anchor.diff:  
   The Functor class is the most basic and ubiquitous type class in the _cats_ libraries. A simple intuition is that
   a Functor represents a "container" of some sort, along with the ability to apply a function uniformly to every
  -xelement in the container. For example, a list is a container of elements, and we can apply a function to every
  +element in the container. For example, a list is a container of elements, and we can apply a function to every
   element of a list, using map. As another example, a binary tree is also a container of elements, and it’s not
   hard to come up with a way to recursively apply a function to every element in a tree.
   
  
positive.code: [NOTE]
  ====
  The real fmap signature is `(a -> b) -> f a -> f b` that can be traslated to clojure `[f fv]`. The changed
  order on protocol definition is required because of clojure's protocols limitation on dispatch on first 
  argument. You should not use protocol function directly, for it, `cats.core/fmap` exists and has the correct
  signature.
  ====
  
negative.code: Category Theory abstractions for Clojure
  ========================================
  Andrey Antukh & Alejandro Gómez
  0.1.0, 2014-06-06
  
  :toc:
  
  