Ep 8: Compose Yourself with Scala 3's Opaque Types

Justin Heyes-Jones demonstrates how to build Monoid and Semigroup type classes in Scala 3 using opaque types.

In this video I build type classes for Monoids and Semigroups using Scala 3, then show how we can make simple instances like adding integers, how to make an instance for a "newtype" that multiplies integers (using Scala 3's new opaque types for that), and finally a more complex instance that composes two maps together. See also: There is no blog post with this video but I wrote a blog about Monoids a couple of years ago, describing how they were used to handle all the purchasing of items in a mobile video game... justinhj.github.io/2019/06/10/monoids-for-production.html See "the red book" but also Runar's post below: manning.com/books/functional-programming-in-scala apocalisp.wordpress.com/2010/06/14/on-monoids/ Scala stuff by me Video editing by Jamie Intro music "Functional Justin Intro 1" by me ©2020-20021 Justin Heyes-Jones All Rights Reserved