@hackage heftia0.2.0.0

higher-order effects done right

Heftia is a higher-order effects version of Freer.

This library provides "continuation-based semantics" for higher-order effects, the same as lexi-lambda's eff. Instead of using the IO monad to implement delimited continuations for effects, Heftia internally uses Freer monad.

The paper

  • Casper Bach Poulsen and Cas van der Rest. 2023. Hefty Algebras: Modular Elaboration of Higher-Order Algebraic Effects. Proc. ACM Program. Lang. 7, POPL, Article 62 (January 2023), 31 pages. https://doi.org/10.1145/3571255

inspires this library. Hefty trees, proposed by the above paper, are extensions of free monads, allowing for a straightforward treatment of higher-order effects.

This library provides Hefty monads and Freer monads, encoded into data types in several ways to enable tuning in pursuit of high performance.