language-ext

Option<V> for example - this makes composition more difficult). So although the language has been steadily going in the right direction, there has been less of a concerted effort on the library front. And therefore C# is still behind IMHO. This is something I've been trying to rectify, by essentially building a functional BCL [1]. I welcome the increased pace of functional features recently. Although sometimes it's frustrating seeing the direction they're going and wishing they'd get there much quicker (expressions everywhere, sum-types, record-types, better type inference). It's interesting that often C# is held up for its inability to do type-classes or ad-hoc polymorphism. But it is in fact possible with C# today [2] [3], and with zero cost (i.e. no reflection, additional memory allocations, or side-stepping of the type-system). It just causes a massive head-ache of manually provided generic arguments... [4] [5] I'd love it if the Roslyn team took some time to deal with the generic parameters inference story. It would help bring ad-hoc polymorphic types to C#, but it would just be awesome in general. [1] https://github.com/louthy/language-ext [2] https://github.com/louthy/language-ext/blob/type-classes/Lan... [3] https://github.com/louthy/language-ext/blob/type-classes/Lan... [4] https://github.com/louthy/language-ext/blob/type-classes/Lan... [5] https://github.com/louthy/language-ext/blob/type-classes/Lan...

f Some(x) and None, I instead use a struct (to remove a 3rd state of null). With the 'is' operator I'm hoping to do this: public static class Some { public static bool operator is(Option<T> option, out T value) { value = option.Value; // Value is internal return option.IsSome; } } switch(option) { case Some x: ...; break; default: ...; break; } I'm not sure if I can do this: public static class None { public static bool operator is(Option<T> option) { return option.IsNone; } } switch(option) { case Some x: ...; break; case None: ...; break; } So although it doesn't solve the general need for sum-types and record-types, it should hopefully facilitate some of the common use cases. Agreed about ref and out; I understand their purpose, I just despise them with a passion. Their whole syntax and ickyness makes me feel queesy. The inline var out feels like an imbalanced expression. They're clearly more useful now, but they still feel odd. [1] https://github.com/louthy/language-ext/blob/master/LanguageE...

ved them from the language. Ugly, error magnets. All in all, good progress. Hopefully they can make more progress on facilitating expression-based programming, and bring in record types for the next release. The pain of creating immutable types is truly tedious. And I'd desperately like to see partial generic parameter specifying (for when one of the generic arguments can't be inferred by the type-system, so you then end up having to specify them all). [1] https://github.com/louthy/language-ext/blob/master/LanguageE... [2] https://github.com/louthy/language-ext/blob/master/LanguageE... [3] https://github.com/louthy/language-ext/blob/type-classes/Lan...

ike. But you miss out on some of the amazing type system benefits of F# if you do that. What I tend to do is design all of the types first, as records or discriminated unions. A bit like if you were doing a DB related project you might spend some time designing the schema first, thinking about how the data should be laid out. With ADTs you can design the states of your application, whatever it is, and then you write the functions that transform those states in a referentially transparent way. Then you book-end your lovely functional code with the IO. This whole process is much simpler when you start with smaller services; so if you've found sections of your existing app that you want to break out, then that's perfect. By the way, if you want some of the functional niceness in C# too, then check my library below. It was built with your situation in mind (because it's mine too). It also has some utility functions for F#/C# interop. [1] https://github.com/louthy/language-ext