C# playground (compiler explorer) which runs entirely in a browser (via WebAssembly). Started as an alternative to SharpLab which is not maintained anymore. But it can also do some other stuff that I wanted like downloading any compiler version, and compiling Razor. Recently I've added some "IntelliSense" features to improve the editing experience.
What do you mean by incompatible? If you mean syntax, that's different intentionally for clarity and also we don't want to create a new C# scripting dialect hence it isn't possible to "import" other files (that's not how C# works).
You were already using F#'s syntax for C# NuGet references in .NET Interactive. Even NuGet itself labels this syntax "Script & Interactive" in its picker.
.NET interactive uses a dialect of C# - the script dialect. With file based apps, we strive to use the standard C#, so you can convert file based apps to full projects at any time.
That doesn't explain why standard C# had to deviate further from the script dialect just for import directives. These directives don't interfere with the rest of the grammar.
Is #:package <pkg> really so much nicer than #r "nuget: <pkg>" as to deserve deviating from .NET Interactive, F# and the existing NuGet picker? (It could be, if properly argued!) Has there been any effort to have the rest of .NET adopt this new syntax or share concerns?
On that note, is any language other than C# supported for `dotnet run`? Is the machinery at least documented for other MSBuild SDKs to use? Considering how dotnet watch keeps breaking for F#, I suspect not.
> Is #:package <pkg> really so much nicer than #r "nuget: <pkg>" as to deserve deviating from .NET Interactive, F# and the existing NuGet picker? (It could be, if properly argued!)
Yes, we believe so. There is not much to be gained from reusing the syntax (it's not like you can import cs from csx or vice versa). We are also adding other directives, e.g., `#:property` - it would not make sense to reuse `#r` for that. `#r` is short for "reference", because it was originally meant for referencing DLLs which is discouraged in modern .NET. The main motivation for file-based programs is to lower the entry barrier, and having opaquely named directives like `#r` seems counter-productive.
> On that note, is any language other than C# supported for `dotnet run`?
> Is the machinery at least documented for other MSBuild SDKs to use?
There is really not much special machinery, an in-memory csproj file is created and built via MSBuild just like an on-disk csproj would. Any MSBuild SDK can be used via the `#:sdk` directive.
>referencing DLLs which is discouraged in modern .NET
You can't do much of anything in .NET without referencing Nuget assemblies.
> opaquely named directives like `#r` seems counter-productive
Then why is it the existing standard?
Agreeing with others, '#r "nuget:' should at least be an option.
And otherwise (but I guess regarless if you stick with this syntax) you will have to add another tab to Nuget called "dotnet run". "Script & Interactive" is already present in Nuget and shows the #r syntax for a reference.
> You can't do much of anything in .NET without referencing Nuget assemblies.
And referencing NuGet assemblies is of course supported via the #:package directive. It's just that referencing DLLs directly is not a common scenario, hence it's not supported for now (but can be added later).
> Agreeing with others, '#r "nuget:' should at least be an option.
> And otherwise (but I guess regarless if you stick with this syntax) you will have to add another tab to Nuget called "dotnet run". "Script & Interactive" is already present in Nuget and shows the #r syntax for a reference.
Agree but also note that the ".NET CLI" tab which tells you to run "dotnet add package" should also work in near future, see https://github.com/dotnet/sdk/issues/49200.
> we don't want to create a new C# scripting dialect hence it isn't possible to "import" other files (that's not how C# works)
This statement is a bit confusing. From a user perspective, "dotnet run" does add a new scripting dialect. I would like to rewrite all my csx utilities to use this.
I've been using dotnet-script for several years for both unit testing code and for creating small utilities. Being able to load scripts (with "#load - see below) from other scripts is a core feature for keeping my code DRY. It would be a knock against "dotnet run" if a comparable syntax was not available. It's just a preprocessor - not a change to the C# syntax. Just like the other '#:' preprocessors being added.
> From a user perspective, "dotnet run" does add a new scripting dialect.
By dialect I mean that in CSX, the C# language has subtle differences in behavior compared to CS files (e.g., top-level methods are compiled differently). In 'dotnet run app.cs', the C# is exactly the same, hence it can be converted to a project (and we have a command for that - 'dotnet project convert').
> It's just a preprocessor - not a change to the C# syntax.
Should #:load work in normal C# files as well then? If yes, we would have two ways to include files - the normal way (include them in the project) or via #:load. If not, how would 'dotnet project convert' work? (It could paste the text but that's not very DRY if it's imported at multiple places.)
That's in short why #:load doesn't play very nicely with existing C# (it's a different paradigm of including other files). So the current proposal is to just make files in the same folder visible (just like they would be for a .csproj), because that's consistent with current C#, 'dotnet project convert' works, etc. But this proposal is not final yet, there are other options including what you suggest - see https://github.com/dotnet/sdk/issues/49193.
Assembly references are not really a mainline scenario, hence we support nuget package references only for now. And `#r` is just too opaque (it comes from old times when assembly references were the norm).
I have to agree with others that it's strange this has not been in line with .net interactive and the usage of "#r" there. I think "#r" should at least be an option.
You say that importing other files is not how c# works, but I think that's not entirely true. If you now treat a file as a project then an import is pretty much a project reference just to a .cs file instead of a .csproj file.
So I'd love to see something like that working:
#:reference ./Tools.cs
Which should be the same as a ProjectReference in csproj or for a "real" project something like this:
#:reference ./Tools/Tools.csproj
That would also enable things like this in a csproj file:
<ProjectReference Include="..\Tools\Helpers.cs" />
Referencing other projects is currently out of scope (and might always be, file based programs are intended to be simple), you can convert file based programs to full projects though to regain full functionality.
I disagree, this is the kind of decisions that make CLR the C# Language Runtime, instead of its original purpose, where there was an ecosystem of common approaches.
Unless you plan to also support the same approach on VB and F# scripts.
F# and C# are intentionally different languages, I don't think it makes sense to have 100% equivalent functionality in both. AFAIK, F# already has scripting functionality built in. VB support could be added, but that seems unlikely given https://learn.microsoft.com/en-us/dotnet/fundamentals/langua...
janjones, can you please advocate inside your team for taking F# seriously? It should have been a first class language inside .net.
I dread the moment C# introduces sum types (long overdue) and then have them incompatible with F#. On a general note, the total disregard towards F# is very much undeserved. It is far superior to the likes of Python, and would easily be the best in the areas of machine learning and scripting, but apparently nobody inside MS is that visionary.
> It is far superior to the likes of Python, and would easily be the best in the areas of machine learning...
The fact that Python is the language of choice for ML makes it clear that technical superiority was not necessary or relevant. Python is the worst language around. The lack of better languages was never the problem. Making F# technically better wasn't going to make it the choice for ML.
Agreed. But MS has certainly some weight to throw around in their own ecosystem. They have their own offerings for data processing and ambitions for AI. If they want to integrate with .net, they are already set. But that requires vision.
Note that until the layoffs of the week predating BUILD, Microsoft was exactly one of the companies pushing for improving CPython performance.
This is why I always mention, when .NET team complains about adoption among new generations not going as desired they should look into their own employer first.
https://lab.razor.fyi/
GitHub: https://github.com/jjonescz/DotNetLab