Add Roman Numerals exercise

config.json

@@ -218,6 +218,14 @@
         "prerequisites": [],
         "difficulty": 8
       },
+      {
+        "slug": "roman-numerals",
+        "name": "Roman Numerals",
+        "uuid": "f109325a-2bbb-46d7-a7ed-fe8484509985",
+        "practices": [],
+        "prerequisites": [],
+        "difficulty": 8
+      },
       {
         "slug": "etl",
         "name": "ETL",

exercises/practice/roman-numerals/.docs/instructions.append.md

@@ -0,0 +1,9 @@
+# SQLite specific instructions
+
+This exercise requires you set the `result` column of the `roman-numerals` table to the correct value based on the number found in the `number` column.
+
+## Table Schema
+
+```sql
+CREATE TABLE "roman-numerals" ("number" INT, "result" TEXT);
+```

exercises/practice/roman-numerals/.docs/instructions.md

@@ -0,0 +1,12 @@
+# Introduction
+
+Your task is to convert a number from Arabic numerals to Roman numerals.
+
+For this exercise, we are only concerned about traditional Roman numerals, in which the largest number is MMMCMXCIX (or 3,999).
+
+~~~~exercism/note
+There are lots of different ways to convert between Arabic and Roman numerals.
+We recommend taking a naive approach first to familiarise yourself with the concept of Roman numerals and then search for more efficient methods.
+
+Make sure to check out our Deep Dive video at the end to explore the different approaches you can take!
+~~~~

exercises/practice/roman-numerals/.docs/introduction.md

@@ -0,0 +1,59 @@
+# Description
+
+Today, most people in the world use Arabic numerals (0–9).
+But if you travelled back two thousand years, you'd find that most Europeans were using Roman numerals instead.
+
+To write a Roman numeral we use the following Latin letters, each of which has a value:
+
+| M    | D   | C   | L   | X   | V   | I   |
+| ---- | --- | --- | --- | --- | --- | --- |
+| 1000 | 500 | 100 | 50  | 10  | 5   | 1   |
+
+A Roman numeral is a sequence of these letters, and its value is the sum of the letters' values.
+For example, `XVIII` has the value 18 (`10 + 5 + 1 + 1 + 1 = 18`).
+
+There's one rule that makes things trickier though, and that's that **the same letter cannot be used more than three times in succession**.
+That means that we can't express numbers such as 4 with the seemingly natural `IIII`.
+Instead, for those numbers, we use a subtraction method between two letters.
+So we think of `4` not as `1 + 1 + 1 + 1` but instead as `5 - 1`.
+And slightly confusingly to our modern thinking, we write the smaller number first.
+This applies only in the following cases: 4 (`IV`), 9 (`IX`), 40 (`XL`), 90 (`XC`), 400 (`CD`) and 900 (`CM`).
+
+Order matters in Roman numerals!
+Letters (and the special compounds above) must be ordered by decreasing value from left to right.
+
+Here are some examples:
+
+```text
+ 105 => CV
+---- => --
+ 100 => C
++  5 =>  V
+```
+
+```text
+ 106 => CVI
+---- => --
+ 100 => C
++  5 =>  V
++  1 =>   I
+```
+
+```text
+ 104 => CIV
+---- => ---
+ 100 => C
++  4 =>  IV
+```
+
+And a final more complex example:
+
+```text
+ 1996 => MCMXCVI
+----- => -------
+ 1000 => M
++ 900 =>  CM
++  90 =>    XC
++   5 =>      V
++   1 =>       I
+```

exercises/practice/roman-numerals/.meta/config.json

@@ -0,0 +1,22 @@
+{
+  "authors": [
+    "Steffan153"
+  ],
+  "files": {
+    "solution": [
+      "roman-numerals.sql"
+    ],
+    "test": [
+      "roman-numerals_test.sql"
+    ],
+    "example": [
+      ".meta/example.sql"
+    ],
+    "editor": [
+      "data.csv"
+    ]
+  },
+  "blurb": "Convert modern Arabic numbers into Roman numerals.",
+  "source": "The Roman Numeral Kata",
+  "source_url": "https://codingdojo.org/kata/RomanNumerals/"
+}

exercises/practice/roman-numerals/.meta/example.sql

@@ -0,0 +1,35 @@
+ALTER TABLE "roman-numerals"
+ADD temp_num TEXT DEFAULT '';
+
+PRAGMA recursive_triggers = ON;
+
+CREATE TRIGGER IF NOT EXISTS update_roman_numerals
+    AFTER UPDATE
+    ON "roman-numerals"
+    WHEN LENGTH(NEW.temp_num) > 0
+BEGIN
+    UPDATE "roman-numerals"
+    SET result =
+        -- we encode the roman numerals in base 10
+        -- to add a digit, we translate IVXLC => XLCDM (multiply by ten)
+        -- and then add the digit at the end
+
+        REPLACE(REPLACE(REPLACE(REPLACE(REPLACE(result, 'C', 'M'), 'L', 'D'), 'X', 'C'), 'V', 'L'), 'I', 'X') ||
+        CASE SUBSTR(temp_num, 1, 1)
+        WHEN '0' THEN ''
+        WHEN '1' THEN 'I'
+        WHEN '2' THEN 'II'
+        WHEN '3' THEN 'III'
+        WHEN '4' THEN 'IV'
+        WHEN '5' THEN 'V'
+        WHEN '6' THEN 'VI'
+        WHEN '7' THEN 'VII'
+        WHEN '8' THEN 'VIII'
+        WHEN '9' THEN 'IX'
+        END,
+        temp_num = SUBSTR(temp_num, 2)
+    WHERE temp_num = NEW.temp_num;
+END;
+
+UPDATE "roman-numerals"
+SET temp_num = number || '';

exercises/practice/roman-numerals/.meta/tests.toml

@@ -0,0 +1,91 @@
+# 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.
+
+[19828a3a-fbf7-4661-8ddd-cbaeee0e2178]
+description = "1 is I"
+
+[f088f064-2d35-4476-9a41-f576da3f7b03]
+description = "2 is II"
+
+[b374a79c-3bea-43e6-8db8-1286f79c7106]
+description = "3 is III"
+
+[05a0a1d4-a140-4db1-82e8-fcc21fdb49bb]
+description = "4 is IV"
+
+[57c0f9ad-5024-46ab-975d-de18c430b290]
+description = "5 is V"
+
+[20a2b47f-e57f-4797-a541-0b3825d7f249]
+description = "6 is VI"
+
+[ff3fb08c-4917-4aab-9f4e-d663491d083d]
+description = "9 is IX"
+
+[6d1d82d5-bf3e-48af-9139-87d7165ed509]
+description = "16 is XVI"
+
+[2bda64ca-7d28-4c56-b08d-16ce65716cf6]
+description = "27 is XXVII"
+
+[a1f812ef-84da-4e02-b4f0-89c907d0962c]
+description = "48 is XLVIII"
+
+[607ead62-23d6-4c11-a396-ef821e2e5f75]
+description = "49 is XLIX"
+
+[d5b283d4-455d-4e68-aacf-add6c4b51915]
+description = "59 is LIX"
+
+[4465ffd5-34dc-44f3-ada5-56f5007b6dad]
+description = "66 is LXVI"
+
+[46b46e5b-24da-4180-bfe2-2ef30b39d0d0]
+description = "93 is XCIII"
+
+[30494be1-9afb-4f84-9d71-db9df18b55e3]
+description = "141 is CXLI"
+
+[267f0207-3c55-459a-b81d-67cec7a46ed9]
+description = "163 is CLXIII"
+
+[902ad132-0b4d-40e3-8597-ba5ed611dd8d]
+description = "166 is CLXVI"
+
+[cdb06885-4485-4d71-8bfb-c9d0f496b404]
+description = "402 is CDII"
+
+[6b71841d-13b2-46b4-ba97-dec28133ea80]
+description = "575 is DLXXV"
+
+[dacb84b9-ea1c-4a61-acbb-ce6b36674906]
+description = "666 is DCLXVI"
+
+[432de891-7fd6-4748-a7f6-156082eeca2f]
+description = "911 is CMXI"
+
+[e6de6d24-f668-41c0-88d7-889c0254d173]
+description = "1024 is MXXIV"
+
+[efbe1d6a-9f98-4eb5-82bc-72753e3ac328]
+description = "1666 is MDCLXVI"
+
+[bb550038-d4eb-4be2-a9ce-f21961ac3bc6]
+description = "3000 is MMM"
+
+[3bc4b41c-c2e6-49d9-9142-420691504336]
+description = "3001 is MMMI"
+
+[2f89cad7-73f6-4d1b-857b-0ef531f68b7e]
+description = "3888 is MMMDCCCLXXXVIII"
+
+[4e18e96b-5fbb-43df-a91b-9cb511fe0856]
+description = "3999 is MMMCMXCIX"

exercises/practice/roman-numerals/create_fixture.sql

@@ -0,0 +1,8 @@
+DROP TABLE IF EXISTS "roman-numerals";
+CREATE TABLE "roman-numerals" (
+    "number" INT,
+    "result" TEXT
+);
+
+.mode csv
+.import ./data.csv roman-numerals

exercises/practice/roman-numerals/data.csv

@@ -0,0 +1,27 @@
+1,""
+2,""
+3,""
+4,""
+5,""
+6,""
+9,""
+16,""
+27,""
+48,""
+49,""
+59,""
+66,""
+93,""
+141,""
+163,""
+166,""
+402,""
+575,""
+666,""
+911,""
+1024,""
+1666,""
+3000,""
+3001,""
+3888,""
+3999,""

exercises/practice/roman-numerals/roman-numerals.sql

@@ -0,0 +1,2 @@
+-- Schema: CREATE TABLE "roman-numerals" ("number" INT, "result" TEXT);
+-- Task: update the roman-numerals table and set the result based on the number.

exercises/practice/roman-numerals/roman-numerals_test.sql

@@ -0,0 +1,44 @@
+-- Setup test table and read in student solution:
+.read ./test_setup.sql
+
+-- Test cases:
+INSERT INTO tests (name, uuid,
+                    number, expected)
+    VALUES
+        ('1 is I', '19828a3a-fbf7-4661-8ddd-cbaeee0e2178', 1, 'I'),
+        ('2 is II', 'f088f064-2d35-4476-9a41-f576da3f7b03', 2, 'II'),
+        ('3 is III', 'b374a79c-3bea-43e6-8db8-1286f79c7106', 3, 'III'),
+        ('4 is IV', '05a0a1d4-a140-4db1-82e8-fcc21fdb49bb', 4, 'IV'),
+        ('5 is V', '57c0f9ad-5024-46ab-975d-de18c430b290', 5, 'V'),
+        ('6 is VI', '20a2b47f-e57f-4797-a541-0b3825d7f249', 6, 'VI'),
+        ('9 is IX', 'ff3fb08c-4917-4aab-9f4e-d663491d083d', 9, 'IX'),
+        ('16 is XVI', '6d1d82d5-bf3e-48af-9139-87d7165ed509', 16, 'XVI'),
+        ('27 is XXVII', '2bda64ca-7d28-4c56-b08d-16ce65716cf6', 27, 'XXVII'),
+        ('48 is XLVIII', 'a1f812ef-84da-4e02-b4f0-89c907d0962c', 48, 'XLVIII'),
+        ('49 is XLIX', '607ead62-23d6-4c11-a396-ef821e2e5f75', 49, 'XLIX'),
+        ('59 is LIX', 'd5b283d4-455d-4e68-aacf-add6c4b51915', 59, 'LIX'),
+        ('66 is LXVI', '4465ffd5-34dc-44f3-ada5-56f5007b6dad', 66, 'LXVI'),
+        ('93 is XCIII', '46b46e5b-24da-4180-bfe2-2ef30b39d0d0', 93, 'XCIII'),
+        ('141 is CXLI', '30494be1-9afb-4f84-9d71-db9df18b55e3', 141, 'CXLI'),
+        ('163 is CLXIII', '267f0207-3c55-459a-b81d-67cec7a46ed9', 163, 'CLXIII'),
+        ('166 is CLXVI', '902ad132-0b4d-40e3-8597-ba5ed611dd8d', 166, 'CLXVI'),
+        ('402 is CDII', 'cdb06885-4485-4d71-8bfb-c9d0f496b404', 402, 'CDII'),
+        ('575 is DLXXV', '6b71841d-13b2-46b4-ba97-dec28133ea80', 575, 'DLXXV'),
+        ('666 is DCLXVI', 'dacb84b9-ea1c-4a61-acbb-ce6b36674906', 666, 'DCLXVI'),
+        ('911 is CMXI', '432de891-7fd6-4748-a7f6-156082eeca2f', 911, 'CMXI'),
+        ('1024 is MXXIV', 'e6de6d24-f668-41c0-88d7-889c0254d173', 1024, 'MXXIV'),
+        ('1666 is MDCLXVI', 'efbe1d6a-9f98-4eb5-82bc-72753e3ac328', 1666, 'MDCLXVI'),
+        ('3000 is MMM', 'bb550038-d4eb-4be2-a9ce-f21961ac3bc6', 3000, 'MMM'),
+        ('3001 is MMMI', '3bc4b41c-c2e6-49d9-9142-420691504336', 3001, 'MMMI'),
+        ('3888 is MMMDCCCLXXXVIII', '2f89cad7-73f6-4d1b-857b-0ef531f68b7e', 3888, 'MMMDCCCLXXXVIII'),
+        ('3999 is MMMCMXCIX', '4e18e96b-5fbb-43df-a91b-9cb511fe0856', 3999, 'MMMCMXCIX');
+
+-- Comparison of user input and the tests updates the status for each test:
+UPDATE tests
+SET status = 'pass'
+FROM (SELECT number, result FROM "roman-numerals") AS actual
+WHERE (actual.number, actual.result) = (tests.number, tests.expected);
+
+-- Write results and debug info:
+.read ./test_reporter.sql
+

exercises/practice/roman-numerals/test_reporter.sql

@@ -0,0 +1,16 @@
+-- Update message for failed tests to give helpful information:
+UPDATE tests
+SET message = 'Result for ' || actual.number || ' is "' || actual.result || '", but should be: "' || tests.expected || '"'
+FROM (SELECT number, result FROM "roman-numerals") AS actual
+WHERE actual.number = tests.number AND tests.status = 'fail';
+
+-- Save results to ./output.json (needed by the online test-runner)
+.mode json
+.once './output.json'
+SELECT name, status, message, output, test_code, task_id
+FROM tests;
+
+-- Display test results in readable form for the student:
+.mode table
+SELECT name, status, message
+FROM tests;

exercises/practice/roman-numerals/test_setup.sql

@@ -0,0 +1,25 @@
+-- Create database:
+.read ./create_fixture.sql
+
+-- Read user student solution and save any output as markdown in user_output.md:
+.mode markdown
+.output user_output.md
+.read ./roman-numerals.sql
+.output
+
+-- Create a clean testing environment:
+DROP TABLE IF EXISTS tests;
+CREATE TABLE IF NOT EXISTS tests (
+    -- uuid and name (description) are taken from the test.toml file
+    uuid TEXT PRIMARY KEY,
+    name TEXT NOT NULL,
+    -- The following section is needed by the online test-runner
+    status TEXT DEFAULT 'fail',
+    message TEXT,
+    output TEXT,
+    test_code TEXT,
+    task_id INTEGER DEFAULT NULL,
+    -- Here are columns for the actual tests
+    number INT NOT NULL,
+    expected TEXT NOT NULL
+);