Architecture

Skuld uses evidence-passing style where:

1. Handlers are stored in the environment as functions
2. Effects look up their handler and call it directly
3. CPS enables control effects (Yield, Throw) to manipulate continuations
4. Scoped handlers automatically manage handler installation/cleanup

Comparison with Freyja

Skuld was built after Freyja proved to have significant limitations, including performance issues and requiring two monad types (Freer and Hefty), with all the additional complexity and mental load that imposes. Skuld's client API looks quite similar to Freyja, but the implementation is very different - Skuld performs better and has a simpler, more coherent API.

Skuld's performance advantage comes from avoiding Freer monad object allocation, continuation queue management, and linear search for handlers.