The document provides a technical overview of various programming languages and their popularity, including Ruby, TypeScript, and Python. It discusses programming concepts such as pattern matching, asynchronous programming, and the structure of a 'person' class with its properties and methods. The content highlights various coding practices while detailing usage examples for advanced language features.

2. 9.1
9.5
19
22.3
28.1
32
34.1
39.7
51.2
62.5
0 10 20 30 40 50 60 70
Ruby
TypeScript
C
C++
PHP
Python
C#
Java
SQL
JavaScript
Percentage
Ruby TypeScript C C++ PHP Python C# Java SQL JavaScript

3. 0 10 20 30 40 50 60 70 80
Clojure
Scala
C#
Elixir
Python
Go
Swift
TypeScript
Smalltalk
Rust
Percentage
Clojure Scala C# Elixir Python Go Swift TypeScript Smalltalk Rust

4. C#
1,000,000’s
Millions
VB
F#
100,000’s
Hundreds of thousands
10,000’s
Tens of thousands

5. It’s there use it
First point release – tiny features
Safe efficient low level code
Next steps for pattern matching
Major features

6. IAsyncEnumerable<Person> people = database.GetPeopleAsync();
foreach await (var p in people) { … }
using await (IAsyncDisposable resource = await store.GetRecordAsync(…)) { … }

7. extension Enrollee extends Person
{
// static field
static Dictionary<Person, Professor> enrollees = new Dictionary<Person, Professor>();
// instance method
public void Enroll(Professor supervisor) { enrollees[this] = supervisor; }
// instance property
public Professor Supervisor => enrollees.TryGetValue(this, out var supervisor) ? supervisor : null;
// static property
public static ICollection<Person> Students => enrollees.Keys;
// instance constructor
public Person(string name, Professor supervisor) : this(name) { this.Enroll(supervisor); }
}

8. class Person : IEquatable<Person>
{
public string First { get; }
public string Last { get; }
public Person(string First, string Last) => (this.First, this.Last) = (First, Last);
public void Deconstruct(out string First, out string Last)
=> (First, Last) = (this.First, this.Last);
public bool Equals(Person other)
=> other != null && First == other.First && Last == other.Last;
public override bool Equals(object obj) => obj is Person other ? Equals(other) :
false;
public override int GetHashCode() => GreatHashFunction(First, Last);
…
}
class Person(string First, string Last);