Add new practice exercise: word-count

config.json

@@ -354,6 +354,14 @@
         "prerequisites": [],
         "difficulty": 8
       },
+      {
+        "slug": "word-count",
+        "name": "Word Count",
+        "uuid": "67ef66f1-4a18-42ba-86ca-59c296487c0d",
+        "practices": [],
+        "prerequisites": [],
+        "difficulty": 8
+      },
       {
         "slug": "yacht",
         "name": "Yacht",

exercises/practice/word-count/.docs/instructions.append.md

@@ -0,0 +1,25 @@
+# SQLite-specific instructions
+
+The **result** column should contain JSON-encoded object of objects, each word as key and count as integer.
+
+For example, consider the sentence above: `"That's the password: 'PASSWORD 123'!", cried the Special Agent.\nSo I fled.`
+The **result** for this input should be:
+
+```json
+{"123":1,"agent":1,"cried":1,"fled":1,"i":1,"password":2,"so":1,"special":1,"that's":1,"the":2}
+```
+
+## Table Schema
+
+```sql
+CREATE TABLE "word-count" (
+    sentence TEXT NOT NULL,
+    result   TEXT               -- json object
+);
+```
+
+## JSON documentation
+
+[JSON Functions And Operators][json-docs]
+
+[json-docs]: https://www.sqlite.org/json1.html

exercises/practice/word-count/.docs/instructions.md

@@ -0,0 +1,47 @@
+# Instructions
+
+Your task is to count how many times each word occurs in a subtitle of a drama.
+
+The subtitles from these dramas use only ASCII characters.
+
+The characters often speak in casual English, using contractions like _they're_ or _it's_.
+Though these contractions come from two words (e.g. _we are_), the contraction (_we're_) is considered a single word.
+
+Words can be separated by any form of punctuation (e.g. ":", "!", or "?") or whitespace (e.g. "\t", "\n", or " ").
+The only punctuation that does not separate words is the apostrophe in contractions.
+
+Numbers are considered words.
+If the subtitles say _It costs 100 dollars._ then _100_ will be its own word.
+
+Words are case insensitive.
+For example, the word _you_ occurs three times in the following sentence:
+
+> You come back, you hear me? DO YOU HEAR ME?
+
+The ordering of the word counts in the results doesn't matter.
+
+Here's an example that incorporates several of the elements discussed above:
+
+- simple words
+- contractions
+- numbers
+- case insensitive words
+- punctuation (including apostrophes) to separate words
+- different forms of whitespace to separate words
+
+`"That's the password: 'PASSWORD 123'!", cried the Special Agent.\nSo I fled.`
+
+The mapping for this subtitle would be:
+
+```text
+123: 1
+agent: 1
+cried: 1
+fled: 1
+i: 1
+password: 2
+so: 1
+special: 1
+that's: 1
+the: 2
+```

exercises/practice/word-count/.docs/introduction.md

@@ -0,0 +1,8 @@
+# Introduction
+
+You teach English as a foreign language to high school students.
+
+You've decided to base your entire curriculum on TV shows.
+You need to analyze which words are used, and how often they're repeated.
+
+This will let you choose the simplest shows to start with, and to gradually increase the difficulty as time passes.

exercises/practice/word-count/.meta/config.json

@@ -0,0 +1,18 @@
+{
+  "authors": [
+    "jimmytty"
+  ],
+  "files": {
+    "solution": [
+      "word-count.sql"
+    ],
+    "test": [
+      "word-count_test.sql"
+    ],
+    "example": [
+      ".meta/example.sql"
+    ]
+  },
+  "blurb": "Given a phrase, count the occurrences of each word in that phrase.",
+  "source": "This is a classic toy problem, but we were reminded of it by seeing it in the Go Tour."
+}

exercises/practice/word-count/.meta/example.sql

@@ -0,0 +1,32 @@
+UPDATE "word-count"
+   SET result = (
+     WITH RECURSIVE to_words (string, word) AS (
+       VALUES((
+         WITH RECURSIVE mark_sep (string, letter) AS (
+           VALUES(LOWER(sentence), '')
+           UNION ALL
+           SELECT SUBSTRING(string, 2), CASE
+             WHEN GLOB('[0-9a-z'']', SUBSTRING(string, 1, 1))
+             THEN SUBSTRING(string, 1, 1)
+             ELSE CHAR(10)
+           END
+             FROM mark_sep
+            WHERE string <> ''
+         ) SELECT GROUP_CONCAT(letter, '') || CHAR(10) AS string FROM mark_sep
+       ), NULL)
+       UNION ALL
+       SELECT SUBSTRING(
+         string, INSTR(string, CHAR(10)) + 1),
+         TRIM(SUBSTRING(string, 1, INSTR(string, CHAR(10)) - 1), ''''
+       )
+         FROM to_words
+        WHERE string <> ''
+     )
+     SELECT JSON_GROUP_OBJECT(word, count)
+       FROM (
+         SELECT word, COUNT(*) count
+           FROM to_words
+          WHERE word NOT IN ('', CHAR(10))
+          GROUP BY word
+       )
+   );

exercises/practice/word-count/.meta/tests.toml

@@ -0,0 +1,57 @@
+# 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.
+
+[61559d5f-2cad-48fb-af53-d3973a9ee9ef]
+description = "count one word"
+
+[5abd53a3-1aed-43a4-a15a-29f88c09cbbd]
+description = "count one of each word"
+
+[2a3091e5-952e-4099-9fac-8f85d9655c0e]
+description = "multiple occurrences of a word"
+
+[e81877ae-d4da-4af4-931c-d923cd621ca6]
+description = "handles cramped lists"
+
+[7349f682-9707-47c0-a9af-be56e1e7ff30]
+description = "handles expanded lists"
+
+[a514a0f2-8589-4279-8892-887f76a14c82]
+description = "ignore punctuation"
+
+[d2e5cee6-d2ec-497b-bdc9-3ebe092ce55e]
+description = "include numbers"
+
+[dac6bc6a-21ae-4954-945d-d7f716392dbf]
+description = "normalize case"
+
+[4185a902-bdb0-4074-864c-f416e42a0f19]
+description = "with apostrophes"
+include = false
+
+[4ff6c7d7-fcfc-43ef-b8e7-34ff1837a2d3]
+description = "with apostrophes"
+reimplements = "4185a902-bdb0-4074-864c-f416e42a0f19"
+
+[be72af2b-8afe-4337-b151-b297202e4a7b]
+description = "with quotations"
+
+[8d6815fe-8a51-4a65-96f9-2fb3f6dc6ed6]
+description = "substrings from the beginning"
+
+[c5f4ef26-f3f7-4725-b314-855c04fb4c13]
+description = "multiple spaces not detected as a word"
+
+[50176e8a-fe8e-4f4c-b6b6-aa9cf8f20360]
+description = "alternating word separators not detected as a word"
+
+[6d00f1db-901c-4bec-9829-d20eb3044557]
+description = "quotation for word with apostrophe"

exercises/practice/word-count/create_fixture.sql

@@ -0,0 +1,11 @@
+DROP TABLE IF EXISTS "word-count";
+CREATE TABLE "word-count" (
+    sentence TEXT NOT NULL,
+    result   TEXT               -- json object
+);
+
+.mode csv
+.import ./data.csv "word-count"
+
+UPDATE "word-count" SET sentence = REPLACE(sentence, '\n', CHAR(10));
+UPDATE "word-count" SET result = NULL;

exercises/practice/word-count/create_test_table.sql

@@ -0,0 +1,34 @@
+DROP TABLE IF EXISTS tests;
+CREATE TABLE IF NOT EXISTS tests (
+    -- uuid and description are taken from the test.toml file
+    uuid TEXT PRIMARY KEY,
+    description 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
+    sentence TEXT NOT NULL,
+    expected TEXT NOT NULL      -- json object
+);
+
+INSERT INTO tests (uuid, description, sentence, expected)
+    VALUES
+        ('61559d5f-2cad-48fb-af53-d3973a9ee9ef', 'count one word', 'word', '{"word":1}'),
+        ('5abd53a3-1aed-43a4-a15a-29f88c09cbbd', 'count one of each word', 'one of each', '{"one":1,"of":1,"each":1}'),
+        ('2a3091e5-952e-4099-9fac-8f85d9655c0e', 'multiple occurrences of a word', 'one fish two fish red fish blue fish', '{"one":1,"fish":4,"two":1,"red":1,"blue":1}'),
+        ('e81877ae-d4da-4af4-931c-d923cd621ca6', 'handles cramped lists', 'one,two,three', '{"one":1,"two":1,"three":1}'),
+        ('7349f682-9707-47c0-a9af-be56e1e7ff30', 'handles expanded lists', 'one,\ntwo,\nthree', '{"one":1,"two":1,"three":1}'),
+        ('a514a0f2-8589-4279-8892-887f76a14c82', 'ignore punctuation', 'car: carpet as java: javascript!!&@$%^&', '{"car":1,"carpet":1,"as":1,"java":1,"javascript":1}'),
+        ('d2e5cee6-d2ec-497b-bdc9-3ebe092ce55e', 'include numbers', 'testing, 1, 2 testing', '{"testing":2,"1":1,"2":1}'),
+        ('dac6bc6a-21ae-4954-945d-d7f716392dbf', 'normalize case', 'go Go GO Stop stop', '{"go":3,"stop":2}'),
+        ('4ff6c7d7-fcfc-43ef-b8e7-34ff1837a2d3', 'with apostrophes', '''First: don''t laugh. Then: don''t cry. You''re getting it.''', '{"first":1,"don''t":2,"laugh":1,"then":1,"cry":1,"you''re":1,"getting":1,"it":1}'),
+        ('be72af2b-8afe-4337-b151-b297202e4a7b', 'with quotations', 'Joe can''t tell between ''large'' and large.', '{"joe":1,"can''t":1,"tell":1,"between":1,"large":2,"and":1}'),
+        ('8d6815fe-8a51-4a65-96f9-2fb3f6dc6ed6', 'substrings from the beginning', 'Joe can''t tell between app, apple and a.', '{"joe":1,"can''t":1,"tell":1,"between":1,"app":1,"apple":1,"and":1,"a":1}'),
+        ('c5f4ef26-f3f7-4725-b314-855c04fb4c13', 'multiple spaces not detected as a word', ' multiple   whitespaces', '{"multiple":1,"whitespaces":1}'),
+        ('50176e8a-fe8e-4f4c-b6b6-aa9cf8f20360', 'alternating word separators not detected as a word', ',\n,one,\n ,two \n ''three''', '{"one":1,"two":1,"three":1}'),
+        ('6d00f1db-901c-4bec-9829-d20eb3044557', 'quotation for word with apostrophe', 'can, can''t, ''can''t''', '{"can":1,"can''t":2}');
+
+UPDATE tests SET sentence = REPLACE(sentence, '\n', CHAR(10));

exercises/practice/word-count/data.csv

@@ -0,0 +1,15 @@
+"word",""
+"one of each",""
+"one fish two fish red fish blue fish",""
+"one,two,three",""
+"one,\ntwo,\nthree",""
+"car: carpet as java: javascript!!&@$%^&",""
+"testing, 1, 2 testing",""
+"go Go GO Stop stop",""
+"First: don't laugh. Then: don't cry.",""
+"'First: don't laugh. Then: don't cry. You're getting it.'",""
+"Joe can't tell between 'large' and large.",""
+"Joe can't tell between app, apple and a.",""
+" multiple   whitespaces",""
+",\n,one,\n ,two \n 'three'",""
+"can, can't, 'can't'",""

exercises/practice/word-count/word-count.sql

@@ -0,0 +1,9 @@
+-- Schema:
+-- CREATE TABLE "word-count" (
+--     sentence TEXT NOT NULL,
+--     result   TEXT               -- json object
+-- );
+--
+-- Task: update the word-count table and set the result based on sentence.
+--       * the result column should contain JSON-encoded object of objects,
+--         each word as key and count as integer.

exercises/practice/word-count/word-count_test.sql

@@ -0,0 +1,40 @@
+-- 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 ./word-count.sql
+.output
+
+-- Create a clean testing environment:
+.read ./create_test_table.sql
+
+-- Comparison of user input and the tests updates the status for each test:
+UPDATE tests
+SET status = 'pass'
+FROM (SELECT sentence, result FROM "word-count") AS actual
+WHERE actual.sentence = tests.sentence AND JSON_PATCH(actual.result, tests.expected) = actual.result AND JSON_PATCH(tests.expected, actual.result) = tests.expected;
+
+-- Update message for failed tests to give helpful information:
+UPDATE tests
+SET message = (
+    'Result for "'
+    || tests.sentence
+    || '"'
+    || ' is <' || COALESCE(actual.result, 'NULL')
+    || '> but should be <' || tests.expected || '>'
+)
+FROM (SELECT sentence, result FROM "word-count") AS actual
+WHERE actual.sentence = tests.sentence AND tests.status = 'fail';
+
+-- Save results to ./output.json (needed by the online test-runner)
+.mode json
+.once './output.json'
+SELECT description, status, message, output, test_code, task_id
+FROM tests;
+
+-- Display test results in readable form for the student:
+.mode table
+SELECT description, status, message
+FROM tests;