Imperative languages, most recently JavaScript. One thing that comes to mind is how elegantly this book uses Haskell data types to define pitch classes and tot

Imperative languages, most recently JavaScript. One thing that comes to mind is how elegantly this book uses Haskell data types to define pitch classes and total functions for them. The abstraction techniques made me confident in the abstractions in a way I’ve never been for any imperative or dynamically typed language. By comparison, other software started to look brittle and issue-prone.