✨ (concepts) Add new concept exercise phone-number-analysis

This is inspired by the same in csharp track. Provides a gentle introduction to tuples.

Author: devkabiir

config.json

@@ -35,6 +35,20 @@
   },
   "exercises": {
     "concept": [
+      {
+        "slug": "phone-number-analysis",
+        "uuid": "eabea697-cc15-472f-ab4e-5b2720a180d1",
+        "name": "Phone Number Analysis",
+        "difficulty": 1,
+        "concepts": [
+          "tuples"
+        ],
+        "prerequisites": [
+          "strings",
+          "booleans"
+        ],
+        "status": "wip"
+      },
       {
         "slug": "lucians-luscious-lasagna",
         "uuid": "29a2d3bd-eec8-454d-9dba-4b2d7d071925",

exercises/concept/phone-number-analysis/.docs/hints.md

@@ -0,0 +1,27 @@
+# Hints
+
+## General
+
+- [Tuples][tuples]: shows how to define and use tuples.
+
+## 1. Analyze a phone number
+
+- Make sure the tuple has values at the right place. 
+- Tuples are passed as a [return value][tuples-return].
+
+- Use `.split_at()` method on a string to split it and get a tuple of its parts.
+    ```rust
+    let str = "Per Martin-Löf";
+
+    let (first, last) = str.split_at(3);
+
+    first // => "Per"
+    last // => " Martin-Löf"
+    ```
+
+## 2. Detect if a phone number is fake prefix code (555)
+
+- You can extract the value of a field with the same sort of dot syntax as you employ with `struct`s or `class`s.
+
+[tuples]: https://doc.rust-lang.org/book/ch03-02-data-types.html#the-tuple-type
+[tuples-return]: https://docs.microsoft.com/en-us/dotnet/csharp/tuples#tuples-as-method-return-values

exercises/concept/phone-number-analysis/.docs/instructions.md

@@ -0,0 +1,32 @@
+# Instructions
+
+This exercise has you analyze phone numbers.
+
+You are asked to implement 2 features.
+
+Phone numbers passed to the routines are guaranteed to be in the form
+NNN-NNN-NNNN e.g. 212-515-9876.
+
+## 1. Analyze a phone number
+
+Your analysis should return 3 pieces of data
+
+1. An indication of whether the number has a New York dialing code ie. 212 as the first 3 digits
+2. An indication of whether the number is fake having 555 as a prefix code in positions 5 to 7 (numbering from 1)
+3. The last 4 digits of the number.
+
+Implement the function `analyze()` to produce the phone number info.
+
+```rust
+analyze("631-555-1234");
+// => (false, true, "1234")
+```
+
+## 2. Detect if a phone number has a fake prefix code (555)
+
+Implement the function `is_fake()` to detect whether the phone number is fake using the phone number info produced in task 1.
+
+```rust
+is_fake(analyze("631-555-1234"));
+// => true
+```

exercises/concept/phone-number-analysis/.docs/introduction.md

@@ -0,0 +1,114 @@
+# Introduction
+
+## Tuples
+
+A _tuple_ is a general way of grouping together a number of values with a variety of types into one compound type. Tuples have a fixed length: once declared, they cannot grow or shrink in size.
+
+We create a tuple by writing a comma-separated list of values inside parentheses. Each position in the tuple has a type, and the types of the different values in the tuple don’t have to be the same.
+We’ve added optional type annotations in this example:
+
+```rust
+let my_tuple: (i32, f64, u8) = (500, 6.4, 1);
+```
+
+The variable `my_tuple` binds to the entire tuple because a tuple is considered
+a single compound element.
+To get the individual values out of a tuple, we can use pattern matching to
+destructure a tuple value, like this:
+
+```rust
+let (x, y, z) = my_tuple;
+
+println!("{}", y); 
+// => 6.4
+
+```
+
+This program first creates a tuple and binds it to the variable `my_tuple`.
+It then uses a pattern with let to take `my_tuple` and turn it into three separate variables, `x`, `y`, and `z`.
+This is called _destructuring_ because it breaks the single tuple into three
+parts.
+Finally, the program prints the value of `y`, which is `6.4`.
+
+Sometimes, when _destructuring_ a tuple, some values might not be important or
+needed, these can be discarded by labeling them with "`_`" (underscore).
+
+```rust
+let (_, y, _) = my_tuple;
+
+println!("{}", y);
+// => 6.4
+
+```
+
+We can also access a tuple element directly by using a period (.) followed by the index of the value we want to access.
+For example:
+
+```rust
+let my_tuple: (i32, f64, u8) = (500, 6.4, 1);
+
+let five_hundred = my_tuple.0;
+
+let six_point_four = my_tuple.1;
+
+let one = my_tuple.2;
+```
+
+This program creates the tuple `my_tuple` and then accesses each of its elements using their respective indices.
+As with most programming languages, the first index in a tuple is 0.
+
+A tuple can contain 0, or upto 12 elements. A tuple with zero elements has a
+special name, _unit_.
+
+```rust
+let my_zero_tuple = ();
+let my_tuple = (1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12);
+```
+
+### Calling methods
+One can call any methods on a value held by a tuple by either first destructuring that value out of the tuple or accessing it using it's index.
+
+```rust
+let my_tuple = (12, "hello");
+
+let (my_num, my_str) = my_tuple;
+
+my_str.to_uppercase();
+
+// OR
+
+my_tuple.1.to_uppercase();
+```
+
+### Functions can accept a tuple as a parameter.
+Accepting a tuple as a parameter requires to explicitly define its type. The
+following example illustrates that.
+
+```rust
+fn my_function(my_tuple: (i32, &str)) {
+    // Do something with my_tuple
+}
+```
+
+### Functions can return tuple as a result.
+Returning a tuple as a result requires to explicitly define its type. The
+following example illustrates that.
+
+```rust
+fn make_tuple(an_int: i32, a_string: &str) -> (i32, &str) {
+    return (an_int, a_string);
+}
+```
+
+### Methods can return tuple as a result.
+Methods on various types sometimes return a tuple as a result. Consider the
+following example of a `&str` variable's `.split_at()` method.
+
+```rust
+let str = "Per Martin-Löf";
+
+let (first, last) = str.split_at(3);
+
+first // => "Per"
+last // => " Martin-Löf"
+```

exercises/concept/phone-number-analysis/.gitignore

@@ -0,0 +1,8 @@
+# Generated by Cargo
+# will have compiled files and executables
+/target/
+**/*.rs.bk
+
+# Remove Cargo.lock from gitignore if creating an executable, leave it for libraries
+# More information here http://doc.crates.io/guide.html#cargotoml-vs-cargolock
+Cargo.lock

exercises/concept/phone-number-analysis/.meta/config.json

@@ -0,0 +1,18 @@
+{
+  "authors": [
+    "devkabiir"
+  ],
+  "files": {
+    "solution": [
+      "src/lib.rs",
+      "Cargo.toml"
+    ],
+    "test": [
+      "tests/phone-number-analysis.rs"
+    ],
+    "exemplar": [
+      ".meta/exemplar.rs"
+    ]
+  },
+  "blurb": "Learn about tuples by analysing phone numbers."
+}

exercises/concept/phone-number-analysis/.meta/design.md

@@ -0,0 +1,23 @@
+# Design
+
+## Learning objectives
+
+- Know of the existence of tuples.
+- Know how to assigne a tuple.
+- Know how to access a value held by a tuple.
+- Know how to return a tuple as a result.
+- Know how to destructure tuple values into variables.
+- Know how to accept a tuple as a parameter.
+
+## Out of scope
+
+
+## Concepts
+
+- `tuples`
+
+## Prerequisites
+
+- `strings`
+- `if-statements`
+- `booleans`

exercises/concept/phone-number-analysis/.meta/exemplar.rs

@@ -0,0 +1,13 @@
+pub fn analyze(phone_number: &str) -> (bool, bool, &str) {
+    let (dial_code, number) = phone_number.split_at(3);
+
+    let (prefix_code, last_4_with_dash) = number.split_at(4);
+
+    let (_, last_4) = last_4_with_dash.split_at(1);
+
+    (dial_code == "212", prefix_code == "-555", last_4)
+}
+
+pub fn is_fake(info: (bool, bool, &str)) -> bool {
+    info.1
+}

exercises/concept/phone-number-analysis/Cargo.toml

@@ -0,0 +1,4 @@
+[package]
+name = "phone_number_analysis"
+version = "0.1.0"
+edition = "2021"

exercises/concept/phone-number-analysis/src/lib.rs

@@ -0,0 +1,7 @@
+pub fn analyze(_phone_number: &str) -> (bool, bool, &str) {
+    unimplemented!("Implement analyze")
+}
+
+pub fn is_fake(_info: (bool, bool, &str)) -> bool {
+    unimplemented!("Implement is_fake")
+}

exercises/concept/phone-number-analysis/tests/phone-number-analysis.rs

@@ -0,0 +1,59 @@
+#[test]
+pub fn analyze_non_fake_non_newyork() {
+    assert_eq!(
+        (false, false, "1234"),
+        phone_number_analysis::analyze("631-502-1234")
+    );
+}
+
+#[test]
+#[ignore]
+pub fn analyze_fake_non_newyork() {
+    assert_eq!(
+        (false, true, "1234"),
+        phone_number_analysis::analyze("631-555-1234")
+    );
+}
+
+#[test]
+#[ignore]
+pub fn analyze_non_fake_newyork() {
+    assert_eq!(
+        (true, false, "1234"),
+        phone_number_analysis::analyze("212-502-1234")
+    );
+}
+
+#[test]
+#[ignore]
+pub fn analyze_fake_newyork() {
+    assert_eq!(
+        (true, true, "1234"),
+        phone_number_analysis::analyze("212-555-1234")
+    );
+}
+
+#[test]
+#[ignore]
+pub fn analyze_fake_fake() {
+    assert_eq!(
+        (false, false, "1234"),
+        phone_number_analysis::analyze("515-212-1234")
+    );
+}
+
+#[test]
+#[ignore]
+pub fn is_fake_fake() {
+    assert!(phone_number_analysis::is_fake(
+        phone_number_analysis::analyze("212-555-1234")
+    ));
+}
+
+#[test]
+#[ignore]
+pub fn is_fake_non_fake() {
+    assert!(!phone_number_analysis::is_fake(
+        phone_number_analysis::analyze("555-212-1234")
+    ));
+}