issue #335 documentation improvements

monad/index.md

@@ -3,17 +3,21 @@ layout: pattern
 title: Monad
 folder: monad
 permalink: /patterns/monad/
-categories: Presentation Tier
+categories: Other
 tags:
  - Java
  - Difficulty-Advanced
+ - Functional
 ---
 
 ## Intent
 
 Monad pattern based on monad from linear algebra represents the way of chaining operations
 together step by step. Binding functions can be described as passing one's output to another's input
-basing on the 'same type' contract.
+basing on the 'same type' contract. Formally, monad consists of a type constructor M and two
+operations:
+bind - that takes monadic object and a function from plain object to monadic value and returns monadic value
+return - that takse plain type object and returns this object wrapped in a monadic value.
 
 ![alt text](./etc/monad.png "Monad")
 
@@ -25,5 +29,7 @@ Use the Monad in any of the following situations
 * when you want to apply each function regardless of the result of any of them
 
 ## Credits
+
 * [Design Pattern Reloaded by Remi Forax](https://youtu.be/-k2X7guaArU)
 * [Brian Beckman: Don't fear the Monad](https://channel9.msdn.com/Shows/Going+Deep/Brian-Beckman-Dont-fear-the-Monads)
+* [Monad (functional programming) on Wikipedia] (https://en.wikipedia.org/wiki/Monad_(functional_programming)