This library provides definitions for CEPs (classy-effects protocols) to standardize and unify the definition of effects in Haskell in a backend-library-agnostic manner. It also includes several standard effect definitions defined in compliance with CEPs, and Template Haskell functions to automatically make type classes conform to CEPs as effect classes. Please refer to CEPs for details. The Template Haskell functions are re-exported from the classy-effects-th package, while the fundamental definitions are re-exported from the classy-effects-base package. This 'classy-effects' project was abandoned due to the discovery of fundamental difficulties. The reasons are as follows: https://github.com/orgs/sayo-hs/projects/4?pane=issue&itemId=48547880 As an alternative, consider using 'sayo-hs/data-effects', a GADTs-based common effect representation foundation: https://github.com/sayo-hs/data-effects.