Functional Patterns in Domain Modeling — Debasish Ghosh

Domain modeling has traditionally been viewed and implemented using OO techniques and class based OO languages. The focus being the domain itself, existing literature has espoused us to start looking into the nouns of the domain. Classes first, accompanied with deep nested inheritance hierarchies form the backbone of many domain model implementations today.

In this talk we will take a radically different approach. We will start with a focus on the verbs first, think about domain behaviors and how we can model them using pure functions grouped together within extensible containers called modules. We will take an algebraic approach towards evolution of these modules, the algebra being composed of functions, types and laws. We will see how the domain algebra can be constructed as a composition of algebras from standard categorical structures like monoids, functors and monads.

We will conclude the talk with an introduction to property based verification of domain laws which are essentially the properties of the domain algebra. The discussion will be based on Scala and we will make heavy usage of the static type system that the language offers.