anchor.diff:  
   Unlike Clojure and other Clojure contrib libs, does not have many restrictions for
   contributions. Just open a issue or pull request.
  +
   
   === Get the Code
   
  
positive.code: ;; => Stdout: 83
  ----
  
  We can observe that it returns the same result as in previous example,
  but takes almost the half of time to finish execute all the computations. This
  is happens because `alet` is more smarter macro and calculates de dependencies
  between declared bindings and executes them in batches.
  
  
negative.code: 
  In this example we have used the `mlet` macro from the `cats` library.
  
  Behind the scenes, the _promise_ library implements and uses monadic abstractions.
  And in this case, the _Promise_ type implements a _Functor_ and _Monad_ abstractions.
  
  This part of the documentation, requires a minimal amount of knowledge about these
  concepts. However, it is not mandatory to read and understand this portion in order
  to make use of this library.
  
  Previously we have seen the `mlet` macro which is very similar in functionality to
  the ES7 `async` and `await` functions.
  
  The main difference with the ES7 syntax is that it is not bound only to promises.
  It is a generic and extensible abstraction that allows you to work with different
  types of logic allowing for composition of computations.
  
  Please, read the link:http://funcool.github.io/cats/latest/[cats documentation]
  to see other types and abstractions.
  
  
  === Raw access to bluebird api
  