> I would like to add that recursive calls can be nicer than loops

Having a good library of higher-order functions that encapsulate common recursion patterns is a lot nicer than doing recursion by hand, or having to read code where someone did recursion by hand and you have to not only figure out how the recursion works, but whether the author did anything wrong.

Higher-order functions are control structures, and we should encourage their use for all the same reasons we encourage the use of while loops in preference to people building their loop structures by hand out of gotos and conditional gotos.

I think recursive solutions are often very nice indeed. But at worst, recursive solutions are sometimes worse than structured loops, because you can use recursions very much like a free-style goto, allowing your code to have even less restrictive structure than loops. That's why directly recursive code is usually discouraged and reusing recursive combinators is encouraged.

I agree that purity is often used as a buzzword.

To parody this, Conal Elliott wrote the "C is purely functional" blog post: http://conal.net/blog/posts/the-c-language-is-purely-functio...

To resolve this, a nice suggestion is to use the term "denotative programming". That is, programming where types and values have mathematically simple denotations that predictably compose exactly according to the syntactic composition being used.

Tail-recursive calls are essentially gotos, but a little more well behaved (if you try to put state into explicit parameters instead of mutable variables).