Add wordy practice exercise (#503)

Author: ryanplusplus

config.json

@@ -1042,6 +1042,14 @@
           "text_formatting"
         ]
       },
+      {
+        "slug": "wordy",
+        "name": "Wordy",
+        "uuid": "37165dd0-bb19-4606-acfb-2a382c8bb274",
+        "practices": [],
+        "prerequisites": [],
+        "difficulty": 4
+      },
       {
         "slug": "rational-numbers",
         "name": "Rational Numbers",

exercises/practice/wordy/.busted

@@ -0,0 +1,5 @@
+return {
+  default = {
+    ROOT = { '.' }
+  }
+}

exercises/practice/wordy/.docs/instructions.md

@@ -0,0 +1,59 @@
+# Instructions
+
+Parse and evaluate simple math word problems returning the answer as an integer.
+
+## Iteration 0 — Numbers
+
+Problems with no operations simply evaluate to the number given.
+
+> What is 5?
+
+Evaluates to 5.
+
+## Iteration 1 — Addition
+
+Add two numbers together.
+
+> What is 5 plus 13?
+
+Evaluates to 18.
+
+Handle large numbers and negative numbers.
+
+## Iteration 2 — Subtraction, Multiplication and Division
+
+Now, perform the other three operations.
+
+> What is 7 minus 5?
+
+2
+
+> What is 6 multiplied by 4?
+
+24
+
+> What is 25 divided by 5?
+
+5
+
+## Iteration 3 — Multiple Operations
+
+Handle a set of operations, in sequence.
+
+Since these are verbal word problems, evaluate the expression from left-to-right, _ignoring the typical order of operations._
+
+> What is 5 plus 13 plus 6?
+
+24
+
+> What is 3 plus 2 multiplied by 3?
+
+15 (i.e. not 9)
+
+## Iteration 4 — Errors
+
+The parser should reject:
+
+- Unsupported operations ("What is 52 cubed?")
+- Non-math questions ("Who is the President of the United States")
+- Word problems with invalid syntax ("What is 1 plus plus 2?")

exercises/practice/wordy/.meta/config.json

@@ -0,0 +1,17 @@
+{
+  "authors": ["ryanplusplus"],
+  "files": {
+    "solution": [
+      "wordy.lua"
+    ],
+    "test": [
+      "wordy_spec.lua"
+    ],
+    "example": [
+      ".meta/example.lua"
+    ]
+  },
+  "blurb": "Parse and evaluate simple math word problems returning the answer as an integer.",
+  "source": "Inspired by one of the generated questions in the Extreme Startup game.",
+  "source_url": "https://github.com/rchatley/extreme_startup"
+}

exercises/practice/wordy/.meta/example.lua

@@ -0,0 +1,31 @@
+local function answer(question)
+  local accumulator
+
+  local remaining = question:gsub('%s*(%D+)%s+([-%d]+)', function(operator, operand)
+    operand = assert(tonumber(operand))
+
+    if operator == 'What is' then
+      accumulator = operand
+    elseif operator == 'plus' then
+      accumulator = accumulator + operand
+    elseif operator == 'minus' then
+      accumulator = accumulator - operand
+    elseif operator == 'multiplied by' then
+      accumulator = accumulator * operand
+    elseif operator == 'divided by' then
+      accumulator = accumulator / operand
+    else
+      error('Invalid question')
+    end
+
+    return ''
+  end)
+
+  if remaining ~= '?' then
+    error('Invalid question')
+  end
+
+  return accumulator
+end
+
+return { answer = answer }

exercises/practice/wordy/.meta/tests.toml

@@ -0,0 +1,79 @@
+# 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.
+
+[88bf4b28-0de3-4883-93c7-db1b14aa806e]
+description = "just a number"
+
+[bb8c655c-cf42-4dfc-90e0-152fcfd8d4e0]
+description = "addition"
+
+[79e49e06-c5ae-40aa-a352-7a3a01f70015]
+description = "more addition"
+
+[b345dbe0-f733-44e1-863c-5ae3568f3803]
+description = "addition with negative numbers"
+
+[cd070f39-c4cc-45c4-97fb-1be5e5846f87]
+description = "large addition"
+
+[0d86474a-cd93-4649-a4fa-f6109a011191]
+description = "subtraction"
+
+[30bc8395-5500-4712-a0cf-1d788a529be5]
+description = "multiplication"
+
+[34c36b08-8605-4217-bb57-9a01472c427f]
+description = "division"
+
+[da6d2ce4-fb94-4d26-8f5f-b078adad0596]
+description = "multiple additions"
+
+[7fd74c50-9911-4597-be09-8de7f2fea2bb]
+description = "addition and subtraction"
+
+[b120ffd5-bad6-4e22-81c8-5512e8faf905]
+description = "multiple subtraction"
+
+[4f4a5749-ef0c-4f60-841f-abcfaf05d2ae]
+description = "subtraction then addition"
+
+[312d908c-f68f-42c9-aa75-961623cc033f]
+description = "multiple multiplication"
+
+[38e33587-8940-4cc1-bc28-bfd7e3966276]
+description = "addition and multiplication"
+
+[3c854f97-9311-46e8-b574-92b60d17d394]
+description = "multiple division"
+
+[3ad3e433-8af7-41ec-aa9b-97b42ab49357]
+description = "unknown operation"
+
+[8a7e85a8-9e7b-4d46-868f-6d759f4648f8]
+description = "Non math question"
+
+[42d78b5f-dbd7-4cdb-8b30-00f794bb24cf]
+description = "reject problem missing an operand"
+
+[c2c3cbfc-1a72-42f2-b597-246e617e66f5]
+description = "reject problem with no operands or operators"
+
+[4b3df66d-6ed5-4c95-a0a1-d38891fbdab6]
+description = "reject two operations in a row"
+
+[6abd7a50-75b4-4665-aa33-2030fd08bab1]
+description = "reject two numbers in a row"
+
+[10a56c22-e0aa-405f-b1d2-c642d9c4c9de]
+description = "reject postfix notation"
+
+[0035bc63-ac43-4bb5-ad6d-e8651b7d954e]
+description = "reject prefix notation"

exercises/practice/wordy/wordy.lua

@@ -0,0 +1,5 @@
+local function answer(question)
+
+end
+
+return { answer = answer }

exercises/practice/wordy/wordy_spec.lua

@@ -0,0 +1,111 @@
+local wordy = require('wordy')
+
+describe('wordy', function()
+  it('just a number', function()
+    assert.are.same(5, wordy.answer('What is 5?'))
+  end)
+
+  it('addition', function()
+    assert.are.same(2, wordy.answer('What is 1 plus 1?'))
+  end)
+
+  it('more addition', function()
+    assert.are.same(55, wordy.answer('What is 53 plus 2?'))
+  end)
+
+  it('addition with negative numbers', function()
+    assert.are.same(-11, wordy.answer('What is -1 plus -10?'))
+  end)
+
+  it('large addition', function()
+    assert.are.same(45801, wordy.answer('What is 123 plus 45678?'))
+  end)
+
+  it('subtraction', function()
+    assert.are.same(16, wordy.answer('What is 4 minus -12?'))
+  end)
+
+  it('multiplication', function()
+    assert.are.same(-75, wordy.answer('What is -3 multiplied by 25?'))
+  end)
+
+  it('division', function()
+    assert.are.same(-11, wordy.answer('What is 33 divided by -3?'))
+  end)
+
+  it('multiple additions', function()
+    assert.are.same(3, wordy.answer('What is 1 plus 1 plus 1?'))
+  end)
+
+  it('addition and subtraction', function()
+    assert.are.same(8, wordy.answer('What is 1 plus 5 minus -2?'))
+  end)
+
+  it('multiple subtraction', function()
+    assert.are.same(3, wordy.answer('What is 20 minus 4 minus 13?'))
+  end)
+
+  it('subtraction then addition', function()
+    assert.are.same(14, wordy.answer('What is 17 minus 6 plus 3?'))
+  end)
+
+  it('multiple multiplication', function()
+    assert.are.same(-12, wordy.answer('What is 2 multiplied by -2 multiplied by 3?'))
+  end)
+
+  it('addition and multiplication', function()
+    assert.are.same(-8, wordy.answer('What is -3 plus 7 multiplied by -2?'))
+  end)
+
+  it('multiple division', function()
+    assert.are.same(2, wordy.answer('What is -12 divided by 2 divided by -3?'))
+  end)
+
+  it('unknown operation', function()
+    assert.has_error(function()
+      wordy.answer('What is 52 cubed?')
+    end, 'Invalid question')
+  end)
+
+  it('Non math question', function()
+    assert.has_error(function()
+      wordy.answer('Who is the President of the United States?')
+    end, 'Invalid question')
+  end)
+
+  it('reject problem missing an operand', function()
+    assert.has_error(function()
+      wordy.answer('What is 1 plus?')
+    end, 'Invalid question')
+  end)
+
+  it('reject problem with no operands or operators', function()
+    assert.has_error(function()
+      wordy.answer('What is?')
+    end, 'Invalid question')
+  end)
+
+  it('reject two operations in a row', function()
+    assert.has_error(function()
+      wordy.answer('What is 1 plus plus 2?')
+    end, 'Invalid question')
+  end)
+
+  it('reject two numbers in a row', function()
+    assert.has_error(function()
+      wordy.answer('What is 1 plus 2 1?')
+    end, 'Invalid question')
+  end)
+
+  it('reject postfix notation', function()
+    assert.has_error(function()
+      wordy.answer('What is 1 2 plus?')
+    end, 'Invalid question')
+  end)
+
+  it('reject prefix notation', function()
+    assert.has_error(function()
+      wordy.answer('What is plus 1 2?')
+    end, 'Invalid question')
+  end)
+end)