anchor.diff:  methods! In fact, func􀦞ons themselves have useful methods for composi􀦞on:
   
   == Closures
  -Close over variables and functions. Everything used within the curly braces is essentially 
  +Close over variables and functions. Everything used within the curly braces is essentially
   kept alive whilst the closed over function is passed around and used by the application.
   
   === Futures and Promises
   
  -Future[T] 
  +Future[T]
   
   Callbacks always return the values
   . onComplete.
  
positive.code: == Functional programming
  
  Functional programming is not only about composing functions and algebraic data structures — it makes concurrency composable 
  
  Functional programming or (Declarative programming) in the long term is a vision for computer 
  programming: the programmer should say only what he or she wants, and the computer 
  should figure out how to calculate it.
  
  Everything you wanted to know about http://bartoszmilewski.com/2014/10/28/category-theory-for-programmers-the-preface/[Category theory]
  
  ===== Origins (why FP now?)
  
  It seemed like denotational semantics wasn’t the best fit for a considerable number of important tasks 
  that were essential for writing useful programs, and which could be easily tackled by operational semantics. 
  The breakthrough came from category theory. Eugenio Moggi discovered that computational effect can be mapped to monads. 
  This turned out to be an important observation that not only gave denotational semantics a new lease on life and 
  made pure functional programs more usable, but also shed new light on traditional programming. 
  footnote:[http://bartoszmilewski.com/2014/11/24/types-and-functions]
  
  === Category and composition
  
negative.code: Everything you wanted to know about http://bartoszmilewski.com/2014/10/28/category-theory-for-programmers-the-preface/[Category theory]
  
  === Procedural concept
  Procedures have two important properties: they are values and they have a contextual environment.
  The combination of these two properties leads to very powerful programming techniques.
  In fact, we can say that the whole layered construction of data abstractions that gives today's
  programming systems so much power is based on procedures with these two properties!
  So the procedure concept, as defined here, is one of the most important concepts in all of computer programming.
  