data-effects-th

Template Haskell utilities for the data-effects library.

LTS Haskell 24.28:	0.4.2.1
Stackage Nightly 2026-01-18:	0.4.2.1
Latest on Hackage:	0.4.2.1

See all snapshots data-effects-th appears in

MPL-2.0 licensed by Sayo contributors

Maintained by ymdfield

This version can be pinned in stack with:data-effects-th-0.4.2.1@sha256:48137fecbf8c2312c5996e76595c0efe66f3d19f09dbe35a4595323177b1c344,3399

Module documentation for 0.4.2.1

Data
- Data.Effect
  - Data.Effect.HFunctor
    - Data.Effect.HFunctor.TH
      - Data.Effect.HFunctor.TH.Internal
  - Data.Effect.TH
    - Data.Effect.TH.Internal

Depends on 12 packages(full list with versions):

data-default, data-effects-core, either, extra, infinite-list, lens, th-abstraction

Used by 1 package in nightly-2026-01-18(full list with versions):

data-effects

A basic framework for a Haskell effect system library based on GADTs-based effect representations with a style that separates first-order effects and higher-order effects.

This library set was created by being separated from the Heftia extensible effects library.

Your contributions are welcome!

Please see CONTRIBUTING.md.

Acknowledgements, citations, and related work

The following is a non-exhaustive list of people and works that have had a significant impact, directly or indirectly, on its design and implementation:

Casper Bach Poulsen and Cas van der Rest — Hefty Algebras: Modular Elaboration of Higher-Order Algebraic Effects
Patrick Bahr and Tom Hvitved — compdata: Compositional Data Types
Michael Szvetits — effet

Changes

Revision history for data-effects-th

0.1.0.0 – 2023-09-18

Initial public release.

0.1.1.0 – 2024-09-01

Fix an issue where constraints in the effect constructor were not properly reflected in ‘genLiftFOEPatternSynonyms’.
Fixed an issue where the auto-generation would fail when the name of the effect constructor started with a colon (:) operator.

0.2.0.0 – 2024-10-10

Support for the core version upgrade to 0.2.
- Support for GHC 9.8.2.

0.4.0.0 – 2025-04-16

Adopt to the new v4 interface.
- Unified first-order and higher-order effect interfaces.
- Added a generic Eff carrier type.