AspNetCoreDiagnosticScenarios VS SharpLab

Important: following #prefer-asyncawait-over-directly-returning-task from https://github.com/davidfowl/AspNetCoreDiagnosticScenarios/b... is not correct.

The concerns raised are niche and edge case and task must always be forwarded as is provided there is no post-processing or resource cleanup with idisposable.

This one is a pretty decent guide - https://github.com/davidfowl/AspNetCoreDiagnosticScenarios/blob/master/AsyncGuidance.md

The C# (mostly applicat community has e.g. https://github.com/davidfowl/AspNetCoreDiagnosticScenarios/blob/master/AsyncGuidance.md written by one of the Asp.Net architects. I found this in this lovely thread https://news.ycombinator.com/item?id=36785691 which expresses my views/confusion more clearly than I can express.

No it doesn't, hence why there are best practices guidelines written by the .NET architects, and there was a research project to add Go/Java co-routines as well.

https://github.com/davidfowl/AspNetCoreDiagnosticScenarios/b...

https://twitter.com/davidfowl/status/1532880744732758018?lan...

https://github.com/dotnet/runtimelab/issues/2057

https://github.com/dotnet/runtimelab/issues/2398

They don't work just fine in C#, there is a reason why one of ASP.NET architects has written a guide of best practices.

https://github.com/davidfowl/AspNetCoreDiagnosticScenarios/b...

Many that praise async/await in C#, kind of forget it took about 10 years to spread across all the layer of the language and runtime, since it was done via IL rewriting, it caused several issues with F# async tasks, due to the age of the ecosystem plenty of code isn't async/await friendly and needs to be wrapped into Task.Run() or similar.

There is a best practices guideline from one of the ASP.NET architects, https://github.com/davidfowl/AspNetCoreDiagnosticScenarios/b...

During last year they researched adding Go/Java's approach to .NET, but now it is too late. See the ASP.NET Q&A session at BUILD 2023.

The best guidance I have found was from here: AsyncGuidance.md

To expand upon this thought, here is the AsyncGuidance doc[1] on why not to use .Result to get the return value of a completed Task in C#.

To make this simple they introduced async Main[2] a few years ago.

[1]: https://github.com/davidfowl/AspNetCoreDiagnosticScenarios/b...

Async Guidance

Do these all compile to the exact same thing?

https://sharplab.io/#v2:CYLg1APgAgTAjAWAFBQMwAJboMLoN7LpHoCW...

Yes, so you are right.

Recently, while creating some experimental C# source code generators (xafero/csharp-generators), I was just concatenating strings together. Like you do, you know, if things have to go very quickly. If you have a simple use case, use a formatted multi-line string or some template library like scriban. But I searched for a way to generate more and more complicated logic easily - like for example, adding raw SQL handler methods to my pre-generated DBSet-like classes for my ADO.NET experiment. You could now say: Use Roslyn and that's really fine if you look everything up in a website like SharpLab, which shows immediately the syntax tree of our C# code.

One results in MOVSX, the other in MOVZX [1]. The difference thus is sign/zero extension when moving to the larger register. However, they seem to perform pretty much identical if I'm reading Agner Fog's instruction tables correctly.

[1] https://sharplab.io/#v2:C4LghgzgtgPgAgJgIwFgBQcDMACR2DC2A3ut...

If you don't have an IDE, you can use SharpLab.io or dotnet fiddle

The closest online tool I can think of would be SharpLab, but you can only choose between Roslyn's git branches instead of C# versions.

Your code is destructuring two properties and discarding one of them. It doesn't work with a single property: https://sharplab.io/#v2:C4LgTgrgdgNAJiA1AHwAICYAMBYAUBgRj2Nw...

I think that records don't generate a deconstruct method when they only have one property, but even if you manually define one you'll get an error on `var (varName) = ...`

- LinqPad is great and I love, but, IMO, it is not the best tool to start with. It does not provide intellisense or debugger in the free version. Assuming you do not want to pay for this licence just to play a little with the language, I'd suggest https://sharplab.io/. It is not as powerfull as LinqPad, but at least it gives you suggestions.