expression-problem

Table of Contents Keywords Expression Problem Introduction Following the ritual Not following the ritual Preface 2 classical ways to implement analytics library Enum based (Sum type based) Class, struct+protocol based (product type based) Client problem: Add ForceTapEvent & support another analytics service The limitation of enum approach The limitation of class/(struct+protocol) based approach Summarizing A radical way to solve the same issue aka Tagless final Lets get both: ability to add cases and new interpretation.