Reification and type-safety in a CQRS world
summary
Built a small Scala CQRS library called fun-secure that compares three concrete ways to glue domain ADTs, Commands and Events: type-parameter plumbing, type-member/type-projection companions, and a working path-dependent implicit trick that registers companion types into implicit scope. Backends include Akka and an in-memory interpreter so tests return pure events not Futures. The system validates event handlers before persisting to avoid invalid state, and supports commands emitting multiple events.
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chapters (18)
- 0:00Introduction
- 1:25The problem
- 2:46Secure as framework
- 6:00Reification
- 9:00Behavior
- 14:05Commands Behavior
- 15:40DSL
- 17:23Type Parameters
- 20:37Type projections
- 22:03Type rejection
- 25:33Type actions
- 26:43Type objects
- 30:25Pathdependent types
- 31:30Implicit scope
- 34:23Akka
- 36:10InMemory Backend
- 39:44Wrapup
- 43:39Command and events
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