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.NET Interactive combines the power of .NET with many other languages to create notebooks, REPLs, and embedded coding experiences. Share code, explore data, write, and learn across your apps in ways you couldn't before.

Language: C#

#5 in C#
Hi! My name is Claudia and I am a PM at Microsoft (opinions are my own) working on Polyglot Notebooks in VS Code. Polyglot Notebooks are exactly what you are describing! They are notebooks where you can use multiple languages AND share variables between them to ensure a continuous workflow. Not only that, but each language has language server support. Polyglot Notebooks currently supports C#, F#, PowerShell, JavaScript, HTML, SQL, KQL, and Mermaid.

We have just added support for Python and R integration and I am actually in search of external testers! If you are willing to sign an NDA to try out our Python and R integration and give us feedback please drop your email in the form below and I will reach out with instructions for you to try it out!

https://forms.office.com/r/UQchfQSGa5

If you'd like to start trying it out today you can install the extension from the marketplace here: https://marketplace.visualstudio.com/items?itemName=ms-dotne...

https://github.com/dotnet/interactive

Yes, please do! Warning: F# will ruin other languages for you. I find it rather painful to work in basically anything else after using F#, with gradients of pain for different languages. Haha.

And that's a good question. I have basically every book written on F#, but I can't say I have ever used them for anything more than reference.

The official docs/guide/reference are actually really good, and I refer to them a lot when using some feature I'm not familiar with: https://docs.microsoft.com/en-us/dotnet/fsharp/what-is-fshar...

F# For Fun and Profit is well-known, but I can't say I use it a lot: https://fsharpforfunandprofit.com/

The same author's (Scott Wlaschin) book is very good: https://pragprog.com/titles/swdddf/domain-modeling-made-func...

As for books, I have always liked:

* Functional Programming Using F# by Hansen and Rischel (might be too simple if you are already comfortable with functional programming and is out of date every now and then with changes to F# that's happened)

* Expert F# 4.0 by Don Syme and others (contains a lot of nice things by the designer of F#

One of the latest books is Stylish F# 6: Crafting Elegant Functional Code for .NET 6 by Kit Eason. I have the first edition but haven't read it.

My personal recommendation is to take the approach of type/domain driven design. That is, I start off every F# module the same:

1. Define my types with discriminated unions, records, type aliases (such as for tuples) or single case discriminated unions. Use classes when necessary but try to prefer the more functional types.

2. Start writing functions against these.

And that's basically it. One thing to recognize with F# is that it mixes OOP rather nicely. Even discriminated unions and records, which are immutable, can have members defined on them, including operator overloading (something F# is pretty good about). They can even implement interfaces and be defined with generic types, which is also nice and powerful.

I have some projects that might of interest, since they're simple enough and illustrate the above process.

https://github.com/bmitc/the-ray-tracer-challenge-fsharp

https://github.com/bmitc/nand2tetris

Lastly, I'd suggest just starting up some projects. You could also take the Programming Languages course on Coursera by Dan Grossman. Part A uses SML, and you could port the examples and homework solutions to F# (I did so when I took the course). I also take books written for other languages and port the code to F#, usually taking a more idiomatic functional style. .NET Interactive notebooks (https://github.com/dotnet/interactive) are a great way to get started. You just need to install the .NET 6 SDK (which gets you F#) and then install the .NET Interactive Notebook extension in VS Code. That's it. There is also the book The Little MLer which gets people comfortable with discriminated unions (sum types), and I used the book and ported the examples to F#. I need to go back and finish that annotation project (https://github.com/bmitc/the-little-fsharper). I'll probably convert the script files to .NET Interactive notebooks if I do.

Note: you can create jupyter book with C# or F#

https://github.com/dotnet/interactive

On the .NET team, we're working on a polyglot Jupyter kernel that includes C#, F#, and PowerShell support. We're collaborating with the Azure Data and PowerShell teams. It's in preview now. https://github.com/dotnet/interactive