Tagged data in Haskell (SICP 2.4.2) (opens in new tab)

I have a copy of SICP, or as it is also known, The Wizard Book. This book is widely praised, but I can’t take the time to work my way through all of it. However, sometimes I jump into parts of it that look interesting. Today, we’ll see how to support multiple representations of data through tagging. This article is written in Haskell throughout, but at the start it will look a lot like the Lisp code in SICP. I have intentionally tried to recreate the SICP solution as closely as possible, incl...