Comment by BeetleB

Yes, but how do you chain them?

    map(func4, map(func3, map(func2, map(func1, iter))))

vs

    iter.map(f1).map(f2).map(f3).map(f4)

I made up the syntax for the last one, but most functional languages have a nice syntax for it. Here's F#:

    iter |> f1 |> f2 |> f3 |> f4

Or plain shell:

    command | f1 | f2 | f3 | f4