Parallel Algebraic Effect Handlers

TL;DR

This paper introduces a formal calculus for parallel algebraic effect handlers, enabling concurrent effect management and providing a Haskell implementation to support future development in this area.

Contribution

It formalizes {1}p, modeling effect handlers with parallelizable computations, and demonstrates expressibility and implementation insights for parallel algebraic effects.

Findings

Formalization of {1}p calculus for parallel effects

Examples demonstrating expressibility in the calculus

Haskell implementation supporting future research

Abstract

Algebraic effects and handlers support composable and structured control-flow abstraction. However, existing designs of algebraic effects often require effects to be executed sequentially. This paper studies parallel algebraic effect handlers. In particular, we formalize {\lambda}p, an untyped lambda calculus which models two key features, effect handlers and parallelizable computations, the latter of which takes the form of a for expression as inspired by the Dex programming language. We present various interesting examples expressible in our calculus, and provide a Haskell implementation. We hope this paper provides a basis for future designs and implementations of parallel algebraic effect handlers.