# ten: Functors et al. over arity-1 type constructors

[ apache, data, library ] [ Propose Tags ]

This provides a mirror of the traditional typeclass hierarchy for types of kind (k -> Type) -> Type, or functors from the category Hask{k} to Hask, where Hask{k} denotes the category whose objects are mappings from k to Type, and whose morphisms are the parametric functions between them. In general, these functors look like variations on the theme of "polymorphic records", also frequently described as "higher-kinded data".

We currently provide the following classes, which correspond directly to their equivalents in "base" or "adjunctions": Functor10, Foldable10, Traversable10, Applicative10, and Representable10. Additionally, a class Constrained10 provides instances for the argument of each occurrence of the type parameter in a value.