GitHub - dorchard/effect-monad: Provides 'graded monads' and 'parameterised monads' to Haskell, enabling fine-grained reasoning about effects.

Graded monads are a generalisation of monads where, from a functional programming perspective, a monadic type constructor is annotated (indexed) by another type representing effect information that explains the effects of a computation, i.e., values of type M r a are effectul computations of values of type a with effects r. They provide a way to give finer-grained information about impurity and ca

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“values of type `M r a` are effectul computations of values of type `a` with effects `r`. They provide a way to give finer-grained information about impurity”