-equal? "Compare two clocks for equality - clocks with hour overflow"
+                  (clock 10 37)
+                  (clock 34 37))
+
+     (test-equal? "Compare two clocks for equality - clocks with hour overflow by several days"
+                  (clock 3 11)
+                  (clock 99 11))
+
+     (test-equal? "Compare two clocks for equality - clocks with negative hour"
+                  (clock 22 40)
+                  (clock -2 40))
+
+     (test-equal? "Compare two clocks for equality - clocks with negative hour that wraps"
+                  (clock 17 3)
+                  (clock -31 3))
+
+     (test-equal? "Compare two clocks for equality - clocks with negative hour that wraps multiple times"
+                  (clock 13 49)
+                  (clock -83 49))
+
+     (test-equal? "Compare two clocks for equality - clocks with minute overflow"
+                  (clock 0 1)
+                  (clock 0 1441))
+
+     (test-equal? "Compare two clocks for equality - clocks with minute overflow by several days"
+                  (clock 2 2)
+                  (clock 2 4322))
+
+     (test-equal? "Compare two clocks for equality - clocks with negative minute"
+                  (clock 2 40)
+                  (clock 3 -20))
+
+     (test-equal? "Compare two clocks for equality - clocks with negative minute that wraps"
+                  (clock 4 10)
+                  (clock 5 -1490))
+
+     (test-equal? "Compare two clocks for equality - clocks with negative minute that wraps multiple times"
+                  (clock 6 15)
+                  (clock 6 -4305))
+
+     (test-equal? "Compare two clocks for equality - clocks with negative hours and minutes"
+                  (clock 7 32)
+                  (clock -12 -268))
+
+     (test-equal? "Compare two clocks for equality - clocks with negative hours and minutes that wrap"
+                  (clock 18 7)
+                  (clock -54 -11513))
+
+     (test-equal? "Compare two clocks for equality - full clock and zeroed clock"
+                  (clock 24 0)
+                  (clock 0 0))))
+
+  (run-tests suite))
diff --git a/exercises/practice/clock/clock.rkt b/exercises/practice/clock/clock.rkt
new file mode 100644
index 00000000..c6b6ac94
--- /dev/null
+++ b/exercises/practice/clock/clock.rkt
@@ -0,0 +1,19 @@
+#lang racket
+
+(provide (struct-out clock)
+          add
+          subtract
+          clock->string)
+
+(struct clock
+    ()) ; Add your implementation
+
+
+(define (clock->string c)
+  (error "Not implemented yet"))
+
+(define (add c minutes)
+  (error "Not implemented yet"))
+
+(define (subtract c minutes)
+  (error "Not implemented yet"))

From 99b9e7b9460d5eb63f92aec8e7bb56a66009e2d9 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Andr=C3=A1s=20B=20Nagy?=
 <20251272+BNAndras@users.noreply.github.com>
Date: Wed, 25 Oct 2023 22:48:20 -0700
Subject: [PATCH 2/2] Simplify stub

---
 exercises/practice/clock/clock.rkt | 12 +++++-------
 1 file changed, 5 insertions(+), 7 deletions(-)

diff --git a/exercises/practice/clock/clock.rkt b/exercises/practice/clock/clock.rkt
index c6b6ac94..1cce0782 100644
--- a/exercises/practice/clock/clock.rkt
+++ b/exercises/practice/clock/clock.rkt
@@ -1,13 +1,11 @@
 #lang racket
 
-(provide (struct-out clock)
-          add
-          subtract
-          clock->string)
-
-(struct clock
-    ()) ; Add your implementation
+(provide clock
+         add
+         subtract
+         clock->string)
 
+; We have provided stubs for add, subtract, and clock->string. The clock implementation is up to you.
 
 (define (clock->string c)
   (error "Not implemented yet"))