Lambda the Ultimate

Programming with Algebraic Effects and Handlers. Andrej Bauer and Matija Pretnar, arXiv preprint.

Eff is a programming language based on the algebraic approach to computational effects, in which effects are viewed as algebraic operations and effect handlers as homomorphisms from free algebras. Eff supports first-class effects and handlers through which we may easily define new computational effects, seamlessly combine existing ones, and handle them in novel ways. We give a denotational semantics of eff and discuss a prototype implementation based on it. Through examples we demonstrate how the standard effects are treated in eff, and how eff supports programming techniques that use various forms of delimited continuations, such as backtracking, breadth-first search, selection functionals, cooperative multi-threading, and others.

Eff has been discussed here before, and it's nice to see some more progress and a much more complete introduction. The paper is intended for a general audience (well, a general audience of PL enthusiasts). It's quite clear and contains a wealth of examples.