The combined power of F# and C#

[giscus[bot]]

The combined power of F# and C#

Where C# is the most dominant language in the .NET world, other languages are built on top of the Framework that deserves their respective place. F# is strong when it comes down to functional programming! In this blog post, we will leverage the power of F# and C# to showcase where both excel!

https://steven-giesel.com/blogPost/2f70d926-ec92-4dfe-b278-18f78078253d

[aweadd014w]

hi Steven! Thank you for sharing! I can't find the source codes in the repository. Could you please have a look?

[linkdotnet]

Yes - because I forgot to push the changes :)
That is on me, sorry. Will do this evening.

[saint4eva]

Kindly use the required keyword and remove the constructor. And if you like, you can use records also

[keithn]

here's an example I did ages ago based on F# for fun and profits "sell" for DUs.... https://fsharpforfunandprofit.com/posts/designing-for-correctness/ , and in C# https://gist.github.com/keithn/ceeeed5f7eb567e1b2333747065d10dd If you are having trouble, just ignore the inheritance and you'll see it's just the same.

[linkdotnet]

Fair point - I took your code @keithn and if you convert from F# to C# the compiler indeed uses inheritance.

Does it fall short if you defined DU's recursively, like this?

type Tree =
    | Branch of int * Tree list
    | Leaf of int

[stroborobo]

Frankly, inheritance is an implementation detail, exhaustiveness however is a core property of sum types.

[keithn]

@stroborobo you can actually promote the C# warning to an error if you want to get exhaustiveness checks, but it's not really a core property and I never miss it.

[stroborobo]

Could you do private abstract base and public sealed cases?

Don't get me wrong, I'd do a little happy dance when C# gets first class DU support, but the exhaustiveness just is part of its definition. And when you work with this property regularly and use it to prevent impossible states, it becomes a very helpful tool.

[keithn]

yeah, you can do recursion, so you can do something like...

public abstract record Tree
{
    public record Branch(int Value, ImmutableList<Tree> Children) : Tree;
    public record Leaf(int Value) : Tree;
}