Meeting notes: Add new notes for Feb 26, March 9

[agocke]

March 9, 2020

C# Language Design Notes for March 9, 2020

1. Simple programs

2. Records

Feb 26, 2020

C# Language Design Notes for Feb. 26, 2020

Design Review

[YairHalberstadt]

I believe the links are the wrong way round

[Joe4evr]

• One of the biggest drawbacks of the current writeable-property style in C#, where types are declared with public mutable properties that are then initialized using object initializers, is that author can't enforce that certain properties are always initialized. It would be a big disappointment if any "nominal records" feature that we built couldn't support this feature.

Once again, I'd like to point the LDM's attention to #2328 which can simply be another building block.

[agocke]

I believe the links are the wrong way round

Fixed!

#2328

Good to know. Personally I'm not sure I buy a separate feature here. I think the concept is valid for init-only properties, but properties with public setters can have any value set at any time, so I'm not convinced it's useful.

[MgSam]

I still don't see what problem you guys are trying to solve with "simple programs". As you stated clearly in the design notes- it's impossible to reconcile with CSX. So is introducing a 3rd variant of C# really worth all the added complexity for the tiny marginal benefit? What is wrong with CSX exactly?

Are "learners" really an important target audience? C# is 20 years old and has consistently been one of the top used languages. Obviously, a lot of people have learned how to use it without requiring top-level statements.

[333fred]

I still don't see what problem you guys are trying to solve with "simple programs".

Jupyter notebook scripting and other top-level programs are starting to become more popular. We want to make the transition between a notebook and a full C# program as seamless as possible, namely copy-paste with no additional work. We think that's well worth the costs. Personally, I'm also quite excited by the potential for a real front-and-center single file solution in dotnet itself, that's indistinguishable from dotnet run. Because it literally is dotnet run.

[alrz]

I was thinking this could simplify Program.cs for .net hosted applications (aspnet, workers, etc), but in the simplest case we need args argument.

Would it be possible to define void Main(string[] args) as a top-level method?

[agocke]

You could probably use Environment.CommandLine for that case

[HaloFour]

@agocke

That would require some portion of that "simple program" be dedicated to parsing that single string of args. VB5/6 had similar limitations and it was a common/constant source of bugs, particularly given that (at the time) the string could be formatted differently on different OSes (9x vs. NT).

If C# isn't going to offer the args I would say that the BCL should add a method that would make it easy to obtain the args parsed correctly.