Effekt: Extensible Algebraic Effects in Scala (Short Paper)

by Jonathan Immanuel Brachthäuser and Philipp Schuster

In Proceedings of the International Symposium on Scala. ACM Press, 2017.

This publication is related to the Lexical Effect Handlers research project.


Algebraic effects are an interesting way to structure effectful programs and offer new modularity properties. We present the Scala library Effekt, which is implemented in terms of a monad for multi-prompt delimited continuations and centered around capability passing. This makes the newly proposed feature of implicit function types a perfect fit for the syntax of our library. Basing the library design on capability passing and a polymorphic embedding of effect handlers furthermore opens up interesting dimensions of extensibility. Preliminary benchmarks comparing Effekt with an established library suggest significant speedups.


Video recording of the talk available on YouTube.