Add Matching Brackets exercise

config.json

@@ -202,6 +202,14 @@
         "prerequisites": [],
         "difficulty": 8
       },
+      {
+        "slug": "matching-brackets",
+        "name": "Matching Brackets",
+        "uuid": "cc2a9d38-4d01-479a-a7d1-f1a5662cbc3e",
+        "practices": [],
+        "prerequisites": [],
+        "difficulty": 8
+      },
       {
         "slug": "pascals-triangle",
         "name": "Pascal's Triangle",

exercises/practice/matching-brackets/.docs/instructions.md

@@ -0,0 +1,5 @@
+# Instructions
+
+Given a string containing brackets `[]`, braces `{}`, parentheses `()`, or any combination thereof, verify that any and all pairs are matched and nested correctly.
+Any other characters should be ignored.
+For example, `"{what is (42)}?"` is balanced and `"[text}"` is not.

exercises/practice/matching-brackets/.docs/introduction.md

@@ -0,0 +1,8 @@
+# Introduction
+
+You're given the opportunity to write software for the Bracketeer™, an ancient but powerful mainframe.
+The software that runs on it is written in a proprietary language.
+Much of its syntax is familiar, but you notice _lots_ of brackets, braces and parentheses.
+Despite the Bracketeer™ being powerful, it lacks flexibility.
+If the source code has any unbalanced brackets, braces or parentheses, the Bracketeer™ crashes and must be rebooted.
+To avoid such a scenario, you start writing code that can verify that brackets, braces, and parentheses are balanced before attempting to run it on the Bracketeer™.

exercises/practice/matching-brackets/.meta/config.json

@@ -0,0 +1,21 @@
+{
+  "authors": [
+    "Steffan153"
+  ],
+  "files": {
+    "solution": [
+      "matching-brackets.sql"
+    ],
+    "test": [
+      "matching-brackets_test.sql"
+    ],
+    "example": [
+      ".meta/example.sql"
+    ],
+    "editor": [
+      "data.csv"
+    ]
+  },
+  "blurb": "Make sure the brackets and braces all match.",
+  "source": "Ginna Baker"
+}

exercises/practice/matching-brackets/.meta/example.sql

@@ -0,0 +1,31 @@
+ALTER TABLE "matching-brackets"
+ADD brackets TEXT DEFAULT '';
+
+PRAGMA recursive_triggers = ON;
+
+CREATE TRIGGER IF NOT EXISTS update_backets
+    AFTER UPDATE
+    ON "matching-brackets"
+    WHEN NEW.brackets != OLD.brackets
+BEGIN
+    UPDATE "matching-brackets"
+    SET brackets = REPLACE(REPLACE(REPLACE(brackets, '()', ''), '[]', ''), '{}', '')
+    WHERE brackets = NEW.brackets;
+END;
+
+UPDATE "matching-brackets"
+SET brackets = (
+    WITH cnt(n) AS (
+        SELECT 1
+        UNION ALL
+        SELECT n + 1 FROM cnt WHERE n <= LENGTH(input)
+    )
+
+    -- clean the input to only have ()[]{} characters
+    SELECT group_concat(SUBSTR(input, n, 1), '')
+    FROM cnt
+    WHERE '()[]{}' LIKE ('%' || SUBSTR(input, n, 1) || '%')
+);
+
+UPDATE "matching-brackets"
+SET result = (brackets = '');

exercises/practice/matching-brackets/.meta/tests.toml

@@ -0,0 +1,70 @@
+# 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.
+
+[81ec11da-38dd-442a-bcf9-3de7754609a5]
+description = "paired square brackets"
+
+[287f0167-ac60-4b64-8452-a0aa8f4e5238]
+description = "empty string"
+
+[6c3615a3-df01-4130-a731-8ef5f5d78dac]
+description = "unpaired brackets"
+
+[9d414171-9b98-4cac-a4e5-941039a97a77]
+description = "wrong ordered brackets"
+
+[f0f97c94-a149-4736-bc61-f2c5148ffb85]
+description = "wrong closing bracket"
+
+[754468e0-4696-4582-a30e-534d47d69756]
+description = "paired with whitespace"
+
+[ba84f6ee-8164-434a-9c3e-b02c7f8e8545]
+description = "partially paired brackets"
+
+[3c86c897-5ff3-4a2b-ad9b-47ac3a30651d]
+description = "simple nested brackets"
+
+[2d137f2c-a19e-4993-9830-83967a2d4726]
+description = "several paired brackets"
+
+[2e1f7b56-c137-4c92-9781-958638885a44]
+description = "paired and nested brackets"
+
+[84f6233b-e0f7-4077-8966-8085d295c19b]
+description = "unopened closing brackets"
+
+[9b18c67d-7595-4982-b2c5-4cb949745d49]
+description = "unpaired and nested brackets"
+
+[a0205e34-c2ac-49e6-a88a-899508d7d68e]
+description = "paired and wrong nested brackets"
+
+[1d5c093f-fc84-41fb-8c2a-e052f9581602]
+description = "paired and wrong nested brackets but innermost are correct"
+
+[ef47c21b-bcfd-4998-844c-7ad5daad90a8]
+description = "paired and incomplete brackets"
+
+[a4675a40-a8be-4fc2-bc47-2a282ce6edbe]
+description = "too many closing brackets"
+
+[a345a753-d889-4b7e-99ae-34ac85910d1a]
+description = "early unexpected brackets"
+
+[21f81d61-1608-465a-b850-baa44c5def83]
+description = "early mismatched brackets"
+
+[99255f93-261b-4435-a352-02bdecc9bdf2]
+description = "math expression"
+
+[8e357d79-f302-469a-8515-2561877256a1]
+description = "complex latex expression"

exercises/practice/matching-brackets/create_fixture.sql

@@ -0,0 +1,8 @@
+DROP TABLE IF EXISTS "matching-brackets";
+CREATE TABLE "matching-brackets" (
+    "input" TEXT,
+    "result" BOOLEAN
+);
+
+.mode csv
+.import ./data.csv matching-brackets

exercises/practice/matching-brackets/data.csv

@@ -0,0 +1,20 @@
+"[]",
+"",
+"[[",
+"}{",
+"{]",
+"{ }",
+"{[])",
+"{[]}",
+"{}[]",
+"([{}({}[])])",
+"{[)][]}",
+"([{])",
+"[({]})",
+"[({}])",
+"{}[",
+"[]]",
+")()",
+"{)()",
+"(((185 + 223.85) * 15) - 543)/2",
+"\left(\begin{array}{cc} \frac{1}{3} & x\\ \mathrm{e}^{x} &... x^2 \end{array}\right)",

exercises/practice/matching-brackets/matching-brackets.sql

@@ -0,0 +1,2 @@
+-- Schema: CREATE TABLE "matching-brackets" ("input" TEXT "result" BOOLEAN);
+-- Task: update the matching-brackets table and set the result based on the input field.

exercises/practice/matching-brackets/matching-brackets_test.sql

@@ -0,0 +1,35 @@
+-- Setup test table and read in student solution:
+.read ./test_setup.sql
+
+-- Test cases:
+INSERT INTO tests (name, uuid, input, expected)
+    VALUES
+        ('paired square brackets', '81ec11da-38dd-442a-bcf9-3de7754609a5', '[]', 1),
+        ('empty string', '287f0167-ac60-4b64-8452-a0aa8f4e5238', '', 1),
+        ('unpaired brackets', '6c3615a3-df01-4130-a731-8ef5f5d78dac', '[[', 0),
+        ('wrong ordered brackets', '9d414171-9b98-4cac-a4e5-941039a97a77', '}{', 0),
+        ('wrong closing bracket', 'f0f97c94-a149-4736-bc61-f2c5148ffb85', '{]', 0),
+        ('paired with whitespace', '754468e0-4696-4582-a30e-534d47d69756', '{ }', 1),
+        ('partially paired brackets', 'ba84f6ee-8164-434a-9c3e-b02c7f8e8545', '{[])', 0),
+        ('simple nested brackets', '3c86c897-5ff3-4a2b-ad9b-47ac3a30651d', '{[]}', 1),
+        ('several paired brackets', '2d137f2c-a19e-4993-9830-83967a2d4726', '{}[]', 1),
+        ('paired and nested brackets', '2e1f7b56-c137-4c92-9781-958638885a44', '([{}({}[])])', 1),
+        ('unopened closing brackets', '84f6233b-e0f7-4077-8966-8085d295c19b', '{[)][]}', 0),
+        ('unpaired and nested brackets', '9b18c67d-7595-4982-b2c5-4cb949745d49', '([{])', 0),
+        ('paired and wrong nested brackets', 'a0205e34-c2ac-49e6-a88a-899508d7d68e', '[({]})', 0),
+        ('paired and wrong nested brackets but innermost are correct', '1d5c093f-fc84-41fb-8c2a-e052f9581602', '[({}])', 0),
+        ('paired and incomplete brackets', 'ef47c21b-bcfd-4998-844c-7ad5daad90a8', '{}[', 0),
+        ('too many closing brackets', 'a4675a40-a8be-4fc2-bc47-2a282ce6edbe', '[]]', 0),
+        ('early unexpected brackets', 'a345a753-d889-4b7e-99ae-34ac85910d1a', ')()', 0),
+        ('early mismatched brackets', '21f81d61-1608-465a-b850-baa44c5def83', '{)()', 0),
+        ('math expression', '99255f93-261b-4435-a352-02bdecc9bdf2', '(((185 + 223.85) * 15) - 543)/2', 1),
+        ('complex latex expression', '8e357d79-f302-469a-8515-2561877256a1', '\left(\begin{array}{cc} \frac{1}{3} & x\\ \mathrm{e}^{x} &... x^2 \end{array}\right)', 1);
+
+-- Comparison of user input and the tests updates the status for each test:
+UPDATE tests
+SET status = 'pass'
+FROM (SELECT input, result FROM "matching-brackets") AS actual
+WHERE (actual.input, actual.result) = (tests.input, tests.expected);
+
+-- Write results and debug info:
+.read ./test_reporter.sql

exercises/practice/matching-brackets/test_reporter.sql

@@ -0,0 +1,16 @@
+-- Update message for failed tests to give helpful information:
+UPDATE tests
+SET message = 'Result for "' || tests.input || '" is ' || actual.result || ', but should be ' || tests.expected
+FROM (SELECT input, result FROM 'matching-brackets') AS actual
+WHERE actual.input = tests.input 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/matching-brackets/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 ./matching-brackets.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
+    input TEXT NOT NULL,
+    expected BOOLEAN NOT NULL
+);