ppx_deriving VS the-ray-tracer-challenge-fsharp

> You gave a beautiful answer about programming language

You do the same thing as in Rust, Scala or Haskell and derive the printer [1]. Then at the callsite, if you know the type then you do `T.show` to print it or `T.eq`. If you don't know the type, then you pass it in at the top level as a module and then do `T.show` or `T.eq`.

> Or to convert one type into another type?

If you want to convert a type, then you have a type that you want to convert from such as foo and bar, then you do `Foo.to_bar value`.

We can keep going, but you can get the point.

You _can't_ judge a language by doing what you want to do with one language in another. If I judge Rust by writing recursive data structures and complaining about performance and verbosity that's not particularly fair correct? I can't say that Dart is terrible for desktop because I can't use chrome developer tools on its canvas output and ignore it's hot-reloading server. I can't say Common Lisp code is unreadable because I don't have type annotations and ignore the REPL for introspection.

[1] https://github.com/ocaml-ppx/ppx_deriving

Ocaml has the amazing ppx_deriving which can be used for serialization / deserialization in various formats.

I wrote a CLI tool and I'd like to produce statically linked binaries of my tool. However, I cannot do this because I'm using the ppx_deriving deriving preprocessor, and I cannot produce a statically linked executable while using this package.

Not great, not terrible; the language supports annotations which mean nothing to the compiler but which pre-processors can take advantage of, and there is a framework called ppx which you can use to write your own preprocessor. There exist many pre-processors to do things like add inline tests, generate getter/setter/pretty-printing functions, and so on. Here is an example:

https://github.com/ocaml-ppx/ppx_deriving

is from https://github.com/ocaml-ppx/ppx_deriving

Have you tried to derive a print function using https://github.com/ocaml-ppx/ppx_deriving

However, there is a ppx (a pre-processor) which can do the job : ppx_deriving. You just have to anotate your type in oder to get the compare function automatically generated :

Take a book that is project-based, such as The Ray Tracer Challenge, no matter what language it uses in the book, and start going through the book in F#. I have done so, for example, here is my in-work F# implementation for the ray tracer book.

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.

Here's mine, which is only about halfway through: https://github.com/bmitc/the-ray-tracer-challenge-fsharp

I used FsUnit here: https://github.com/bmitc/the-ray-tracer-challenge-fsharp/tree/main/RayTracerChallenge/XUnitTests

Yes, the book has both implementations of the required functions (for all the complicated ones you need) and tests all written in pseudocode.

The book is really good. I have a half-finished implementation in F#, and what I find striking is just how close the F# code is to the pseudocode. I have also started an idiomatic port to Racket but have only done the tuples, vector, and point implementations so far. I need to pick these up again.

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

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

I mean, check this out: https://github.com/bmitc/the-ray-tracer-challenge-fsharp/blo...

I have also worked through pieces of Ray Tracing in One Weekend (what was referenced in this post). They get you going much faster, but the code is written in C++. I found the translation to a functional style was harder (was just using Racket and F#'s mutability features), whereas the way The Ray Tracer Challenge is laid out and specified, I found it much easier to translate to an idiomatic functional style.

Another project of mine is going through the book The Ray Tracer Challenge with F#. The book is language agnostic and represents the code with pseudocode and presents a test driven approach. My repository is here: https://github.com/bmitc/the-ray-tracer-challenge-fsharp

I highly recommend the two books:

Ray Tracing in One Weekend: https://www.amazon.com/dp/B01B5AODD8/

The Ray Tracer Challenge: https://www.amazon.com/dp/1680502719/

For the latter, I have made it a pretty good way through the book, implementing a functional (in the programming paradigm sense) version of the ray tracer in F#. It’s actually rather mind boggling how close the F# code and tests are to the psuedocode found in the book.

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