Functional Programming in C++
I was afraid this would be some sort of contorted framework to let you use C++ to write Lisp. Glad I was wrong. Carmack is spot-on here:"My pragmatic summary:  A large fraction of the flaws in software development are due to programmers not fully understanding all the possible states their code may execute in.  In a multithreaded environment, the lack of understanding and the resulting problems are greatly amplified, almost to the point of panic if you are paying attention.  Programming in a functional style makes the state presented to your code explicit, which makes it much easier to reason about, and, in a completely pure system, makes thread race conditions impossible."Too often I've seen functional proponents, when asked why we ought to use functional languages, rely on facile arguments such as "it makes your code more concise, therefore easier to hold in your head" or "it makes your code more mathematical, and therefore easier to reason about". Like Rich Hickey, Carmack gets it right.