Fully embrace INumber and generic math of .NET 7

[bitbonk]

.NET 7 will introduce the INumber<TSelf> interface (along with accompanying with C# 11 features) that make a feature called generic math possible.

I think this would be a perfect fit for the quantities of UnitsNet and could potentially make the usage way more intuitive, flexible and overall enjoyable.

Please consider to fully embrace INumber<TSelf> and generic math in a future version of UnitsNet.

Here is a short introduction to this feature set by @MadsTorgersen (first 25 minutes): Where's C# headed? - Mads Torgersen - NDC Copenhagen 2022
Official documentation: https://docs.microsoft.com/en-us/dotnet/standard/generics/math

[tmilnthorp]

The biggest question is the supported deployments. Do we abandon netstandard/netframework support just for generic math? Neither are EOL yet.

[bitbonk]

You could only support it a future mayor version without downlevel support. Also, would multitargeting be an option?

[tmilnthorp]

We already do, but without too many #ifs. I fear that the API support for generic math vs precompiled lambdas would be difficult to maintain with equivalent functionality. But definitely worth a try.

[bitbonk]

My guess would be that IQuantity<TUnitType> would need to derive from INumber<TSelf> somehow, right?

[angularsen]

@bitbonk An early prototype here to explore how it can be used.
#984

I haven't yet looked into what the changes were compared to the experimental interfaces at the time, but I assume it is in the ballpark similar.

[stale]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.

[angularsen]

Some support for generic math was added in #1164 , it can be extended further.

[bitbonk]

Some support for generic math was added in #1164 , it can be extended further.

Awesome! What version of UnitsNet has generic math included?

[angularsen]

v5 has it 👍 There are a couple of extension methods Sum() and Average() in GenericMathExtensions to help use it.

[angularsen]

https://github.com/angularsen/UnitsNet/pull/1164/files#diff-88adba83458faa7e4ec81b932cb85045c84f3b9e1b077bbc647167910cd07efa