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From: Stefan Holdermans <stefan@vectorfabrics.com>
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Subject: Re: [Caml-list] What is an applicative functor?

Dawid,

> What does it mean that a functor is applicative?
> Is there any analogy between applicative functors in OCaml and the Applicative type class of Haskell?

There is no analogy; functors in Caml are quite different from functors in Haskell. In Caml, a Functor is a higher-order module, i.e., a module that takes other modules as input in order to produce a proper module. In Haskell, Functor is a type class: essentially, the collection of types of kind * -> * that come with a structure preserving, covariant map operation. Applicative functors are members of this collection that fulfill some extra requirements.

Cheers,

  Stefan