Some functional types in C#

Posted on 2015-08-03 Updated on 2016-08-03

Update: I now have a project on GitHub containing this code at https://github.com/Richiban/Richiban.Func Check this repository for up to date code.

Continuing with my long-running train of thought in bringing some functional programming concepts to my C# projects, I have implemented a type called Optional, roughly equivalent to `Option` from F# or `Maybe a` from Haskell. If you’re not familiar with these concepts, then imagine Nullable from .NET, but applicable to all types (not just value types). The whole idea is that, rather than using a null reference of T to represent a missing value you use a new type–Optional–that can exist in one of two states: it either contains a value of T or does not.

This is a very important difference that I will explain over the course of this post. First, let’s look at the type definition itself. It’s quite long, so feel free to skim-read it at this point and refer back to it at later points in the post.

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