Wordy Exercise

config.json

@@ -748,6 +748,14 @@
         "prerequisites": [],
         "difficulty": 2
       },
+      {
+        "slug": "wordy",
+        "name": "Wordy",
+        "uuid": "78d31713-0d88-4821-a586-4b36c46eaa44",
+        "practices": [],
+        "prerequisites": [],
+        "difficulty": 4
+      },
       {
         "slug": "high-scores",
         "name": "High Scores",

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 +1,22 @@
+{
+  "authors": [
+    "Ephraim-nonso"
+  ],
+  "files": {
+    "solution": [
+      "src/lib.cairo"
+    ],
+    "test": [
+      "tests/wordy.cairo"
+    ],
+    "example": [
+      ".meta/example.cairo"
+    ],
+    "invalidator": [
+      "Scarb.toml"
+    ]
+  },
+  "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.cairo

@@ -0,0 +1,148 @@
+#[derive(Drop, PartialEq)]
+enum Operator {
+    Plus,
+    Minus,
+    Multiply,
+    Divide,
+    Invalid,
+}
+
+pub fn answer(question: ByteArray) -> i32 {
+    let words: Array<ByteArray> = split_question_into_words(question);
+    assert!(words.len() >= 3, "syntax error");
+    assert!(words[0] == @"What" && words[1] == @"is", "unknown operation");
+
+    let mut result = match parse_int(words[2]) {
+        Option::Some(s) => s,
+        Option::None => panic!("syntax error")
+    };
+
+    let mut i = 3;
+    while i < words.len() {
+        let op = parse_operator(words.at(i));
+        i += 1;
+
+        if op == Operator::Multiply || op == Operator::Divide {
+            assert!(i < words.len() && words[i] == @"by", "unknown operation");
+            i += 1;
+        } else if op == Operator::Invalid {
+            assert!(parse_int(words.at(i - 1)) != Option::None, "unknown operation");
+        }
+
+        let num: i32 = match words.get(i) {
+            Option::Some(s) => {
+                match parse_int(s.unbox()) {
+                    Option::Some(s) => s,
+                    Option::None => panic!("syntax error"),
+                }
+            },
+            Option::None => panic!("syntax error"),
+        };
+
+        result = match op {
+            Operator::Plus => result + num,
+            Operator::Minus => result - num,
+            Operator::Multiply => result * num,
+            Operator::Divide => {
+                assert!(num != 0, "unknown operation");
+                result / num
+            },
+            Operator::Invalid => panic!("unknown operation"),
+        };
+
+        i += 1;
+    };
+
+    result
+}
+
+
+fn split_question_into_words(question: ByteArray) -> Array<ByteArray> {
+    let mut words: Array<ByteArray> = ArrayTrait::new();
+    let mut current_word = "";
+
+    let mut i = 0;
+    while i < question.len() {
+        let char = question[i];
+        if char == ' ' {
+            if current_word.len() > 0 {
+                words.append(current_word);
+                current_word = "";
+            }
+        } else if char == '?' {
+            if current_word.len() > 0 {
+                words.append(current_word);
+                current_word = "";
+            }
+            break;
+        } else {
+            current_word.append_byte(char);
+        }
+        i += 1;
+    };
+
+    words
+}
+
+
+fn parse_int(num: @ByteArray) -> Option<i32> {
+    let mut result: Option<i32> = Option::Some(0);
+    let mut size = num.len();
+    let mut i = 0;
+
+    let mut is_signed = false;
+    if num.at(i).unwrap() == '-' {
+        is_signed = true;
+        i += 1;
+    }
+
+    while i < size {
+        let re = char_to_digit(num[i]);
+        match re {
+            Option::Some(v) => {
+                if let Option::Some(max) = result {
+                    result = Option::Some(max * 10 + v.into());
+                }
+            },
+            Option::None => {
+                result = Option::None;
+                break;
+            }
+        }
+        i += 1;
+    };
+
+    if let Option::Some(val) = result {
+        if (is_signed) {
+            result = Option::Some(val * -1)
+        }
+    }
+    result
+}
+
+fn parse_operator(word: @ByteArray) -> Operator {
+    if (word == @"plus") {
+        Operator::Plus
+    } else if (word == @"minus") {
+        Operator::Minus
+    } else if (word == @"multiplied") {
+        Operator::Multiply
+    } else if (word == @"divided") {
+        Operator::Divide
+    } else {
+        Operator::Invalid
+    }
+}
+
+
+// Utility function to convert a char representing a digit into its numerical value (u32 equivalent)
+fn char_to_digit(c: u8) -> Option<u8> {
+    let zero_ascii = '0';
+    let nine_ascii = '9';
+
+    if c >= zero_ascii && c <= nine_ascii {
+        Option::Some(c - zero_ascii)
+    } else {
+        Option::None // Return None for invalid characters
+    }
+}

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/Scarb.toml

@@ -0,0 +1,7 @@
+[package]
+name = "wordy"
+version = "0.1.0"
+edition = "2024_07"
+
+[dev-dependencies]
+cairo_test = "2.8.2"

exercises/practice/wordy/src/lib.cairo

@@ -0,0 +1,3 @@
+pub fn answer(question: ByteArray) -> i32 {
+    panic!("implement `answer`")
+}