Add wordy exercise (#72)

Author: keiravillekode

config.json

@@ -497,6 +497,14 @@
         "prerequisites": [],
         "difficulty": 8
       },
+      {
+        "slug": "wordy",
+        "name": "Wordy",
+        "uuid": "bcfdd937-5cbb-4ac3-80f9-818724d87c4c",
+        "practices": [],
+        "prerequisites": [],
+        "difficulty": 8
+      },
       {
         "slug": "zebra-puzzle",
         "name": "Zebra Puzzle",

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 +1,19 @@
+{
+  "authors": [
+    "keiravillekode"
+  ],
+  "files": {
+    "solution": [
+      "wordy.fut"
+    ],
+    "test": [
+      "test.fut"
+    ],
+    "example": [
+      ".meta/example.fut"
+    ]
+  },
+  "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.fut

@@ -0,0 +1,56 @@
+
+def atoi [n] (word: [n]u8): i32 =
+  let (sign, magnitude) = loop (sign, magnitude) = ('+', 0) for i < n - 1 do
+    if i == 0 && word[i] == '-' then ('-', magnitude) else
+    let digit = word[i] - '0'
+    in
+      assert (digit < 10) (sign, magnitude * 10 + i32.u8 digit)
+  in
+    if sign == '+' then magnitude else
+    -magnitude
+
+def equal [m] [n] (first: [m]u8) (second: [n]u8): bool =
+  if m != n then false else
+  let same = loop same = true for i < n do
+    if first[i] == second[i] then same else
+    false
+  in
+    same
+
+def find_offsets [n] (question: [n]u8): []i64 =
+  if length question == 0 then [] else
+  let offsets = loop offsets = [0] for i < n do
+    if question[i] != ' ' && question[i] != '?' then offsets else
+    if i > 0 && (question[i - 1] == 'd' || question[i - 1] == 't') && (question[i] == ' ') then offsets else
+    offsets ++ [i + 1]
+  in
+    offsets
+
+def question_mark_at_end [n] (word: [n]u8): bool =
+  let result = loop result = true for ch in word[0:n - 1] do
+    result && ch != '?'
+  in
+    result && word[n - 1] == '?'
+
+def calculate (first: i32) (operation: u8) (second: i32): i32 =
+  match operation
+    case '+' -> first + second
+    case '-' -> first - second
+    case '*' -> first * second
+    case '/' -> first / second
+    case _ -> assert false 0
+
+def answer (question: []u8): i32 =
+  let offsets = assert (question_mark_at_end question) (find_offsets question)
+  in
+    let (value, operation) = loop (value, operation) = (0, '^') for i < length offsets - 1 do
+      let word = question[offsets[i]:offsets[i + 1]]
+      in
+        if operation == '^' && equal word "What is " then (0, '+') else
+        if operation == '.' && equal word "plus " then (value, '+') else
+        if operation == '.' && equal word "minus " then (value, '-') else
+        if operation == '.' && equal word "multiplied by " then (value, '*') else
+        if operation == '.' && equal word "divided by " then (value, '/') else
+        assert (i % 2 == 1) (calculate value operation (atoi word), '.')
+    in
+      assert (operation == '.') value

exercises/practice/wordy/.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.
+
+[88bf4b28-0de3-4883-93c7-db1b14aa806e]
+description = "just a number"
+
+[18983214-1dfc-4ebd-ac77-c110dde699ce]
+description = "just a zero"
+
+[607c08ee-2241-4288-916d-dae5455c87e6]
+description = "just a negative number"
+
+[bb8c655c-cf42-4dfc-90e0-152fcfd8d4e0]
+description = "addition"
+
+[bb9f2082-171c-46ad-ad4e-c3f72087c1b5]
+description = "addition with a left hand zero"
+
+[6fa05f17-405a-4742-80ae-5d1a8edb0d5d]
+description = "addition with a right hand zero"
+
+[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/test.fut

@@ -0,0 +1,139 @@
+import "wordy"
+
+-- just a number
+-- ==
+-- input { "What is 5?" }
+-- output { 5 }
+
+-- just a zero
+-- ==
+-- input { "What is 0?" }
+-- output { 0 }
+
+-- just a negative number
+-- ==
+-- input { "What is -123?" }
+-- output { -123 }
+
+-- addition
+-- ==
+-- input { "What is 1 plus 1?" }
+-- output { 2 }
+
+-- addition with a left hand zero
+-- ==
+-- input { "What is 0 plus 2?" }
+-- output { 2 }
+
+-- addition with a right hand zero
+-- ==
+-- input { "What is 3 plus 0?" }
+-- output { 3 }
+
+-- more addition
+-- ==
+-- input { "What is 53 plus 2?" }
+-- output { 55 }
+
+-- addition with negative numbers
+-- ==
+-- input { "What is -1 plus -10?" }
+-- output { -11 }
+
+-- large addition
+-- ==
+-- input { "What is 123 plus 45678?" }
+-- output { 45801 }
+
+-- subtraction
+-- ==
+-- input { "What is 4 minus -12?" }
+-- output { 16 }
+
+-- multiplication
+-- ==
+-- input { "What is -3 multiplied by 25?" }
+-- output { -75 }
+
+-- division
+-- ==
+-- input { "What is 33 divided by -3?" }
+-- output { -11 }
+
+-- multiple additions
+-- ==
+-- input { "What is 1 plus 1 plus 1?" }
+-- output { 3 }
+
+-- addition and subtraction
+-- ==
+-- input { "What is 1 plus 5 minus -2?" }
+-- output { 8 }
+
+-- multiple subtraction
+-- ==
+-- input { "What is 20 minus 4 minus 13?" }
+-- output { 3 }
+
+-- subtraction then addition
+-- ==
+-- input { "What is 17 minus 6 plus 3?" }
+-- output { 14 }
+
+-- multiple multiplication
+-- ==
+-- input { "What is 2 multiplied by -2 multiplied by 3?" }
+-- output { -12 }
+
+-- addition and multiplication
+-- ==
+-- input { "What is -3 plus 7 multiplied by -2?" }
+-- output { -8 }
+
+-- multiple division
+-- ==
+-- input { "What is -12 divided by 2 divided by -3?" }
+-- output { 2 }
+
+-- unknown operation
+-- ==
+-- input { "What is 52 cubed?" }
+-- error: Error*
+
+-- Non math question
+-- ==
+-- input { "Who is the President of the United States?" }
+-- error: Error*
+
+-- reject problem missing an operand
+-- ==
+-- input { "What is 1 plus?" }
+-- error: Error*
+
+-- reject problem with no operands or operators
+-- ==
+-- input { "What is?" }
+-- error: Error*
+
+-- reject two operations in a row
+-- ==
+-- input { "What is 1 plus plus 2?" }
+-- error: Error*
+
+-- reject two numbers in a row
+-- ==
+-- input { "What is 1 plus 2 1?" }
+-- error: Error*
+
+-- reject postfix notation
+-- ==
+-- input { "What is 1 2 plus?" }
+-- error: Error*
+
+-- reject prefix notation
+-- ==
+-- input { "What is plus 1 2?" }
+-- error: Error*
+
+let main (question: []u8): i32 =
+  answer question

exercises/practice/wordy/wordy.fut

@@ -0,0 +1 @@
+def answer (question: []u8): i32 = ???