Declarative axiomatic and provable correct systems in Swift

Swift's type system allows the creation of small self-contained modules controllable by sending typed messages. These messages DSL type encodes commands that can follow spoken english quite closely, i.e.: .increase(.brightness,by:10.point,on:light)) increases the brightness of light by 10% points. In this tutorial we will implement an application using «Khipu», a fully immutable implementation of Robert C. Martin's «Clean Architecture». Khipu is fully testable with tests not only valid in TDD, but en par with the Scientific Method itself. We will explore «Partial Application» as an alternative to problematic class-centred designs.