| Rational | Control.Category.Hask, Control.Category.Constrained.Prelude |
| Read | Control.Category.Hask, Control.Category.Constrained.Prelude |
| read | Control.Category.Hask, Control.Category.Constrained.Prelude |
| readFile | Control.Category.Hask, Control.Category.Constrained.Prelude |
| readIO | Control.Category.Hask, Control.Category.Constrained.Prelude |
| readList | Control.Category.Hask, Control.Category.Constrained.Prelude |
| readLn | Control.Category.Hask, Control.Category.Constrained.Prelude |
| readParen | Control.Category.Hask, Control.Category.Constrained.Prelude |
| ReadS | Control.Category.Hask, Control.Category.Constrained.Prelude |
| reads | Control.Category.Hask, Control.Category.Constrained.Prelude |
| readsPrec | Control.Category.Hask, Control.Category.Constrained.Prelude |
| Real | Control.Category.Hask, Control.Category.Constrained.Prelude |
| RealFloat | Control.Category.Hask, Control.Category.Constrained.Prelude |
| RealFrac | Control.Category.Hask, Control.Category.Constrained.Prelude |
| realToFrac | Control.Category.Hask, Control.Category.Constrained.Prelude |
| ReCartesian | |
| 1 (Type/Class) | Control.Category.Constrained.Reified |
| 2 (Data Constructor) | Control.Category.Constrained.Reified |
| ReCategory | |
| 1 (Type/Class) | Control.Category.Constrained.Reified |
| 2 (Data Constructor) | Control.Category.Constrained.Reified |
| recip | Control.Category.Hask, Control.Category.Constrained.Prelude |
| Refl | Control.Category.Discrete |
| Regroup | Control.Category.Constrained.Reified.PolyPattern |
| regroup | Control.Category.Constrained, Control.Category.Constrained.Prelude |
| Regroup' | Control.Category.Constrained.Reified.PolyPattern |
| regroup' | Control.Category.Constrained, Control.Category.Constrained.Prelude |
| rem | Control.Category.Hask, Control.Category.Constrained.Prelude |
| ReMorphism | |
| 1 (Type/Class) | Control.Category.Constrained.Reified |
| 2 (Data Constructor) | Control.Category.Constrained.Reified |
| repeat | Control.Category.Hask, Control.Category.Constrained.Prelude |
| replicate | Control.Category.Hask, Control.Category.Constrained.Prelude |
| replicateM | Control.Category.Hask |
| replicateM_ | Control.Category.Hask |
| RePreArrow | |
| 1 (Type/Class) | Control.Category.Constrained.Reified |
| 2 (Data Constructor) | Control.Category.Constrained.Reified |
| return | |
| 1 (Function) | Control.Category.Hask |
| 2 (Function) | Control.Monad.Constrained, Control.Category.Constrained.Prelude |
| reverse | Control.Category.Hask, Control.Category.Constrained.Prelude |
| ReWellPointed | |
| 1 (Type/Class) | Control.Category.Constrained.Reified |
| 2 (Data Constructor) | Control.Category.Constrained.Reified |
| RFactor | Data.CategoryObject.Product |
| rfactorProj | Data.CategoryObject.Product |
| Right | Control.Category.Hask, Control.Category.Constrained.Prelude |
| right | Control.Arrow.Constrained |
| round | Control.Category.Hask, Control.Category.Constrained.Prelude |
| runGenericAgent | Control.Category.Constrained, Control.Category.Constrained.Prelude |
| runKleisli | Control.Monad.Constrained, Control.Category.Constrained.Prelude |