are-we-fast-yet VS csharplang

> Sure there's a small overhead to smart pointers

Not so small, and it has the potential to significantly speed down an application when not used wisely. Here are e.g. some measurements where the programmer used C++11 and did everything with smart pointers: https://github.com/smarr/are-we-fast-yet/issues/80#issuecomm.... There was a speed down between factor 2 and 10 compared with the C++98 implementation. Also remember that smart pointers create memory leaks when used with circular references, and there is an additional memory allocation involved with each smart pointer.

> Garbage collection has an overhead too of course

The Boehm GC is surprisingly efficient. See e.g. these measurements: https://github.com/rochus-keller/Oberon/blob/master/testcase.... The same benchmark suite as above is compared with different versions of Mono (using the generational GC) and the C code (using Boehm GC) generated with my Oberon compiler. The latter only is 20% slower than the native C++98 version, and still twice as fast as Mono 5.

See https://github.com/smarr/are-we-fast-yet/blob/master/docs/guidelines.md.

That's a very interesting article, thanks. Interesting to note that Cython is only about twice as fast as Python 3.10 and only about 40% faster than Python 3.11.

The official Python site advertises a speedup of 25% from 3.10 to 3.11; in the article a speedup of 60% was measured. It therefore usually makes sense to measure different algorithms. Unfortunately there is no Python or C++ implementation yet for https://github.com/smarr/are-we-fast-yet.

> Software benchmarks are super subjective.

No, they are not, but they are just a measurement tool, not a source of absolute thruth. When I studied engineering at ETH we learned "Who measures measures rubbish!" ("Wer misst misst Mist!" in German). Every measurement has errors and being aware of these errors and coping with it is part of the engineering profession. The problem with programming language benchmarks is often that the goal is to win by all means; to compare as fairly and objectively as possible instead, there must be a set of suitable rules adhered to by all benchmark implementations. Such a set of rules is e.g. given for the Are-we-fast-yet suite (https://github.com/smarr/are-we-fast-yet).

I am aware of the various published test results where CoreCLR shows fantastic speed-ups compared to Mono, e.g. when calculating MD5 or SHA hash sums.

But my measurements based on the Are-we-fast-yet benchmark suite (see https://github.com/smarr/are-we-fast-yet and https://github.com/rochus-keller/Oberon/tree/master/testcases/Are-we-fast-yet) show a completely different picture. Here the difference between Mono and CoreCLR (both versions 3 and 5) is within +/- 10%, so nothing earth shattering.

Here are my measurement results:

https://github.com/rochus-keller/Oberon/blob/master/testcases/Are-we-fast-yet/Are-we-fast-yet_results_linux.pdf comparing the same benchmark on the same machine run under LuaJIT, Mono, Node.js and Crystal.

https://github.com/rochus-keller/Oberon/blob/master/testcases/Are-we-fast-yet/Are-we-fast-yet_results_windows.pdf comparing Mono, .Net 4 and CoreCLR 3 and 5 on the same machine.

Here are the assemblies of the Are-we-fast-yet benchmark suite used for the measurements, in case you want to reproduce my results: http://software.rochus-keller.ch/Are-we-fast-yet_CLI_2021-08-28.zip.

I was very surprised by the results. Perhaps it has to do with the fact that I measured on x86, or that the benchmark suite used includes somewhat larger (i.e. more representative) applications than just micro benchmarks.

What are your opinions? Do others have similar results?

There is a good reason for this; have a look at e.g. https://github.com/smarr/are-we-fast-yet/blob/master/docs/guidelines.md.

Then apparently the SOM nbody program is taken as the basis of a new Java nbody program.

Certain parts of Microsoft Learn are permissive, for example the .NET BCL documentation is Creative Commons Attribution: https://github.com/dotnet/dotnet-api-docs as is ASP.NET Core: https://github.com/dotnet/AspNetCore.Docs (a good hint if documentation is permissively licensed and on GitHub is if there's an edit button at the top.)

The C# language specification is unfortunately a bit fuzzier: https://github.com/dotnet/csharplang/discussions/4855

The updated unified C# language specification is CC, but it's still catching up to modern C#: https://github.com/dotnet/csharpstandard

No OP, but for example you still see the C# folks still struggling to add discriminated unions to the language because of complex interactions due to its too many features[1]. Virtual threads are easier to use than async/await is another example.

[1] https://github.com/dotnet/csharplang/issues/113

For example, C# had a research fork called Spec# that had compile-time support for contracts, with keywords such as requires (for arguments) and ensures (for return values), all the way back in 2004. While still being discussed, it doesn't seem to be shipping any time soon.

Hi there. I'm the language designer who created the 'Collection Expression' design/specification: https://github.com/dotnet/csharplang/issues/5354

You can see the entire history of the proposal there. To answer you specific question, we went with `..` because that's what the language already uses for the complimentary 'pattern matching deconstruction' form for collection patterns.

In other words, you can already say this today:

    if (x is [var start, .. var middle, .. var end]) { ... }

You must specify concrete type.

There was a plan to have "natural type" so "var list = [1,2,3]" would be of type "List" but it was postponed to C# 13 (https://github.com/dotnet/csharplang/issues/5354#issuecommen...)

While C# currently lacks direct support for this kind of functionality, there's a glimmer of hope with an active proposal under discussion that aims to bring this feature to the language. This potential addition promises a future where C# can natively offer similar robust type narrowing.

Given few people anticipated ValueTuple and C# adding a more direct tuple syntax, I feel like it is only a matter of time before C# adds discriminated unions.

(There are multiple proposals tracking the idea. This seems the most comprehensive and "central": https://github.com/dotnet/csharplang/issues/7016)

I always liked list abbreviations in python, but I absolutely love Linq. I believe there is a feature proposal for C# 12, which makes collection initialization better imo.