https://kant2002.github.io/fsharpforfunandprofit.com/csharp/Recent content in F# for C# Programmers on F# for Fun and ProfitHugo -- gohugo.iouk-uaWed, 01 Jan 2020 00:00:00 +0000https://kant2002.github.io/fsharpforfunandprofit.com/csharp/union-types-in-csharp/Mon, 01 Jan 0001 00:00:00 +0000https://kant2002.github.io/fsharpforfunandprofit.com/csharp/union-types-in-csharp/This is an appendix to the post on “designing for correctness”. In that post, I had some requirements for a simple shopping cart. I showed some bad C# code, and some F# code that implemented the requirements easily. There are some responses that come up when a C# developer looks at the F# code, such as “why not just use an interface?” or “what about the visitor pattern?” In this post, I’ll demonstrate why the solution is not as straightforward as you might think.