It is disingenous in the extreme to ask, "So what’s all this talk about mutation and state? Well, who said you can’t have state in functional programming?" when

It is disingenous in the extreme to ask, "So what’s all this talk about mutation and state? Well, who said you can’t have state in functional programming?" when the very first line of the very first hit on "functional programming mutation state" is the Wikipedia article on functional programming, which says: "In computer science, functional programming is a programming paradigm—a style of building the structure and elements of computer programs—that treats computation as the evaluation of mathematical functions and avoids changing-state and mutable data." -- https://en.wikipedia.org/wiki/Functional_programming https://en.wikipedia.org/wiki/Functional_programming So the answer to the question "Who said you can't have state in functional programming?" is: "Every introduction to functional programming ever." This is why people hate Haskell and make fun of Haskellers. In their quest to appear more clever than the rest of us, they engage in utterly disingenous rhetoric. Which is too bad, because I'm pretty sure they are actually more clever than the rest of us--certainly more clever than me--and don't need this nonsense. Haskell is an amazingly cool language, and I've talked to people at meetups who are using it for interesting things, and learning a bit of it myself has been an interesting and educational challenge. But getting around to learning it took five years longer than it should have because I was so put off by the rhetorical nonsense the language community engages in.