Packages

Builds on the Mox pattern — generates behaviours and dispatch facades from `defcallback` declarations — and adds stateful test doubles powerful enough to test Ecto.Repo operations without a database.

Core effect system for Elixir: write business logic as pure effect descriptions, swap handlers for testing. Provides the Comp engine and foundational effects (State, Reader, Writer, Throw, Yield).

HexPort: Hexagonal architecture ports for Elixir. Typed port contracts with async-safe test doubles, dispatch logging, and stateful test handlers. Define boundaries with `defport`, swap implementations for testing without a database.

Cooperative concurrency for Skuld: FiberPool scheduler, Channel, Brook streaming, Yield, and AsyncCoroutine process bridging.

Algebraic effects and handlers for Elixir.

Port effect and adapter bridge for Skuld: dispatch blocking calls to pluggable backends and bridge effectful implementations to plain Elixir interfaces.

Query batching system for Skuld: typed batchable fetch contracts with automatic concurrent batching.

Ecto Repo integration for Skuld: effectful dispatch facade for standard Ecto Repo operations.

Multi-process execution for Skuld: Parallel and AtomicState effects.

Durable execution for Skuld: SerializableCoroutine and EffectLogger for capturing and replaying effect logs.