Category Theory, The Essence of Interface-Based Design - Erik Meijer
Category Theory is the mathematicians' interpretation of interface-based design, so whenever you hack together a new API in your favourite OO language, it is always a smart idea to ask the question x -LT "What would x do?" applied to the Category Theorist that worked on your same problem already decades ago. Since lambda expressions are the new hot topic all across programming language land these days, we will invoke our question of conscience with "Joachim Lambek" and learn that Java 8 lambdas and method references are simply a Cartesian Closed Category, proving yet again that interfaces are the OO developers' interpretation of Category Theory. http://fal.cn/EhAk