For those you want to learn the functional programming I'd suggest to immedeately commence looking at Ocaml/Haskell instead to see the real big picture. Because it's of course adorable that you can write map and compose in JS (it's 2014, it can do it everywhere), but FP = many more serious things.
I've been wondering lately, if we skip performance as a consideration (for example lazy evaluation), what is the difference between functional programming and imperative programming without globals, pointers, mutable variables or shared memory? In other words, would an imperative language without side effects (that could do static code analysis) be any different in practice than FP? I'm very serious about this, becau…
This actually sounds pretty nice to write as a shell pipeline (and that's a really good way to do it), but really, it's likely that you'd end up writing some code like
main() {
q = queue(5);
avg = 0;
while(!eof) {
r, eof = get_record();
t = transform(r);
if(q.size() >= 5){
avg -= q.pop();
}
avg += t;
q.push(t);
print avg/q.size();
}
}
I claim that it's possible to factor that code nicely out in Haskell, and still get the compiler to generate the same machine code as the C loop. This doesn't particularly use first class functions, and more relies on the combo of sufficiently smart compiler and sufficiently strong guarantees about what code will do.
I also take slight offense at calling C-style languages "plain old algebraic style", since it'd be really strange in algebra to say both x=5 and x=6. I would not hesitate to call FP languages where you can substitute equals for equals and such the algebraic languages.