.NET

C# and .NET - Past, Present, Future

February 13th, 2002

🔗

Linux is a cancer that attaches itself in an intellectual property sense to everything it touches.

Google?

Facebook?

Meta?

Image source: https://de.wikipedia.org/wiki/Newton_(PDA)#/media/Datei:Apple_Newton.jpg

Hyper-V?

κυβερνήτης?

Containers?

Servers...

Image Sources: https://commons.wikimedia.org/wiki/File:Computer_server_rack.jpg
https://www.flickr.com/photos/pascalmaramis/8916250698

...like Tamagotchis

🔗

A little bit
of history...

A little bit of history...

  • .NET Framework at its beginnings
    • Windows only
    • Closed source
  • Mono appeared
    • Separate implementation
    • Open-source, cross platform
  • .NET Core
    • Lean, modern .NET
    • Open-source, cross platform
    • Grew bigger over time
  • Back to one .NET

.NET Standard

One
.NET

.NET Unification Vision

Cloud Readiness

  • Protocols and APIs
  • Packaging and Runtimes
  • Efficiency
  • Startup Performance
  • Productivity

Protocols and APIs

Yet Additional JSON APIs??

  • Support for streaming through IAsyncEnumerable 🔗
    • Significant performance improvement in some scenarios
  • JSON Writeable DOM API 🔗
    • For scenarios in which POCOs are not an option
      • Data structures not known at runtime
    • Potential for perf optimization
      • Deserialize only a subtree of large JSON in POCOs
      • Manipulate a subtree without deserializing everything into POCOs

Demo
Time!

https://github.com/rstropek/Samples/blob/master/DotNet6/JsonApis/Program.cs

var builder = WebApplication.CreateBuilder(args);
var app = builder.Build();
app.UseHttpsRedirection();

app.MapGet("/ping", () => "pong");
app.Run();

C#

const express = require('express')
const app = express()

app.get('/', (req, res) => {
  res.send('Hi!')
})

app.listen(3000, () =>
  console.log('Server ready'))

😁👍

Node.js

Web API

Language supports framework enhancements

using System;

// In the past, we had to use explicit type for lambdas:
Func<int> f = () => 42;

// Lambdas will have a "natural type" that is compatible with var:
var f2 = () => 42;

// We will be able to call lambdas directly:
Console.WriteLine((() => 42)());

Lambda Improvements

Demo
Time!

Create new minimal Web API

Packaging and Runtimes

Demo
Time!

https://github.com/rstropek/StarshipTraveler

Efficiency and Performance

https://www.techempower.com/benchmarks/#section=data-r20&hw=cl&test=composite

Performance and efficiency is important
for Microsoft and the .NET community

ReadyToRun File Format

  • Goal: Binary file format for better startup performance
    • Form of ahead of time compilation (AOT)
    • Not full native AOT
    • "Run anywhere" code ranging from full JIT to full AOT (flexible)
    • Re-JITted after start for better steady-state performance
  • Drawbacks
    • Larger file sizes
    • Specific for target architecture (e.g. Win x64)
  • Publish as ReadyToRun 🔗
    • In .NET 6: Crossgen2 replaces Crossgen
    • CLI (dotnet publish ... -p:PublishReadyToRun=true)
    • .csproj (<PublishReadyToRun>true</PublishReadyToRun>)

Conversation about  ReadyToRun

Demo
Time!

Publish trimmed R2R

Memory Management

  • Span<T>, Memory<T>
    • Unified programming model over different storage types
  • Memory pools (System.Buffers)
  • Reduce pressure on GC leads to better performance

Demo
Time!

https://github.com/rstropek/Samples/blob/master/CSharp7/SpansInsideOut/Spans/Program.cs

Startup Performance

https://docs.microsoft.com/en-us/dotnet/csharp/roslyn-sdk/source-generators-overview

What's a Code Generator?

  • Runs during compilation
  • Inspects your program (using Roslyn)
  • Produces additional files that are compiled together with your app

Code Generator Documentation

Why Code Generators?

  • Currently:
    • Runtime reflection, e.g. ASP.NET Core DI (impacts performance)
    • Change IL after compilation ("IL weaving")
    • MSBuild tasks
  • In the future:
    • Analyse code at compile time and generate code
    • Less reflection leads to...
      • ...better performance
      • ...smaller apps because AoT compiler (linker) can remove unused parts of your code

Demo
Time!

https://github.com/rstropek/Samples/blob/master/DotNet6/LinkerLibrary/DummyClass.cs

Does the language even matter?

Feature-Rich Language

  • Express intention clearly and concisely
    • Code is easy to maintain (read, understand, write)

​Ensure high developer productivity

Demo
Time!

https://github.com/rstropek/Samples/blob/master/CSharp11/PatternMatchingInsideOut/Program.cs
   https://github.com/rstropek/Samples/tree/master/CSharp10/RecordsInsideOut

billion-dollar mistake.

I call it the

It was the invention of the null reference in 1965.

Tony Hoare

Demo
Time!

Nullable References

https://inf.news/en/fitness/6d35995b75d4c418e8ab2b172f2f3d83.html

.NET

C# and .NET - Past, Present, Future