What are the advantages of functional programming for practical work in software engineering? Why are functional programming features being added to many programming languages today, and what exactly are these features?

The exact meaning of "functional programming" has been debated. I adopt an extreme pragmatic and un-academic approach and ask the question from a software engineer's point of view: what specific advantages does FP provide? I focus not on the theoretical advantages that help computer scientists to publish more papers, but on practical features that drive the industry adoption of FP by helping programmers write better code. I describe four main FP idioms that pervade the industrial FP usage today: loop-free iteration, type parameters, disjunctive types, and effect chaining. Programmers who master these features and idioms will become more productive in any language.

There are four main features (or idioms) that define what "functional programming" means in today's practice of software engineering:…

Rant time! There's this concept that keeps coming up in software engineering: represent your program as a directed graph, where nodes are computations and edges are data. Technical term is "dataflow programming", but the same idea appears everywhere.